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广西医科大学. Computer Networking. 网络课件. 双语教学. 模拟实验. 计算机网络教研室. DI. 1. 2. 3. CHAPTER 3 Network Architetures and Standarts. The first section. Exercises. Online lecture. 3-7. 3-4. 3-1. 3-13. 3-10. A caveat about. Standards making org. Advs and disadvs of standards. - PowerPoint PPT Presentation
Citation preview
Computer Networking
网络课件 双语教学 模拟实验
广西医科大学
计算机网络教研室
Department of Computer Networking Application
CHAPTER 3 Network Architetures and Standarts
DI1 The first section
2 Exercises
3 Online lecture
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Introduction3-1
Definition Architecture3-2
Why have Architecture3-3 3-10
Definition Architecture3-5
The Vand Xstandards3-6
Advs and disadvs of standards3-7
Communication Architecture3-8
ISO Reference Model3-9
Standards making org3-4 Internet Architecture3-11
Manufactures Architecture3-12
A caveat about3-13
Layered architecture3-14
TCPIP Architecture
Network Management and Operation wwwgxmueducn
OBJECTIVESExplain the difference between architectures and standardsExplain the need for network architecture and standardsIdentify a number of communications standards-making orgDescribe the OSI model architectureDescribe TCPIP architectureDescribe the architecture of the InternetDiscuss the ADV and DISADV of layered architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
31 IntroductionDefinitions of architectures and standardsThe difference among themThe need of themSpecific example of themExamine adv amp disadv
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
32 DEFINITION OF ARCHITECTURES AND STANDARDS
Architecture is a plan or direction that is oriented toward the needs of the userNetwork architecture is a set of principles used as the basic for the design and implementation of a communications network
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
It includes the organization of functions that must be performed by the network and the description of data formats and procedures
Network architecture=layer + protocols
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network architecture features
May or may not conform to standards Donrsquot provides enough detail how network to be implemented Provides a set of generic concepts Most architecture (plan) are designed for the long term use
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Single Layer Model First Communication Between Computer DevicesThe communication and application software be intermingled (To mix)
DEVICE A
Hardwareamp
Software
Hardwareamp
Software
DEVICE B1
The early networks were not flexibleSingle specification for all aspects of communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA(System Network Architecture)
IBM 1974 by the first computer network architectureIBMrsquos SNA is a proprietary architectureNOTENot SNA(storage area network) Most network architectures developed since use a layered approach
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Communication standardThe rules that are established to ensure compatibility among similar communications products and servicesCommunications standards are the flesh on the architectural skeletonThey specify how a particular communications product serviceor interface will operate
V90 modem
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
33 why have network architectures
1Communication system were becoming too complex2 wanted to be isolated from the complexities of the network3Wanted to connect different types of devices to the network4Distributed processing and client-server processing became practical5Network needed to be managed
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
BackgroundCommunications vendors realized early standardscomputer manufacturers were slower to recognize the need for standardsCustomers demanded that product was standardization
34 TWO VIEWPOINTS ABOUT STANDARDS
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
People who have a strong networking background see the computer as a tool to enhance a network`s capability
One
Tend to wait for standards and follow them closely
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Figure 3-1 Two different views of the relative roles of networks and computers
Those who have a strong computer background tend to focus on what can be done with software or specially designed circuit chips for computers
They forge ahead of the standards-making process
Two
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Purport While neither viewpoint is wrong it leads to differing philosophiesBoth are legitimate and have their place
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
35 STANDS AND STANDS-MAKING ORGANIZATIONS Because of the recognized need for common international standards there is a great deal of cooperation among communications standards making organizations Data communication standards are more complicated than Voice communication standardsEarly standards were mostly electrical in nature The standards-setting process is slowWriting standards is difficult work
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
ITU (The International Telecommunication Union)
1865 in the U S was established in Paris 1947 as part of the United Nations members from 188 countries headquartered in Geneva SwitzerlandThe most important telecommunications standards-setting organization in the world is the ITU ITU-T has created two sets of standards for the electrical connection of terminals to communications networks
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
ISOInternational Standards OrganizationDonrsquot confuse the OSI with ISO and IOSISO means the international organization for standardizationIOS (internet operation system) is used in CISCO systemrsquos routers and switches
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Figure of the organizations involved in setting telecommunications standards or in passing input to the standards-setting bodies
The American National Standards Institute (ANSI) is not involved in setting communications standards The official TCPIP model is now maintained by the IETFAll communications standards are developed by one organization the ISOF
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
36 V STANDARD XSTANDARD
The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called the V and X standards
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Vstandards define the connection of digital equipment to the PSTN`s analog linesV32 V33 V42 standard for the use of telephone transmission of data made a clear statement XstandardsDefine the connection of digital equipment to digital linesEG X25 X400 X500
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
37 ADVANTAGES AND DISADVANTAGES OF STANDARDS
Adv Standards allow products from multiple vendors to be connected to one another and to communicate
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
disadvanceThe standards-setting process is slowStandards tend to freeze technologyMultiple conflicting standardsThe standards-setting process can occur quickly(Writing standards is relatively easy ) when an architecture is in placeF
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
38 COMMUNICATIONS ARCHITECTURESISO and ITU-T developed OSI reference model in 1978OSI-RM Open Systems Interconnection reference modelThe standards development process took so long that the osi model never came into widespread useIt is the standard reference point by which data communications networks are described
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
39 THE ISO`S OSI REFERENCE MODEL391 Objective Provide a basis for interconnecting dissimilar systems for the purpose of information exchange Define communications rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI and most network architecture use a layered approach A layer in the OSI RM represents a component of the total process of communicating Each one layer requests services from the layer below it N layer Provide services to N+1 layer The same network any two-system must have the same level The actual physical communication completed only in the bottom layer
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1) Layering forces the modularization of function Dealing with complex systemsThe output of laying definition process is standardseases maintenance updating of systemOne layer can be changed without affecting other layersDifferent implementations can be substituted relativelyTransparently
Why layering
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layer Layer requires reasonably sophisticated software and hardware at each end of the connection
前置处理机CCP
中央主机 中央主机中央主机
前置处理机
前置处理机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The philosopher-translator-Secretary architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
CN scientists
CN Translate
CNTelegrafisten
Telex machine
JP scientists
JP Translate
JPTelegrafisten
Telex machine
protocol
protocol
protocol
protocol
Scientific opinion
English
Letters
Telegraph code
Example Scientific exchange layered
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Architecture Layered principle Basic concept
Entity Can send or receive any information of hardware software process Peer layer Two different systems the same level Interface Interaction between the two neighboring layerSERVE for the upper classes a capacity to provide services through the interface Protocol Communication both in communication must comply with the rules
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Network Management and Operation wwwgxmueducn
SYSA
SYSBentity Pee
r layerpeer
entity
server
Physical communication line
Layered network Architecture SYS
B
P3P2P1
2 1
3 2 1
Physical communication line
3
N+1 N N-1
N+1 N N-1Pn-1
Pn
Pn+1
SYSA
interfact
The way that the interaction between the layers actually takes place is that each one requests services from the layer above it
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services The way that the interaction between the layers actually takes place is that each one requests services from the layer above itEach layer provides services to the next higher layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Service PrimitivesPrimitiv
eMeaning
Request An Entity wants the service to do some work
Indication
An Entity is to be informed about an event
Response
An Entity wants to respond to an event
Confirm The Response to an eariler request has come back
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
服务用户( N+1 )
服务提供者( N )系统 A 服务用户
( N+1 )服务提供者
( N )系统 B
无需证实Request
Indication
RequestIndication
Response
Confirm
需证实PDU
Relations among Service Primitives
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
电话系统工作示例例如张三打电话请李四吃饭服务提供者为电话局 ① CONNECT request 张三拨李四的电话号码 ② CONNECT i ndi cati on 李四的电话振铃 ③ CONNECT response 李四摘机 ④ CONNECT confi rm 张三听到振铃停止知道有人应答 ⑤ DATA request 张三说话发出邀请 ⑥ DATA i ndi cati on 李四听到张三的邀请 ⑦ DATA request 李四说话接受邀请 ⑧ DATA i ndi cati on 张三听到李四的答复 ⑨ DI SCONNECT request 李四挂机 ⑩ DI SCONNECT i ndi cat i on 张三听到李四挂机也挂机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Protocols can provide a service for upper layer
Protocols is ldquolevelrdquo But Services is ldquoVertical rdquo Service is adopted by the lower layer of
interface Functions is the internal activities
Services interface protocols and functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services to Protocols Relationship
The relationship between a service and a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layers of the ISOrsquos OSI reference model The layers of the OSI model on each node
communicate with each other
A layer in the OSI model represents a compon-ent of the total process of communicating T
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Actual communication passes down through the layers on the sending node and then up through the layers on the receiving node
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
X25The first three layers of the OSI model have been standardized and together are called the X25 standard for data transmission
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
GOSIP government open system Interconnetion Protocola subset of the OSI model that vendors must support if they want to sell network services or equipment to the US governmentGOSIP is neither a new architecture nor a New standardIt is a more precise specification of what parts of the OSI model the government will use
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipment
What are the Physical Layer components on my computer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
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Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
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A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
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OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Department of Computer Networking Application
CHAPTER 3 Network Architetures and Standarts
DI1 The first section
2 Exercises
3 Online lecture
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Introduction3-1
Definition Architecture3-2
Why have Architecture3-3 3-10
Definition Architecture3-5
The Vand Xstandards3-6
Advs and disadvs of standards3-7
Communication Architecture3-8
ISO Reference Model3-9
Standards making org3-4 Internet Architecture3-11
Manufactures Architecture3-12
A caveat about3-13
Layered architecture3-14
TCPIP Architecture
Network Management and Operation wwwgxmueducn
OBJECTIVESExplain the difference between architectures and standardsExplain the need for network architecture and standardsIdentify a number of communications standards-making orgDescribe the OSI model architectureDescribe TCPIP architectureDescribe the architecture of the InternetDiscuss the ADV and DISADV of layered architecture
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Network Management and Operation wwwgxmueducn
31 IntroductionDefinitions of architectures and standardsThe difference among themThe need of themSpecific example of themExamine adv amp disadv
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Network Management and Operation wwwgxmueducn
32 DEFINITION OF ARCHITECTURES AND STANDARDS
Architecture is a plan or direction that is oriented toward the needs of the userNetwork architecture is a set of principles used as the basic for the design and implementation of a communications network
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It includes the organization of functions that must be performed by the network and the description of data formats and procedures
Network architecture=layer + protocols
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Network architecture features
May or may not conform to standards Donrsquot provides enough detail how network to be implemented Provides a set of generic concepts Most architecture (plan) are designed for the long term use
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Single Layer Model First Communication Between Computer DevicesThe communication and application software be intermingled (To mix)
DEVICE A
Hardwareamp
Software
Hardwareamp
Software
DEVICE B1
The early networks were not flexibleSingle specification for all aspects of communication
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IBM SNA(System Network Architecture)
IBM 1974 by the first computer network architectureIBMrsquos SNA is a proprietary architectureNOTENot SNA(storage area network) Most network architectures developed since use a layered approach
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Network Management and Operation wwwgxmueducn
Communication standardThe rules that are established to ensure compatibility among similar communications products and servicesCommunications standards are the flesh on the architectural skeletonThey specify how a particular communications product serviceor interface will operate
V90 modem
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33 why have network architectures
1Communication system were becoming too complex2 wanted to be isolated from the complexities of the network3Wanted to connect different types of devices to the network4Distributed processing and client-server processing became practical5Network needed to be managed
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BackgroundCommunications vendors realized early standardscomputer manufacturers were slower to recognize the need for standardsCustomers demanded that product was standardization
34 TWO VIEWPOINTS ABOUT STANDARDS
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People who have a strong networking background see the computer as a tool to enhance a network`s capability
One
Tend to wait for standards and follow them closely
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Figure 3-1 Two different views of the relative roles of networks and computers
Those who have a strong computer background tend to focus on what can be done with software or specially designed circuit chips for computers
They forge ahead of the standards-making process
Two
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Purport While neither viewpoint is wrong it leads to differing philosophiesBoth are legitimate and have their place
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35 STANDS AND STANDS-MAKING ORGANIZATIONS Because of the recognized need for common international standards there is a great deal of cooperation among communications standards making organizations Data communication standards are more complicated than Voice communication standardsEarly standards were mostly electrical in nature The standards-setting process is slowWriting standards is difficult work
Chapter 3 Network Architetures and Standarts
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ITU (The International Telecommunication Union)
1865 in the U S was established in Paris 1947 as part of the United Nations members from 188 countries headquartered in Geneva SwitzerlandThe most important telecommunications standards-setting organization in the world is the ITU ITU-T has created two sets of standards for the electrical connection of terminals to communications networks
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
ISOInternational Standards OrganizationDonrsquot confuse the OSI with ISO and IOSISO means the international organization for standardizationIOS (internet operation system) is used in CISCO systemrsquos routers and switches
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Figure of the organizations involved in setting telecommunications standards or in passing input to the standards-setting bodies
The American National Standards Institute (ANSI) is not involved in setting communications standards The official TCPIP model is now maintained by the IETFAll communications standards are developed by one organization the ISOF
Chapter 3 Network Architetures and Standarts
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36 V STANDARD XSTANDARD
The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called the V and X standards
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Vstandards define the connection of digital equipment to the PSTN`s analog linesV32 V33 V42 standard for the use of telephone transmission of data made a clear statement XstandardsDefine the connection of digital equipment to digital linesEG X25 X400 X500
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37 ADVANTAGES AND DISADVANTAGES OF STANDARDS
Adv Standards allow products from multiple vendors to be connected to one another and to communicate
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Network Management and Operation wwwgxmueducn
disadvanceThe standards-setting process is slowStandards tend to freeze technologyMultiple conflicting standardsThe standards-setting process can occur quickly(Writing standards is relatively easy ) when an architecture is in placeF
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38 COMMUNICATIONS ARCHITECTURESISO and ITU-T developed OSI reference model in 1978OSI-RM Open Systems Interconnection reference modelThe standards development process took so long that the osi model never came into widespread useIt is the standard reference point by which data communications networks are described
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39 THE ISO`S OSI REFERENCE MODEL391 Objective Provide a basis for interconnecting dissimilar systems for the purpose of information exchange Define communications rules
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OSI and most network architecture use a layered approach A layer in the OSI RM represents a component of the total process of communicating Each one layer requests services from the layer below it N layer Provide services to N+1 layer The same network any two-system must have the same level The actual physical communication completed only in the bottom layer
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1) Layering forces the modularization of function Dealing with complex systemsThe output of laying definition process is standardseases maintenance updating of systemOne layer can be changed without affecting other layersDifferent implementations can be substituted relativelyTransparently
Why layering
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Layer Layer requires reasonably sophisticated software and hardware at each end of the connection
前置处理机CCP
中央主机 中央主机中央主机
前置处理机
前置处理机
Chapter 3 Network Architetures and Standarts
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The philosopher-translator-Secretary architecture
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Network Management and Operation wwwgxmueducn
CN scientists
CN Translate
CNTelegrafisten
Telex machine
JP scientists
JP Translate
JPTelegrafisten
Telex machine
protocol
protocol
protocol
protocol
Scientific opinion
English
Letters
Telegraph code
Example Scientific exchange layered
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Network Architecture Layered principle Basic concept
Entity Can send or receive any information of hardware software process Peer layer Two different systems the same level Interface Interaction between the two neighboring layerSERVE for the upper classes a capacity to provide services through the interface Protocol Communication both in communication must comply with the rules
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SYSA
SYSBentity Pee
r layerpeer
entity
server
Physical communication line
Layered network Architecture SYS
B
P3P2P1
2 1
3 2 1
Physical communication line
3
N+1 N N-1
N+1 N N-1Pn-1
Pn
Pn+1
SYSA
interfact
The way that the interaction between the layers actually takes place is that each one requests services from the layer above it
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Services The way that the interaction between the layers actually takes place is that each one requests services from the layer above itEach layer provides services to the next higher layer
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Service PrimitivesPrimitiv
eMeaning
Request An Entity wants the service to do some work
Indication
An Entity is to be informed about an event
Response
An Entity wants to respond to an event
Confirm The Response to an eariler request has come back
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服务用户( N+1 )
服务提供者( N )系统 A 服务用户
( N+1 )服务提供者
( N )系统 B
无需证实Request
Indication
RequestIndication
Response
Confirm
需证实PDU
Relations among Service Primitives
Chapter 3 Network Architetures and Standarts
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电话系统工作示例例如张三打电话请李四吃饭服务提供者为电话局 ① CONNECT request 张三拨李四的电话号码 ② CONNECT i ndi cati on 李四的电话振铃 ③ CONNECT response 李四摘机 ④ CONNECT confi rm 张三听到振铃停止知道有人应答 ⑤ DATA request 张三说话发出邀请 ⑥ DATA i ndi cati on 李四听到张三的邀请 ⑦ DATA request 李四说话接受邀请 ⑧ DATA i ndi cati on 张三听到李四的答复 ⑨ DI SCONNECT request 李四挂机 ⑩ DI SCONNECT i ndi cat i on 张三听到李四挂机也挂机
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Protocols can provide a service for upper layer
Protocols is ldquolevelrdquo But Services is ldquoVertical rdquo Service is adopted by the lower layer of
interface Functions is the internal activities
Services interface protocols and functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services to Protocols Relationship
The relationship between a service and a protocol
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Layers of the ISOrsquos OSI reference model The layers of the OSI model on each node
communicate with each other
A layer in the OSI model represents a compon-ent of the total process of communicating T
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Actual communication passes down through the layers on the sending node and then up through the layers on the receiving node
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X25The first three layers of the OSI model have been standardized and together are called the X25 standard for data transmission
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GOSIP government open system Interconnetion Protocola subset of the OSI model that vendors must support if they want to sell network services or equipment to the US governmentGOSIP is neither a new architecture nor a New standardIt is a more precise specification of what parts of the OSI model the government will use
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392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
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Typical equipment
What are the Physical Layer components on my computer
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Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
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LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
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Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
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Network Interface Card Bridge
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LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
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LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
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Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
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LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
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Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
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LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
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Direct and Indirect Methods of Translation Concept of Encryption and Decryption
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Data Compression Methods Run-Length Encoding
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LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
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OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
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Typical equipmentGateway proxy firewall
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Summary of Layer Functions
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OSI 模型是协助网络检修人员识别网络问题一种理想的框架
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310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
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The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
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TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
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A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
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PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
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TCPIP and the OSI Model
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Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
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Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
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UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
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Some Protocols in TCPIP Suite
Internet
Transport
App
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A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
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311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
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The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
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Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
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312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
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IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
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OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
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The ATM reference model
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NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
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Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
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A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
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3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
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3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
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OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
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课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
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Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Introduction3-1
Definition Architecture3-2
Why have Architecture3-3 3-10
Definition Architecture3-5
The Vand Xstandards3-6
Advs and disadvs of standards3-7
Communication Architecture3-8
ISO Reference Model3-9
Standards making org3-4 Internet Architecture3-11
Manufactures Architecture3-12
A caveat about3-13
Layered architecture3-14
TCPIP Architecture
Network Management and Operation wwwgxmueducn
OBJECTIVESExplain the difference between architectures and standardsExplain the need for network architecture and standardsIdentify a number of communications standards-making orgDescribe the OSI model architectureDescribe TCPIP architectureDescribe the architecture of the InternetDiscuss the ADV and DISADV of layered architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
31 IntroductionDefinitions of architectures and standardsThe difference among themThe need of themSpecific example of themExamine adv amp disadv
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Network Management and Operation wwwgxmueducn
32 DEFINITION OF ARCHITECTURES AND STANDARDS
Architecture is a plan or direction that is oriented toward the needs of the userNetwork architecture is a set of principles used as the basic for the design and implementation of a communications network
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
It includes the organization of functions that must be performed by the network and the description of data formats and procedures
Network architecture=layer + protocols
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network architecture features
May or may not conform to standards Donrsquot provides enough detail how network to be implemented Provides a set of generic concepts Most architecture (plan) are designed for the long term use
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Single Layer Model First Communication Between Computer DevicesThe communication and application software be intermingled (To mix)
DEVICE A
Hardwareamp
Software
Hardwareamp
Software
DEVICE B1
The early networks were not flexibleSingle specification for all aspects of communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA(System Network Architecture)
IBM 1974 by the first computer network architectureIBMrsquos SNA is a proprietary architectureNOTENot SNA(storage area network) Most network architectures developed since use a layered approach
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Communication standardThe rules that are established to ensure compatibility among similar communications products and servicesCommunications standards are the flesh on the architectural skeletonThey specify how a particular communications product serviceor interface will operate
V90 modem
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Network Management and Operation wwwgxmueducn
33 why have network architectures
1Communication system were becoming too complex2 wanted to be isolated from the complexities of the network3Wanted to connect different types of devices to the network4Distributed processing and client-server processing became practical5Network needed to be managed
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Network Management and Operation wwwgxmueducn
BackgroundCommunications vendors realized early standardscomputer manufacturers were slower to recognize the need for standardsCustomers demanded that product was standardization
34 TWO VIEWPOINTS ABOUT STANDARDS
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Network Management and Operation wwwgxmueducn
People who have a strong networking background see the computer as a tool to enhance a network`s capability
One
Tend to wait for standards and follow them closely
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Figure 3-1 Two different views of the relative roles of networks and computers
Those who have a strong computer background tend to focus on what can be done with software or specially designed circuit chips for computers
They forge ahead of the standards-making process
Two
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Network Management and Operation wwwgxmueducn
Purport While neither viewpoint is wrong it leads to differing philosophiesBoth are legitimate and have their place
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Network Management and Operation wwwgxmueducn
35 STANDS AND STANDS-MAKING ORGANIZATIONS Because of the recognized need for common international standards there is a great deal of cooperation among communications standards making organizations Data communication standards are more complicated than Voice communication standardsEarly standards were mostly electrical in nature The standards-setting process is slowWriting standards is difficult work
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
ITU (The International Telecommunication Union)
1865 in the U S was established in Paris 1947 as part of the United Nations members from 188 countries headquartered in Geneva SwitzerlandThe most important telecommunications standards-setting organization in the world is the ITU ITU-T has created two sets of standards for the electrical connection of terminals to communications networks
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
ISOInternational Standards OrganizationDonrsquot confuse the OSI with ISO and IOSISO means the international organization for standardizationIOS (internet operation system) is used in CISCO systemrsquos routers and switches
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Figure of the organizations involved in setting telecommunications standards or in passing input to the standards-setting bodies
The American National Standards Institute (ANSI) is not involved in setting communications standards The official TCPIP model is now maintained by the IETFAll communications standards are developed by one organization the ISOF
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
36 V STANDARD XSTANDARD
The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called the V and X standards
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Vstandards define the connection of digital equipment to the PSTN`s analog linesV32 V33 V42 standard for the use of telephone transmission of data made a clear statement XstandardsDefine the connection of digital equipment to digital linesEG X25 X400 X500
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37 ADVANTAGES AND DISADVANTAGES OF STANDARDS
Adv Standards allow products from multiple vendors to be connected to one another and to communicate
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Network Management and Operation wwwgxmueducn
disadvanceThe standards-setting process is slowStandards tend to freeze technologyMultiple conflicting standardsThe standards-setting process can occur quickly(Writing standards is relatively easy ) when an architecture is in placeF
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Network Management and Operation wwwgxmueducn
38 COMMUNICATIONS ARCHITECTURESISO and ITU-T developed OSI reference model in 1978OSI-RM Open Systems Interconnection reference modelThe standards development process took so long that the osi model never came into widespread useIt is the standard reference point by which data communications networks are described
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
39 THE ISO`S OSI REFERENCE MODEL391 Objective Provide a basis for interconnecting dissimilar systems for the purpose of information exchange Define communications rules
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Network Management and Operation wwwgxmueducn
OSI and most network architecture use a layered approach A layer in the OSI RM represents a component of the total process of communicating Each one layer requests services from the layer below it N layer Provide services to N+1 layer The same network any two-system must have the same level The actual physical communication completed only in the bottom layer
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1) Layering forces the modularization of function Dealing with complex systemsThe output of laying definition process is standardseases maintenance updating of systemOne layer can be changed without affecting other layersDifferent implementations can be substituted relativelyTransparently
Why layering
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Network Management and Operation wwwgxmueducn
Layer Layer requires reasonably sophisticated software and hardware at each end of the connection
前置处理机CCP
中央主机 中央主机中央主机
前置处理机
前置处理机
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Network Management and Operation wwwgxmueducn
The philosopher-translator-Secretary architecture
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Network Management and Operation wwwgxmueducn
CN scientists
CN Translate
CNTelegrafisten
Telex machine
JP scientists
JP Translate
JPTelegrafisten
Telex machine
protocol
protocol
protocol
protocol
Scientific opinion
English
Letters
Telegraph code
Example Scientific exchange layered
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Network Management and Operation wwwgxmueducn
Network Architecture Layered principle Basic concept
Entity Can send or receive any information of hardware software process Peer layer Two different systems the same level Interface Interaction between the two neighboring layerSERVE for the upper classes a capacity to provide services through the interface Protocol Communication both in communication must comply with the rules
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SYSA
SYSBentity Pee
r layerpeer
entity
server
Physical communication line
Layered network Architecture SYS
B
P3P2P1
2 1
3 2 1
Physical communication line
3
N+1 N N-1
N+1 N N-1Pn-1
Pn
Pn+1
SYSA
interfact
The way that the interaction between the layers actually takes place is that each one requests services from the layer above it
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Services The way that the interaction between the layers actually takes place is that each one requests services from the layer above itEach layer provides services to the next higher layer
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Service PrimitivesPrimitiv
eMeaning
Request An Entity wants the service to do some work
Indication
An Entity is to be informed about an event
Response
An Entity wants to respond to an event
Confirm The Response to an eariler request has come back
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服务用户( N+1 )
服务提供者( N )系统 A 服务用户
( N+1 )服务提供者
( N )系统 B
无需证实Request
Indication
RequestIndication
Response
Confirm
需证实PDU
Relations among Service Primitives
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Network Management and Operation wwwgxmueducn
电话系统工作示例例如张三打电话请李四吃饭服务提供者为电话局 ① CONNECT request 张三拨李四的电话号码 ② CONNECT i ndi cati on 李四的电话振铃 ③ CONNECT response 李四摘机 ④ CONNECT confi rm 张三听到振铃停止知道有人应答 ⑤ DATA request 张三说话发出邀请 ⑥ DATA i ndi cati on 李四听到张三的邀请 ⑦ DATA request 李四说话接受邀请 ⑧ DATA i ndi cati on 张三听到李四的答复 ⑨ DI SCONNECT request 李四挂机 ⑩ DI SCONNECT i ndi cat i on 张三听到李四挂机也挂机
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Protocols can provide a service for upper layer
Protocols is ldquolevelrdquo But Services is ldquoVertical rdquo Service is adopted by the lower layer of
interface Functions is the internal activities
Services interface protocols and functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services to Protocols Relationship
The relationship between a service and a protocol
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Network Management and Operation wwwgxmueducn
Layers of the ISOrsquos OSI reference model The layers of the OSI model on each node
communicate with each other
A layer in the OSI model represents a compon-ent of the total process of communicating T
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Actual communication passes down through the layers on the sending node and then up through the layers on the receiving node
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X25The first three layers of the OSI model have been standardized and together are called the X25 standard for data transmission
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GOSIP government open system Interconnetion Protocola subset of the OSI model that vendors must support if they want to sell network services or equipment to the US governmentGOSIP is neither a new architecture nor a New standardIt is a more precise specification of what parts of the OSI model the government will use
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392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
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Typical equipment
What are the Physical Layer components on my computer
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Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
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LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
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Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
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Network Interface Card Bridge
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LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
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LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
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Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
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LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
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Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
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LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
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Direct and Indirect Methods of Translation Concept of Encryption and Decryption
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Data Compression Methods Run-Length Encoding
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LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
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OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
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Typical equipmentGateway proxy firewall
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Summary of Layer Functions
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OSI 模型是协助网络检修人员识别网络问题一种理想的框架
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310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
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The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
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TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
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A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
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PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
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TCPIP and the OSI Model
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Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
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Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
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UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
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Some Protocols in TCPIP Suite
Internet
Transport
App
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A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
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311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
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The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
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Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
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312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
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IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
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OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
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The ATM reference model
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NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
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Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
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A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
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3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
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3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
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OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
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Network Management and Operation wwwgxmueducn
OBJECTIVESExplain the difference between architectures and standardsExplain the need for network architecture and standardsIdentify a number of communications standards-making orgDescribe the OSI model architectureDescribe TCPIP architectureDescribe the architecture of the InternetDiscuss the ADV and DISADV of layered architecture
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31 IntroductionDefinitions of architectures and standardsThe difference among themThe need of themSpecific example of themExamine adv amp disadv
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32 DEFINITION OF ARCHITECTURES AND STANDARDS
Architecture is a plan or direction that is oriented toward the needs of the userNetwork architecture is a set of principles used as the basic for the design and implementation of a communications network
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It includes the organization of functions that must be performed by the network and the description of data formats and procedures
Network architecture=layer + protocols
Chapter 3 Network Architetures and Standarts
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Network architecture features
May or may not conform to standards Donrsquot provides enough detail how network to be implemented Provides a set of generic concepts Most architecture (plan) are designed for the long term use
Chapter 3 Network Architetures and Standarts
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Single Layer Model First Communication Between Computer DevicesThe communication and application software be intermingled (To mix)
DEVICE A
Hardwareamp
Software
Hardwareamp
Software
DEVICE B1
The early networks were not flexibleSingle specification for all aspects of communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA(System Network Architecture)
IBM 1974 by the first computer network architectureIBMrsquos SNA is a proprietary architectureNOTENot SNA(storage area network) Most network architectures developed since use a layered approach
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Communication standardThe rules that are established to ensure compatibility among similar communications products and servicesCommunications standards are the flesh on the architectural skeletonThey specify how a particular communications product serviceor interface will operate
V90 modem
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33 why have network architectures
1Communication system were becoming too complex2 wanted to be isolated from the complexities of the network3Wanted to connect different types of devices to the network4Distributed processing and client-server processing became practical5Network needed to be managed
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
BackgroundCommunications vendors realized early standardscomputer manufacturers were slower to recognize the need for standardsCustomers demanded that product was standardization
34 TWO VIEWPOINTS ABOUT STANDARDS
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
People who have a strong networking background see the computer as a tool to enhance a network`s capability
One
Tend to wait for standards and follow them closely
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Figure 3-1 Two different views of the relative roles of networks and computers
Those who have a strong computer background tend to focus on what can be done with software or specially designed circuit chips for computers
They forge ahead of the standards-making process
Two
Chapter 3 Network Architetures and Standarts
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Purport While neither viewpoint is wrong it leads to differing philosophiesBoth are legitimate and have their place
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
35 STANDS AND STANDS-MAKING ORGANIZATIONS Because of the recognized need for common international standards there is a great deal of cooperation among communications standards making organizations Data communication standards are more complicated than Voice communication standardsEarly standards were mostly electrical in nature The standards-setting process is slowWriting standards is difficult work
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
ITU (The International Telecommunication Union)
1865 in the U S was established in Paris 1947 as part of the United Nations members from 188 countries headquartered in Geneva SwitzerlandThe most important telecommunications standards-setting organization in the world is the ITU ITU-T has created two sets of standards for the electrical connection of terminals to communications networks
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
ISOInternational Standards OrganizationDonrsquot confuse the OSI with ISO and IOSISO means the international organization for standardizationIOS (internet operation system) is used in CISCO systemrsquos routers and switches
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Figure of the organizations involved in setting telecommunications standards or in passing input to the standards-setting bodies
The American National Standards Institute (ANSI) is not involved in setting communications standards The official TCPIP model is now maintained by the IETFAll communications standards are developed by one organization the ISOF
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Network Management and Operation wwwgxmueducn
36 V STANDARD XSTANDARD
The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called the V and X standards
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Vstandards define the connection of digital equipment to the PSTN`s analog linesV32 V33 V42 standard for the use of telephone transmission of data made a clear statement XstandardsDefine the connection of digital equipment to digital linesEG X25 X400 X500
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37 ADVANTAGES AND DISADVANTAGES OF STANDARDS
Adv Standards allow products from multiple vendors to be connected to one another and to communicate
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Network Management and Operation wwwgxmueducn
disadvanceThe standards-setting process is slowStandards tend to freeze technologyMultiple conflicting standardsThe standards-setting process can occur quickly(Writing standards is relatively easy ) when an architecture is in placeF
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Network Management and Operation wwwgxmueducn
38 COMMUNICATIONS ARCHITECTURESISO and ITU-T developed OSI reference model in 1978OSI-RM Open Systems Interconnection reference modelThe standards development process took so long that the osi model never came into widespread useIt is the standard reference point by which data communications networks are described
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Network Management and Operation wwwgxmueducn
39 THE ISO`S OSI REFERENCE MODEL391 Objective Provide a basis for interconnecting dissimilar systems for the purpose of information exchange Define communications rules
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Network Management and Operation wwwgxmueducn
OSI and most network architecture use a layered approach A layer in the OSI RM represents a component of the total process of communicating Each one layer requests services from the layer below it N layer Provide services to N+1 layer The same network any two-system must have the same level The actual physical communication completed only in the bottom layer
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1) Layering forces the modularization of function Dealing with complex systemsThe output of laying definition process is standardseases maintenance updating of systemOne layer can be changed without affecting other layersDifferent implementations can be substituted relativelyTransparently
Why layering
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Network Management and Operation wwwgxmueducn
Layer Layer requires reasonably sophisticated software and hardware at each end of the connection
前置处理机CCP
中央主机 中央主机中央主机
前置处理机
前置处理机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The philosopher-translator-Secretary architecture
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Network Management and Operation wwwgxmueducn
CN scientists
CN Translate
CNTelegrafisten
Telex machine
JP scientists
JP Translate
JPTelegrafisten
Telex machine
protocol
protocol
protocol
protocol
Scientific opinion
English
Letters
Telegraph code
Example Scientific exchange layered
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Network Management and Operation wwwgxmueducn
Network Architecture Layered principle Basic concept
Entity Can send or receive any information of hardware software process Peer layer Two different systems the same level Interface Interaction between the two neighboring layerSERVE for the upper classes a capacity to provide services through the interface Protocol Communication both in communication must comply with the rules
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SYSA
SYSBentity Pee
r layerpeer
entity
server
Physical communication line
Layered network Architecture SYS
B
P3P2P1
2 1
3 2 1
Physical communication line
3
N+1 N N-1
N+1 N N-1Pn-1
Pn
Pn+1
SYSA
interfact
The way that the interaction between the layers actually takes place is that each one requests services from the layer above it
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Network Management and Operation wwwgxmueducn
Services The way that the interaction between the layers actually takes place is that each one requests services from the layer above itEach layer provides services to the next higher layer
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Service PrimitivesPrimitiv
eMeaning
Request An Entity wants the service to do some work
Indication
An Entity is to be informed about an event
Response
An Entity wants to respond to an event
Confirm The Response to an eariler request has come back
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服务用户( N+1 )
服务提供者( N )系统 A 服务用户
( N+1 )服务提供者
( N )系统 B
无需证实Request
Indication
RequestIndication
Response
Confirm
需证实PDU
Relations among Service Primitives
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Network Management and Operation wwwgxmueducn
电话系统工作示例例如张三打电话请李四吃饭服务提供者为电话局 ① CONNECT request 张三拨李四的电话号码 ② CONNECT i ndi cati on 李四的电话振铃 ③ CONNECT response 李四摘机 ④ CONNECT confi rm 张三听到振铃停止知道有人应答 ⑤ DATA request 张三说话发出邀请 ⑥ DATA i ndi cati on 李四听到张三的邀请 ⑦ DATA request 李四说话接受邀请 ⑧ DATA i ndi cati on 张三听到李四的答复 ⑨ DI SCONNECT request 李四挂机 ⑩ DI SCONNECT i ndi cat i on 张三听到李四挂机也挂机
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Network Management and Operation wwwgxmueducn
Protocols can provide a service for upper layer
Protocols is ldquolevelrdquo But Services is ldquoVertical rdquo Service is adopted by the lower layer of
interface Functions is the internal activities
Services interface protocols and functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services to Protocols Relationship
The relationship between a service and a protocol
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Network Management and Operation wwwgxmueducn
Layers of the ISOrsquos OSI reference model The layers of the OSI model on each node
communicate with each other
A layer in the OSI model represents a compon-ent of the total process of communicating T
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Actual communication passes down through the layers on the sending node and then up through the layers on the receiving node
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X25The first three layers of the OSI model have been standardized and together are called the X25 standard for data transmission
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GOSIP government open system Interconnetion Protocola subset of the OSI model that vendors must support if they want to sell network services or equipment to the US governmentGOSIP is neither a new architecture nor a New standardIt is a more precise specification of what parts of the OSI model the government will use
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392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
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Typical equipment
What are the Physical Layer components on my computer
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Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
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LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
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Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
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Network Interface Card Bridge
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LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
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LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
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Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
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LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
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Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
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LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
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Direct and Indirect Methods of Translation Concept of Encryption and Decryption
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Data Compression Methods Run-Length Encoding
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LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
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OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
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Typical equipmentGateway proxy firewall
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Summary of Layer Functions
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OSI 模型是协助网络检修人员识别网络问题一种理想的框架
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310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
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The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
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TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
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A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
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PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
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TCPIP and the OSI Model
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Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
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Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
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UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
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Some Protocols in TCPIP Suite
Internet
Transport
App
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A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
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311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
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The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
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Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
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312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
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IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
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OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
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The ATM reference model
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NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
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Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
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A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
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3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
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3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
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OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
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课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
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Network Management and Operation wwwgxmueducn
31 IntroductionDefinitions of architectures and standardsThe difference among themThe need of themSpecific example of themExamine adv amp disadv
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32 DEFINITION OF ARCHITECTURES AND STANDARDS
Architecture is a plan or direction that is oriented toward the needs of the userNetwork architecture is a set of principles used as the basic for the design and implementation of a communications network
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It includes the organization of functions that must be performed by the network and the description of data formats and procedures
Network architecture=layer + protocols
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Network architecture features
May or may not conform to standards Donrsquot provides enough detail how network to be implemented Provides a set of generic concepts Most architecture (plan) are designed for the long term use
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Single Layer Model First Communication Between Computer DevicesThe communication and application software be intermingled (To mix)
DEVICE A
Hardwareamp
Software
Hardwareamp
Software
DEVICE B1
The early networks were not flexibleSingle specification for all aspects of communication
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IBM SNA(System Network Architecture)
IBM 1974 by the first computer network architectureIBMrsquos SNA is a proprietary architectureNOTENot SNA(storage area network) Most network architectures developed since use a layered approach
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Communication standardThe rules that are established to ensure compatibility among similar communications products and servicesCommunications standards are the flesh on the architectural skeletonThey specify how a particular communications product serviceor interface will operate
V90 modem
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33 why have network architectures
1Communication system were becoming too complex2 wanted to be isolated from the complexities of the network3Wanted to connect different types of devices to the network4Distributed processing and client-server processing became practical5Network needed to be managed
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BackgroundCommunications vendors realized early standardscomputer manufacturers were slower to recognize the need for standardsCustomers demanded that product was standardization
34 TWO VIEWPOINTS ABOUT STANDARDS
Chapter 3 Network Architetures and Standarts
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People who have a strong networking background see the computer as a tool to enhance a network`s capability
One
Tend to wait for standards and follow them closely
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Figure 3-1 Two different views of the relative roles of networks and computers
Those who have a strong computer background tend to focus on what can be done with software or specially designed circuit chips for computers
They forge ahead of the standards-making process
Two
Chapter 3 Network Architetures and Standarts
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Purport While neither viewpoint is wrong it leads to differing philosophiesBoth are legitimate and have their place
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35 STANDS AND STANDS-MAKING ORGANIZATIONS Because of the recognized need for common international standards there is a great deal of cooperation among communications standards making organizations Data communication standards are more complicated than Voice communication standardsEarly standards were mostly electrical in nature The standards-setting process is slowWriting standards is difficult work
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
ITU (The International Telecommunication Union)
1865 in the U S was established in Paris 1947 as part of the United Nations members from 188 countries headquartered in Geneva SwitzerlandThe most important telecommunications standards-setting organization in the world is the ITU ITU-T has created two sets of standards for the electrical connection of terminals to communications networks
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
ISOInternational Standards OrganizationDonrsquot confuse the OSI with ISO and IOSISO means the international organization for standardizationIOS (internet operation system) is used in CISCO systemrsquos routers and switches
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Figure of the organizations involved in setting telecommunications standards or in passing input to the standards-setting bodies
The American National Standards Institute (ANSI) is not involved in setting communications standards The official TCPIP model is now maintained by the IETFAll communications standards are developed by one organization the ISOF
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
36 V STANDARD XSTANDARD
The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called the V and X standards
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Vstandards define the connection of digital equipment to the PSTN`s analog linesV32 V33 V42 standard for the use of telephone transmission of data made a clear statement XstandardsDefine the connection of digital equipment to digital linesEG X25 X400 X500
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
37 ADVANTAGES AND DISADVANTAGES OF STANDARDS
Adv Standards allow products from multiple vendors to be connected to one another and to communicate
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
disadvanceThe standards-setting process is slowStandards tend to freeze technologyMultiple conflicting standardsThe standards-setting process can occur quickly(Writing standards is relatively easy ) when an architecture is in placeF
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Network Management and Operation wwwgxmueducn
38 COMMUNICATIONS ARCHITECTURESISO and ITU-T developed OSI reference model in 1978OSI-RM Open Systems Interconnection reference modelThe standards development process took so long that the osi model never came into widespread useIt is the standard reference point by which data communications networks are described
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39 THE ISO`S OSI REFERENCE MODEL391 Objective Provide a basis for interconnecting dissimilar systems for the purpose of information exchange Define communications rules
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OSI and most network architecture use a layered approach A layer in the OSI RM represents a component of the total process of communicating Each one layer requests services from the layer below it N layer Provide services to N+1 layer The same network any two-system must have the same level The actual physical communication completed only in the bottom layer
Chapter 3 Network Architetures and Standarts
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1) Layering forces the modularization of function Dealing with complex systemsThe output of laying definition process is standardseases maintenance updating of systemOne layer can be changed without affecting other layersDifferent implementations can be substituted relativelyTransparently
Why layering
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layer Layer requires reasonably sophisticated software and hardware at each end of the connection
前置处理机CCP
中央主机 中央主机中央主机
前置处理机
前置处理机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The philosopher-translator-Secretary architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
CN scientists
CN Translate
CNTelegrafisten
Telex machine
JP scientists
JP Translate
JPTelegrafisten
Telex machine
protocol
protocol
protocol
protocol
Scientific opinion
English
Letters
Telegraph code
Example Scientific exchange layered
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Architecture Layered principle Basic concept
Entity Can send or receive any information of hardware software process Peer layer Two different systems the same level Interface Interaction between the two neighboring layerSERVE for the upper classes a capacity to provide services through the interface Protocol Communication both in communication must comply with the rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
SYSA
SYSBentity Pee
r layerpeer
entity
server
Physical communication line
Layered network Architecture SYS
B
P3P2P1
2 1
3 2 1
Physical communication line
3
N+1 N N-1
N+1 N N-1Pn-1
Pn
Pn+1
SYSA
interfact
The way that the interaction between the layers actually takes place is that each one requests services from the layer above it
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services The way that the interaction between the layers actually takes place is that each one requests services from the layer above itEach layer provides services to the next higher layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Service PrimitivesPrimitiv
eMeaning
Request An Entity wants the service to do some work
Indication
An Entity is to be informed about an event
Response
An Entity wants to respond to an event
Confirm The Response to an eariler request has come back
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Network Management and Operation wwwgxmueducn
服务用户( N+1 )
服务提供者( N )系统 A 服务用户
( N+1 )服务提供者
( N )系统 B
无需证实Request
Indication
RequestIndication
Response
Confirm
需证实PDU
Relations among Service Primitives
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
电话系统工作示例例如张三打电话请李四吃饭服务提供者为电话局 ① CONNECT request 张三拨李四的电话号码 ② CONNECT i ndi cati on 李四的电话振铃 ③ CONNECT response 李四摘机 ④ CONNECT confi rm 张三听到振铃停止知道有人应答 ⑤ DATA request 张三说话发出邀请 ⑥ DATA i ndi cati on 李四听到张三的邀请 ⑦ DATA request 李四说话接受邀请 ⑧ DATA i ndi cati on 张三听到李四的答复 ⑨ DI SCONNECT request 李四挂机 ⑩ DI SCONNECT i ndi cat i on 张三听到李四挂机也挂机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Protocols can provide a service for upper layer
Protocols is ldquolevelrdquo But Services is ldquoVertical rdquo Service is adopted by the lower layer of
interface Functions is the internal activities
Services interface protocols and functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services to Protocols Relationship
The relationship between a service and a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layers of the ISOrsquos OSI reference model The layers of the OSI model on each node
communicate with each other
A layer in the OSI model represents a compon-ent of the total process of communicating T
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Actual communication passes down through the layers on the sending node and then up through the layers on the receiving node
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
X25The first three layers of the OSI model have been standardized and together are called the X25 standard for data transmission
Chapter 3 Network Architetures and Standarts
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GOSIP government open system Interconnetion Protocola subset of the OSI model that vendors must support if they want to sell network services or equipment to the US governmentGOSIP is neither a new architecture nor a New standardIt is a more precise specification of what parts of the OSI model the government will use
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392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
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Network Management and Operation wwwgxmueducn
Typical equipment
What are the Physical Layer components on my computer
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Network Management and Operation wwwgxmueducn
Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
Chapter 3 Network Architetures and Standarts
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Network Management and Operation wwwgxmueducn
LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
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Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
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Network Interface Card Bridge
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LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
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LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
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Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
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LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
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Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
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LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
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Direct and Indirect Methods of Translation Concept of Encryption and Decryption
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Data Compression Methods Run-Length Encoding
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LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
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OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
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Typical equipmentGateway proxy firewall
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Summary of Layer Functions
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OSI 模型是协助网络检修人员识别网络问题一种理想的框架
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310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
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The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
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TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
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A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
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PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
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TCPIP and the OSI Model
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Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
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Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
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UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
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Some Protocols in TCPIP Suite
Internet
Transport
App
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A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
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Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
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The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
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Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
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312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
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IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
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OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
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The ATM reference model
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NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
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Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
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A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
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3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
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3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
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OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
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课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
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Network Management and Operation wwwgxmueducn
32 DEFINITION OF ARCHITECTURES AND STANDARDS
Architecture is a plan or direction that is oriented toward the needs of the userNetwork architecture is a set of principles used as the basic for the design and implementation of a communications network
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It includes the organization of functions that must be performed by the network and the description of data formats and procedures
Network architecture=layer + protocols
Chapter 3 Network Architetures and Standarts
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Network architecture features
May or may not conform to standards Donrsquot provides enough detail how network to be implemented Provides a set of generic concepts Most architecture (plan) are designed for the long term use
Chapter 3 Network Architetures and Standarts
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Single Layer Model First Communication Between Computer DevicesThe communication and application software be intermingled (To mix)
DEVICE A
Hardwareamp
Software
Hardwareamp
Software
DEVICE B1
The early networks were not flexibleSingle specification for all aspects of communication
Chapter 3 Network Architetures and Standarts
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IBM SNA(System Network Architecture)
IBM 1974 by the first computer network architectureIBMrsquos SNA is a proprietary architectureNOTENot SNA(storage area network) Most network architectures developed since use a layered approach
Chapter 3 Network Architetures and Standarts
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Communication standardThe rules that are established to ensure compatibility among similar communications products and servicesCommunications standards are the flesh on the architectural skeletonThey specify how a particular communications product serviceor interface will operate
V90 modem
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33 why have network architectures
1Communication system were becoming too complex2 wanted to be isolated from the complexities of the network3Wanted to connect different types of devices to the network4Distributed processing and client-server processing became practical5Network needed to be managed
Chapter 3 Network Architetures and Standarts
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BackgroundCommunications vendors realized early standardscomputer manufacturers were slower to recognize the need for standardsCustomers demanded that product was standardization
34 TWO VIEWPOINTS ABOUT STANDARDS
Chapter 3 Network Architetures and Standarts
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People who have a strong networking background see the computer as a tool to enhance a network`s capability
One
Tend to wait for standards and follow them closely
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Figure 3-1 Two different views of the relative roles of networks and computers
Those who have a strong computer background tend to focus on what can be done with software or specially designed circuit chips for computers
They forge ahead of the standards-making process
Two
Chapter 3 Network Architetures and Standarts
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Purport While neither viewpoint is wrong it leads to differing philosophiesBoth are legitimate and have their place
Chapter 3 Network Architetures and Standarts
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35 STANDS AND STANDS-MAKING ORGANIZATIONS Because of the recognized need for common international standards there is a great deal of cooperation among communications standards making organizations Data communication standards are more complicated than Voice communication standardsEarly standards were mostly electrical in nature The standards-setting process is slowWriting standards is difficult work
Chapter 3 Network Architetures and Standarts
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ITU (The International Telecommunication Union)
1865 in the U S was established in Paris 1947 as part of the United Nations members from 188 countries headquartered in Geneva SwitzerlandThe most important telecommunications standards-setting organization in the world is the ITU ITU-T has created two sets of standards for the electrical connection of terminals to communications networks
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
ISOInternational Standards OrganizationDonrsquot confuse the OSI with ISO and IOSISO means the international organization for standardizationIOS (internet operation system) is used in CISCO systemrsquos routers and switches
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Figure of the organizations involved in setting telecommunications standards or in passing input to the standards-setting bodies
The American National Standards Institute (ANSI) is not involved in setting communications standards The official TCPIP model is now maintained by the IETFAll communications standards are developed by one organization the ISOF
Chapter 3 Network Architetures and Standarts
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36 V STANDARD XSTANDARD
The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called the V and X standards
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Vstandards define the connection of digital equipment to the PSTN`s analog linesV32 V33 V42 standard for the use of telephone transmission of data made a clear statement XstandardsDefine the connection of digital equipment to digital linesEG X25 X400 X500
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
37 ADVANTAGES AND DISADVANTAGES OF STANDARDS
Adv Standards allow products from multiple vendors to be connected to one another and to communicate
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
disadvanceThe standards-setting process is slowStandards tend to freeze technologyMultiple conflicting standardsThe standards-setting process can occur quickly(Writing standards is relatively easy ) when an architecture is in placeF
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38 COMMUNICATIONS ARCHITECTURESISO and ITU-T developed OSI reference model in 1978OSI-RM Open Systems Interconnection reference modelThe standards development process took so long that the osi model never came into widespread useIt is the standard reference point by which data communications networks are described
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
39 THE ISO`S OSI REFERENCE MODEL391 Objective Provide a basis for interconnecting dissimilar systems for the purpose of information exchange Define communications rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI and most network architecture use a layered approach A layer in the OSI RM represents a component of the total process of communicating Each one layer requests services from the layer below it N layer Provide services to N+1 layer The same network any two-system must have the same level The actual physical communication completed only in the bottom layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
1) Layering forces the modularization of function Dealing with complex systemsThe output of laying definition process is standardseases maintenance updating of systemOne layer can be changed without affecting other layersDifferent implementations can be substituted relativelyTransparently
Why layering
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layer Layer requires reasonably sophisticated software and hardware at each end of the connection
前置处理机CCP
中央主机 中央主机中央主机
前置处理机
前置处理机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The philosopher-translator-Secretary architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
CN scientists
CN Translate
CNTelegrafisten
Telex machine
JP scientists
JP Translate
JPTelegrafisten
Telex machine
protocol
protocol
protocol
protocol
Scientific opinion
English
Letters
Telegraph code
Example Scientific exchange layered
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Architecture Layered principle Basic concept
Entity Can send or receive any information of hardware software process Peer layer Two different systems the same level Interface Interaction between the two neighboring layerSERVE for the upper classes a capacity to provide services through the interface Protocol Communication both in communication must comply with the rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
SYSA
SYSBentity Pee
r layerpeer
entity
server
Physical communication line
Layered network Architecture SYS
B
P3P2P1
2 1
3 2 1
Physical communication line
3
N+1 N N-1
N+1 N N-1Pn-1
Pn
Pn+1
SYSA
interfact
The way that the interaction between the layers actually takes place is that each one requests services from the layer above it
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services The way that the interaction between the layers actually takes place is that each one requests services from the layer above itEach layer provides services to the next higher layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Service PrimitivesPrimitiv
eMeaning
Request An Entity wants the service to do some work
Indication
An Entity is to be informed about an event
Response
An Entity wants to respond to an event
Confirm The Response to an eariler request has come back
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
服务用户( N+1 )
服务提供者( N )系统 A 服务用户
( N+1 )服务提供者
( N )系统 B
无需证实Request
Indication
RequestIndication
Response
Confirm
需证实PDU
Relations among Service Primitives
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
电话系统工作示例例如张三打电话请李四吃饭服务提供者为电话局 ① CONNECT request 张三拨李四的电话号码 ② CONNECT i ndi cati on 李四的电话振铃 ③ CONNECT response 李四摘机 ④ CONNECT confi rm 张三听到振铃停止知道有人应答 ⑤ DATA request 张三说话发出邀请 ⑥ DATA i ndi cati on 李四听到张三的邀请 ⑦ DATA request 李四说话接受邀请 ⑧ DATA i ndi cati on 张三听到李四的答复 ⑨ DI SCONNECT request 李四挂机 ⑩ DI SCONNECT i ndi cat i on 张三听到李四挂机也挂机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Protocols can provide a service for upper layer
Protocols is ldquolevelrdquo But Services is ldquoVertical rdquo Service is adopted by the lower layer of
interface Functions is the internal activities
Services interface protocols and functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services to Protocols Relationship
The relationship between a service and a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layers of the ISOrsquos OSI reference model The layers of the OSI model on each node
communicate with each other
A layer in the OSI model represents a compon-ent of the total process of communicating T
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Actual communication passes down through the layers on the sending node and then up through the layers on the receiving node
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
X25The first three layers of the OSI model have been standardized and together are called the X25 standard for data transmission
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
GOSIP government open system Interconnetion Protocola subset of the OSI model that vendors must support if they want to sell network services or equipment to the US governmentGOSIP is neither a new architecture nor a New standardIt is a more precise specification of what parts of the OSI model the government will use
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipment
What are the Physical Layer components on my computer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
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IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
It includes the organization of functions that must be performed by the network and the description of data formats and procedures
Network architecture=layer + protocols
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network architecture features
May or may not conform to standards Donrsquot provides enough detail how network to be implemented Provides a set of generic concepts Most architecture (plan) are designed for the long term use
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Single Layer Model First Communication Between Computer DevicesThe communication and application software be intermingled (To mix)
DEVICE A
Hardwareamp
Software
Hardwareamp
Software
DEVICE B1
The early networks were not flexibleSingle specification for all aspects of communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA(System Network Architecture)
IBM 1974 by the first computer network architectureIBMrsquos SNA is a proprietary architectureNOTENot SNA(storage area network) Most network architectures developed since use a layered approach
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Communication standardThe rules that are established to ensure compatibility among similar communications products and servicesCommunications standards are the flesh on the architectural skeletonThey specify how a particular communications product serviceor interface will operate
V90 modem
Chapter 3 Network Architetures and Standarts
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33 why have network architectures
1Communication system were becoming too complex2 wanted to be isolated from the complexities of the network3Wanted to connect different types of devices to the network4Distributed processing and client-server processing became practical5Network needed to be managed
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
BackgroundCommunications vendors realized early standardscomputer manufacturers were slower to recognize the need for standardsCustomers demanded that product was standardization
34 TWO VIEWPOINTS ABOUT STANDARDS
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
People who have a strong networking background see the computer as a tool to enhance a network`s capability
One
Tend to wait for standards and follow them closely
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Figure 3-1 Two different views of the relative roles of networks and computers
Those who have a strong computer background tend to focus on what can be done with software or specially designed circuit chips for computers
They forge ahead of the standards-making process
Two
Chapter 3 Network Architetures and Standarts
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Purport While neither viewpoint is wrong it leads to differing philosophiesBoth are legitimate and have their place
Chapter 3 Network Architetures and Standarts
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35 STANDS AND STANDS-MAKING ORGANIZATIONS Because of the recognized need for common international standards there is a great deal of cooperation among communications standards making organizations Data communication standards are more complicated than Voice communication standardsEarly standards were mostly electrical in nature The standards-setting process is slowWriting standards is difficult work
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
ITU (The International Telecommunication Union)
1865 in the U S was established in Paris 1947 as part of the United Nations members from 188 countries headquartered in Geneva SwitzerlandThe most important telecommunications standards-setting organization in the world is the ITU ITU-T has created two sets of standards for the electrical connection of terminals to communications networks
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
ISOInternational Standards OrganizationDonrsquot confuse the OSI with ISO and IOSISO means the international organization for standardizationIOS (internet operation system) is used in CISCO systemrsquos routers and switches
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Figure of the organizations involved in setting telecommunications standards or in passing input to the standards-setting bodies
The American National Standards Institute (ANSI) is not involved in setting communications standards The official TCPIP model is now maintained by the IETFAll communications standards are developed by one organization the ISOF
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
36 V STANDARD XSTANDARD
The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called the V and X standards
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Vstandards define the connection of digital equipment to the PSTN`s analog linesV32 V33 V42 standard for the use of telephone transmission of data made a clear statement XstandardsDefine the connection of digital equipment to digital linesEG X25 X400 X500
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
37 ADVANTAGES AND DISADVANTAGES OF STANDARDS
Adv Standards allow products from multiple vendors to be connected to one another and to communicate
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
disadvanceThe standards-setting process is slowStandards tend to freeze technologyMultiple conflicting standardsThe standards-setting process can occur quickly(Writing standards is relatively easy ) when an architecture is in placeF
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
38 COMMUNICATIONS ARCHITECTURESISO and ITU-T developed OSI reference model in 1978OSI-RM Open Systems Interconnection reference modelThe standards development process took so long that the osi model never came into widespread useIt is the standard reference point by which data communications networks are described
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
39 THE ISO`S OSI REFERENCE MODEL391 Objective Provide a basis for interconnecting dissimilar systems for the purpose of information exchange Define communications rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI and most network architecture use a layered approach A layer in the OSI RM represents a component of the total process of communicating Each one layer requests services from the layer below it N layer Provide services to N+1 layer The same network any two-system must have the same level The actual physical communication completed only in the bottom layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
1) Layering forces the modularization of function Dealing with complex systemsThe output of laying definition process is standardseases maintenance updating of systemOne layer can be changed without affecting other layersDifferent implementations can be substituted relativelyTransparently
Why layering
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layer Layer requires reasonably sophisticated software and hardware at each end of the connection
前置处理机CCP
中央主机 中央主机中央主机
前置处理机
前置处理机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The philosopher-translator-Secretary architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
CN scientists
CN Translate
CNTelegrafisten
Telex machine
JP scientists
JP Translate
JPTelegrafisten
Telex machine
protocol
protocol
protocol
protocol
Scientific opinion
English
Letters
Telegraph code
Example Scientific exchange layered
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Architecture Layered principle Basic concept
Entity Can send or receive any information of hardware software process Peer layer Two different systems the same level Interface Interaction between the two neighboring layerSERVE for the upper classes a capacity to provide services through the interface Protocol Communication both in communication must comply with the rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
SYSA
SYSBentity Pee
r layerpeer
entity
server
Physical communication line
Layered network Architecture SYS
B
P3P2P1
2 1
3 2 1
Physical communication line
3
N+1 N N-1
N+1 N N-1Pn-1
Pn
Pn+1
SYSA
interfact
The way that the interaction between the layers actually takes place is that each one requests services from the layer above it
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services The way that the interaction between the layers actually takes place is that each one requests services from the layer above itEach layer provides services to the next higher layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Service PrimitivesPrimitiv
eMeaning
Request An Entity wants the service to do some work
Indication
An Entity is to be informed about an event
Response
An Entity wants to respond to an event
Confirm The Response to an eariler request has come back
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
服务用户( N+1 )
服务提供者( N )系统 A 服务用户
( N+1 )服务提供者
( N )系统 B
无需证实Request
Indication
RequestIndication
Response
Confirm
需证实PDU
Relations among Service Primitives
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
电话系统工作示例例如张三打电话请李四吃饭服务提供者为电话局 ① CONNECT request 张三拨李四的电话号码 ② CONNECT i ndi cati on 李四的电话振铃 ③ CONNECT response 李四摘机 ④ CONNECT confi rm 张三听到振铃停止知道有人应答 ⑤ DATA request 张三说话发出邀请 ⑥ DATA i ndi cati on 李四听到张三的邀请 ⑦ DATA request 李四说话接受邀请 ⑧ DATA i ndi cati on 张三听到李四的答复 ⑨ DI SCONNECT request 李四挂机 ⑩ DI SCONNECT i ndi cat i on 张三听到李四挂机也挂机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Protocols can provide a service for upper layer
Protocols is ldquolevelrdquo But Services is ldquoVertical rdquo Service is adopted by the lower layer of
interface Functions is the internal activities
Services interface protocols and functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services to Protocols Relationship
The relationship between a service and a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layers of the ISOrsquos OSI reference model The layers of the OSI model on each node
communicate with each other
A layer in the OSI model represents a compon-ent of the total process of communicating T
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Actual communication passes down through the layers on the sending node and then up through the layers on the receiving node
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
X25The first three layers of the OSI model have been standardized and together are called the X25 standard for data transmission
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
GOSIP government open system Interconnetion Protocola subset of the OSI model that vendors must support if they want to sell network services or equipment to the US governmentGOSIP is neither a new architecture nor a New standardIt is a more precise specification of what parts of the OSI model the government will use
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipment
What are the Physical Layer components on my computer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
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Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
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Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
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Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
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Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
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Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
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IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
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OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
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The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
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Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
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A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
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3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
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3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
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OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
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Network Management and Operation wwwgxmueducn
Network architecture features
May or may not conform to standards Donrsquot provides enough detail how network to be implemented Provides a set of generic concepts Most architecture (plan) are designed for the long term use
Chapter 3 Network Architetures and Standarts
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Single Layer Model First Communication Between Computer DevicesThe communication and application software be intermingled (To mix)
DEVICE A
Hardwareamp
Software
Hardwareamp
Software
DEVICE B1
The early networks were not flexibleSingle specification for all aspects of communication
Chapter 3 Network Architetures and Standarts
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IBM SNA(System Network Architecture)
IBM 1974 by the first computer network architectureIBMrsquos SNA is a proprietary architectureNOTENot SNA(storage area network) Most network architectures developed since use a layered approach
Chapter 3 Network Architetures and Standarts
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Communication standardThe rules that are established to ensure compatibility among similar communications products and servicesCommunications standards are the flesh on the architectural skeletonThey specify how a particular communications product serviceor interface will operate
V90 modem
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33 why have network architectures
1Communication system were becoming too complex2 wanted to be isolated from the complexities of the network3Wanted to connect different types of devices to the network4Distributed processing and client-server processing became practical5Network needed to be managed
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BackgroundCommunications vendors realized early standardscomputer manufacturers were slower to recognize the need for standardsCustomers demanded that product was standardization
34 TWO VIEWPOINTS ABOUT STANDARDS
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People who have a strong networking background see the computer as a tool to enhance a network`s capability
One
Tend to wait for standards and follow them closely
Chapter 3 Network Architetures and Standarts
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Figure 3-1 Two different views of the relative roles of networks and computers
Those who have a strong computer background tend to focus on what can be done with software or specially designed circuit chips for computers
They forge ahead of the standards-making process
Two
Chapter 3 Network Architetures and Standarts
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Purport While neither viewpoint is wrong it leads to differing philosophiesBoth are legitimate and have their place
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35 STANDS AND STANDS-MAKING ORGANIZATIONS Because of the recognized need for common international standards there is a great deal of cooperation among communications standards making organizations Data communication standards are more complicated than Voice communication standardsEarly standards were mostly electrical in nature The standards-setting process is slowWriting standards is difficult work
Chapter 3 Network Architetures and Standarts
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ITU (The International Telecommunication Union)
1865 in the U S was established in Paris 1947 as part of the United Nations members from 188 countries headquartered in Geneva SwitzerlandThe most important telecommunications standards-setting organization in the world is the ITU ITU-T has created two sets of standards for the electrical connection of terminals to communications networks
Chapter 3 Network Architetures and Standarts
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ISOInternational Standards OrganizationDonrsquot confuse the OSI with ISO and IOSISO means the international organization for standardizationIOS (internet operation system) is used in CISCO systemrsquos routers and switches
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Figure of the organizations involved in setting telecommunications standards or in passing input to the standards-setting bodies
The American National Standards Institute (ANSI) is not involved in setting communications standards The official TCPIP model is now maintained by the IETFAll communications standards are developed by one organization the ISOF
Chapter 3 Network Architetures and Standarts
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36 V STANDARD XSTANDARD
The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called the V and X standards
Chapter 3 Network Architetures and Standarts
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Vstandards define the connection of digital equipment to the PSTN`s analog linesV32 V33 V42 standard for the use of telephone transmission of data made a clear statement XstandardsDefine the connection of digital equipment to digital linesEG X25 X400 X500
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37 ADVANTAGES AND DISADVANTAGES OF STANDARDS
Adv Standards allow products from multiple vendors to be connected to one another and to communicate
Chapter 3 Network Architetures and Standarts
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disadvanceThe standards-setting process is slowStandards tend to freeze technologyMultiple conflicting standardsThe standards-setting process can occur quickly(Writing standards is relatively easy ) when an architecture is in placeF
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38 COMMUNICATIONS ARCHITECTURESISO and ITU-T developed OSI reference model in 1978OSI-RM Open Systems Interconnection reference modelThe standards development process took so long that the osi model never came into widespread useIt is the standard reference point by which data communications networks are described
Chapter 3 Network Architetures and Standarts
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39 THE ISO`S OSI REFERENCE MODEL391 Objective Provide a basis for interconnecting dissimilar systems for the purpose of information exchange Define communications rules
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OSI and most network architecture use a layered approach A layer in the OSI RM represents a component of the total process of communicating Each one layer requests services from the layer below it N layer Provide services to N+1 layer The same network any two-system must have the same level The actual physical communication completed only in the bottom layer
Chapter 3 Network Architetures and Standarts
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1) Layering forces the modularization of function Dealing with complex systemsThe output of laying definition process is standardseases maintenance updating of systemOne layer can be changed without affecting other layersDifferent implementations can be substituted relativelyTransparently
Why layering
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layer Layer requires reasonably sophisticated software and hardware at each end of the connection
前置处理机CCP
中央主机 中央主机中央主机
前置处理机
前置处理机
Chapter 3 Network Architetures and Standarts
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The philosopher-translator-Secretary architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
CN scientists
CN Translate
CNTelegrafisten
Telex machine
JP scientists
JP Translate
JPTelegrafisten
Telex machine
protocol
protocol
protocol
protocol
Scientific opinion
English
Letters
Telegraph code
Example Scientific exchange layered
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Architecture Layered principle Basic concept
Entity Can send or receive any information of hardware software process Peer layer Two different systems the same level Interface Interaction between the two neighboring layerSERVE for the upper classes a capacity to provide services through the interface Protocol Communication both in communication must comply with the rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
SYSA
SYSBentity Pee
r layerpeer
entity
server
Physical communication line
Layered network Architecture SYS
B
P3P2P1
2 1
3 2 1
Physical communication line
3
N+1 N N-1
N+1 N N-1Pn-1
Pn
Pn+1
SYSA
interfact
The way that the interaction between the layers actually takes place is that each one requests services from the layer above it
Chapter 3 Network Architetures and Standarts
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Services The way that the interaction between the layers actually takes place is that each one requests services from the layer above itEach layer provides services to the next higher layer
Chapter 3 Network Architetures and Standarts
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Service PrimitivesPrimitiv
eMeaning
Request An Entity wants the service to do some work
Indication
An Entity is to be informed about an event
Response
An Entity wants to respond to an event
Confirm The Response to an eariler request has come back
Chapter 3 Network Architetures and Standarts
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服务用户( N+1 )
服务提供者( N )系统 A 服务用户
( N+1 )服务提供者
( N )系统 B
无需证实Request
Indication
RequestIndication
Response
Confirm
需证实PDU
Relations among Service Primitives
Chapter 3 Network Architetures and Standarts
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电话系统工作示例例如张三打电话请李四吃饭服务提供者为电话局 ① CONNECT request 张三拨李四的电话号码 ② CONNECT i ndi cati on 李四的电话振铃 ③ CONNECT response 李四摘机 ④ CONNECT confi rm 张三听到振铃停止知道有人应答 ⑤ DATA request 张三说话发出邀请 ⑥ DATA i ndi cati on 李四听到张三的邀请 ⑦ DATA request 李四说话接受邀请 ⑧ DATA i ndi cati on 张三听到李四的答复 ⑨ DI SCONNECT request 李四挂机 ⑩ DI SCONNECT i ndi cat i on 张三听到李四挂机也挂机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Protocols can provide a service for upper layer
Protocols is ldquolevelrdquo But Services is ldquoVertical rdquo Service is adopted by the lower layer of
interface Functions is the internal activities
Services interface protocols and functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services to Protocols Relationship
The relationship between a service and a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layers of the ISOrsquos OSI reference model The layers of the OSI model on each node
communicate with each other
A layer in the OSI model represents a compon-ent of the total process of communicating T
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Actual communication passes down through the layers on the sending node and then up through the layers on the receiving node
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
X25The first three layers of the OSI model have been standardized and together are called the X25 standard for data transmission
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
GOSIP government open system Interconnetion Protocola subset of the OSI model that vendors must support if they want to sell network services or equipment to the US governmentGOSIP is neither a new architecture nor a New standardIt is a more precise specification of what parts of the OSI model the government will use
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipment
What are the Physical Layer components on my computer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
Chapter 3 Network Architetures and Standarts
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Chapter 3 Network Architetures and Standarts
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LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
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Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
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Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
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Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
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Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
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Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
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Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
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Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
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TCPIP and the OSI Model
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Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
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UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
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Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
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Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
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Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
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Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
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IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
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OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
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The ATM reference model
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NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
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Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
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A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
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Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
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3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
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OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
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Network Management and Operation wwwgxmueducn
Single Layer Model First Communication Between Computer DevicesThe communication and application software be intermingled (To mix)
DEVICE A
Hardwareamp
Software
Hardwareamp
Software
DEVICE B1
The early networks were not flexibleSingle specification for all aspects of communication
Chapter 3 Network Architetures and Standarts
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IBM SNA(System Network Architecture)
IBM 1974 by the first computer network architectureIBMrsquos SNA is a proprietary architectureNOTENot SNA(storage area network) Most network architectures developed since use a layered approach
Chapter 3 Network Architetures and Standarts
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Communication standardThe rules that are established to ensure compatibility among similar communications products and servicesCommunications standards are the flesh on the architectural skeletonThey specify how a particular communications product serviceor interface will operate
V90 modem
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33 why have network architectures
1Communication system were becoming too complex2 wanted to be isolated from the complexities of the network3Wanted to connect different types of devices to the network4Distributed processing and client-server processing became practical5Network needed to be managed
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BackgroundCommunications vendors realized early standardscomputer manufacturers were slower to recognize the need for standardsCustomers demanded that product was standardization
34 TWO VIEWPOINTS ABOUT STANDARDS
Chapter 3 Network Architetures and Standarts
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People who have a strong networking background see the computer as a tool to enhance a network`s capability
One
Tend to wait for standards and follow them closely
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Network Management and Operation wwwgxmueducn
Figure 3-1 Two different views of the relative roles of networks and computers
Those who have a strong computer background tend to focus on what can be done with software or specially designed circuit chips for computers
They forge ahead of the standards-making process
Two
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Purport While neither viewpoint is wrong it leads to differing philosophiesBoth are legitimate and have their place
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35 STANDS AND STANDS-MAKING ORGANIZATIONS Because of the recognized need for common international standards there is a great deal of cooperation among communications standards making organizations Data communication standards are more complicated than Voice communication standardsEarly standards were mostly electrical in nature The standards-setting process is slowWriting standards is difficult work
Chapter 3 Network Architetures and Standarts
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ITU (The International Telecommunication Union)
1865 in the U S was established in Paris 1947 as part of the United Nations members from 188 countries headquartered in Geneva SwitzerlandThe most important telecommunications standards-setting organization in the world is the ITU ITU-T has created two sets of standards for the electrical connection of terminals to communications networks
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
ISOInternational Standards OrganizationDonrsquot confuse the OSI with ISO and IOSISO means the international organization for standardizationIOS (internet operation system) is used in CISCO systemrsquos routers and switches
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Figure of the organizations involved in setting telecommunications standards or in passing input to the standards-setting bodies
The American National Standards Institute (ANSI) is not involved in setting communications standards The official TCPIP model is now maintained by the IETFAll communications standards are developed by one organization the ISOF
Chapter 3 Network Architetures and Standarts
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36 V STANDARD XSTANDARD
The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called the V and X standards
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Vstandards define the connection of digital equipment to the PSTN`s analog linesV32 V33 V42 standard for the use of telephone transmission of data made a clear statement XstandardsDefine the connection of digital equipment to digital linesEG X25 X400 X500
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37 ADVANTAGES AND DISADVANTAGES OF STANDARDS
Adv Standards allow products from multiple vendors to be connected to one another and to communicate
Chapter 3 Network Architetures and Standarts
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disadvanceThe standards-setting process is slowStandards tend to freeze technologyMultiple conflicting standardsThe standards-setting process can occur quickly(Writing standards is relatively easy ) when an architecture is in placeF
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38 COMMUNICATIONS ARCHITECTURESISO and ITU-T developed OSI reference model in 1978OSI-RM Open Systems Interconnection reference modelThe standards development process took so long that the osi model never came into widespread useIt is the standard reference point by which data communications networks are described
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39 THE ISO`S OSI REFERENCE MODEL391 Objective Provide a basis for interconnecting dissimilar systems for the purpose of information exchange Define communications rules
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OSI and most network architecture use a layered approach A layer in the OSI RM represents a component of the total process of communicating Each one layer requests services from the layer below it N layer Provide services to N+1 layer The same network any two-system must have the same level The actual physical communication completed only in the bottom layer
Chapter 3 Network Architetures and Standarts
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1) Layering forces the modularization of function Dealing with complex systemsThe output of laying definition process is standardseases maintenance updating of systemOne layer can be changed without affecting other layersDifferent implementations can be substituted relativelyTransparently
Why layering
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Network Management and Operation wwwgxmueducn
Layer Layer requires reasonably sophisticated software and hardware at each end of the connection
前置处理机CCP
中央主机 中央主机中央主机
前置处理机
前置处理机
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The philosopher-translator-Secretary architecture
Chapter 3 Network Architetures and Standarts
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CN scientists
CN Translate
CNTelegrafisten
Telex machine
JP scientists
JP Translate
JPTelegrafisten
Telex machine
protocol
protocol
protocol
protocol
Scientific opinion
English
Letters
Telegraph code
Example Scientific exchange layered
Chapter 3 Network Architetures and Standarts
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Network Architecture Layered principle Basic concept
Entity Can send or receive any information of hardware software process Peer layer Two different systems the same level Interface Interaction between the two neighboring layerSERVE for the upper classes a capacity to provide services through the interface Protocol Communication both in communication must comply with the rules
Chapter 3 Network Architetures and Standarts
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SYSA
SYSBentity Pee
r layerpeer
entity
server
Physical communication line
Layered network Architecture SYS
B
P3P2P1
2 1
3 2 1
Physical communication line
3
N+1 N N-1
N+1 N N-1Pn-1
Pn
Pn+1
SYSA
interfact
The way that the interaction between the layers actually takes place is that each one requests services from the layer above it
Chapter 3 Network Architetures and Standarts
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Services The way that the interaction between the layers actually takes place is that each one requests services from the layer above itEach layer provides services to the next higher layer
Chapter 3 Network Architetures and Standarts
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Service PrimitivesPrimitiv
eMeaning
Request An Entity wants the service to do some work
Indication
An Entity is to be informed about an event
Response
An Entity wants to respond to an event
Confirm The Response to an eariler request has come back
Chapter 3 Network Architetures and Standarts
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服务用户( N+1 )
服务提供者( N )系统 A 服务用户
( N+1 )服务提供者
( N )系统 B
无需证实Request
Indication
RequestIndication
Response
Confirm
需证实PDU
Relations among Service Primitives
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
电话系统工作示例例如张三打电话请李四吃饭服务提供者为电话局 ① CONNECT request 张三拨李四的电话号码 ② CONNECT i ndi cati on 李四的电话振铃 ③ CONNECT response 李四摘机 ④ CONNECT confi rm 张三听到振铃停止知道有人应答 ⑤ DATA request 张三说话发出邀请 ⑥ DATA i ndi cati on 李四听到张三的邀请 ⑦ DATA request 李四说话接受邀请 ⑧ DATA i ndi cati on 张三听到李四的答复 ⑨ DI SCONNECT request 李四挂机 ⑩ DI SCONNECT i ndi cat i on 张三听到李四挂机也挂机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Protocols can provide a service for upper layer
Protocols is ldquolevelrdquo But Services is ldquoVertical rdquo Service is adopted by the lower layer of
interface Functions is the internal activities
Services interface protocols and functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services to Protocols Relationship
The relationship between a service and a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layers of the ISOrsquos OSI reference model The layers of the OSI model on each node
communicate with each other
A layer in the OSI model represents a compon-ent of the total process of communicating T
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Actual communication passes down through the layers on the sending node and then up through the layers on the receiving node
Chapter 3 Network Architetures and Standarts
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X25The first three layers of the OSI model have been standardized and together are called the X25 standard for data transmission
Chapter 3 Network Architetures and Standarts
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GOSIP government open system Interconnetion Protocola subset of the OSI model that vendors must support if they want to sell network services or equipment to the US governmentGOSIP is neither a new architecture nor a New standardIt is a more precise specification of what parts of the OSI model the government will use
Chapter 3 Network Architetures and Standarts
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392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
Chapter 3 Network Architetures and Standarts
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Typical equipment
What are the Physical Layer components on my computer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
Chapter 3 Network Architetures and Standarts
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LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
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Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
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Chapter 3 Network Architetures and Standarts
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Network Interface Card Bridge
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LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
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LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
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Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
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Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
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Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
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Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
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310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
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Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
IBM SNA(System Network Architecture)
IBM 1974 by the first computer network architectureIBMrsquos SNA is a proprietary architectureNOTENot SNA(storage area network) Most network architectures developed since use a layered approach
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Communication standardThe rules that are established to ensure compatibility among similar communications products and servicesCommunications standards are the flesh on the architectural skeletonThey specify how a particular communications product serviceor interface will operate
V90 modem
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
33 why have network architectures
1Communication system were becoming too complex2 wanted to be isolated from the complexities of the network3Wanted to connect different types of devices to the network4Distributed processing and client-server processing became practical5Network needed to be managed
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
BackgroundCommunications vendors realized early standardscomputer manufacturers were slower to recognize the need for standardsCustomers demanded that product was standardization
34 TWO VIEWPOINTS ABOUT STANDARDS
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
People who have a strong networking background see the computer as a tool to enhance a network`s capability
One
Tend to wait for standards and follow them closely
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Figure 3-1 Two different views of the relative roles of networks and computers
Those who have a strong computer background tend to focus on what can be done with software or specially designed circuit chips for computers
They forge ahead of the standards-making process
Two
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Purport While neither viewpoint is wrong it leads to differing philosophiesBoth are legitimate and have their place
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Network Management and Operation wwwgxmueducn
35 STANDS AND STANDS-MAKING ORGANIZATIONS Because of the recognized need for common international standards there is a great deal of cooperation among communications standards making organizations Data communication standards are more complicated than Voice communication standardsEarly standards were mostly electrical in nature The standards-setting process is slowWriting standards is difficult work
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
ITU (The International Telecommunication Union)
1865 in the U S was established in Paris 1947 as part of the United Nations members from 188 countries headquartered in Geneva SwitzerlandThe most important telecommunications standards-setting organization in the world is the ITU ITU-T has created two sets of standards for the electrical connection of terminals to communications networks
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
ISOInternational Standards OrganizationDonrsquot confuse the OSI with ISO and IOSISO means the international organization for standardizationIOS (internet operation system) is used in CISCO systemrsquos routers and switches
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Figure of the organizations involved in setting telecommunications standards or in passing input to the standards-setting bodies
The American National Standards Institute (ANSI) is not involved in setting communications standards The official TCPIP model is now maintained by the IETFAll communications standards are developed by one organization the ISOF
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
36 V STANDARD XSTANDARD
The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called the V and X standards
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Vstandards define the connection of digital equipment to the PSTN`s analog linesV32 V33 V42 standard for the use of telephone transmission of data made a clear statement XstandardsDefine the connection of digital equipment to digital linesEG X25 X400 X500
Chapter 3 Network Architetures and Standarts
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37 ADVANTAGES AND DISADVANTAGES OF STANDARDS
Adv Standards allow products from multiple vendors to be connected to one another and to communicate
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
disadvanceThe standards-setting process is slowStandards tend to freeze technologyMultiple conflicting standardsThe standards-setting process can occur quickly(Writing standards is relatively easy ) when an architecture is in placeF
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
38 COMMUNICATIONS ARCHITECTURESISO and ITU-T developed OSI reference model in 1978OSI-RM Open Systems Interconnection reference modelThe standards development process took so long that the osi model never came into widespread useIt is the standard reference point by which data communications networks are described
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
39 THE ISO`S OSI REFERENCE MODEL391 Objective Provide a basis for interconnecting dissimilar systems for the purpose of information exchange Define communications rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI and most network architecture use a layered approach A layer in the OSI RM represents a component of the total process of communicating Each one layer requests services from the layer below it N layer Provide services to N+1 layer The same network any two-system must have the same level The actual physical communication completed only in the bottom layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
1) Layering forces the modularization of function Dealing with complex systemsThe output of laying definition process is standardseases maintenance updating of systemOne layer can be changed without affecting other layersDifferent implementations can be substituted relativelyTransparently
Why layering
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layer Layer requires reasonably sophisticated software and hardware at each end of the connection
前置处理机CCP
中央主机 中央主机中央主机
前置处理机
前置处理机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The philosopher-translator-Secretary architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
CN scientists
CN Translate
CNTelegrafisten
Telex machine
JP scientists
JP Translate
JPTelegrafisten
Telex machine
protocol
protocol
protocol
protocol
Scientific opinion
English
Letters
Telegraph code
Example Scientific exchange layered
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Architecture Layered principle Basic concept
Entity Can send or receive any information of hardware software process Peer layer Two different systems the same level Interface Interaction between the two neighboring layerSERVE for the upper classes a capacity to provide services through the interface Protocol Communication both in communication must comply with the rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
SYSA
SYSBentity Pee
r layerpeer
entity
server
Physical communication line
Layered network Architecture SYS
B
P3P2P1
2 1
3 2 1
Physical communication line
3
N+1 N N-1
N+1 N N-1Pn-1
Pn
Pn+1
SYSA
interfact
The way that the interaction between the layers actually takes place is that each one requests services from the layer above it
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services The way that the interaction between the layers actually takes place is that each one requests services from the layer above itEach layer provides services to the next higher layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Service PrimitivesPrimitiv
eMeaning
Request An Entity wants the service to do some work
Indication
An Entity is to be informed about an event
Response
An Entity wants to respond to an event
Confirm The Response to an eariler request has come back
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
服务用户( N+1 )
服务提供者( N )系统 A 服务用户
( N+1 )服务提供者
( N )系统 B
无需证实Request
Indication
RequestIndication
Response
Confirm
需证实PDU
Relations among Service Primitives
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
电话系统工作示例例如张三打电话请李四吃饭服务提供者为电话局 ① CONNECT request 张三拨李四的电话号码 ② CONNECT i ndi cati on 李四的电话振铃 ③ CONNECT response 李四摘机 ④ CONNECT confi rm 张三听到振铃停止知道有人应答 ⑤ DATA request 张三说话发出邀请 ⑥ DATA i ndi cati on 李四听到张三的邀请 ⑦ DATA request 李四说话接受邀请 ⑧ DATA i ndi cati on 张三听到李四的答复 ⑨ DI SCONNECT request 李四挂机 ⑩ DI SCONNECT i ndi cat i on 张三听到李四挂机也挂机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Protocols can provide a service for upper layer
Protocols is ldquolevelrdquo But Services is ldquoVertical rdquo Service is adopted by the lower layer of
interface Functions is the internal activities
Services interface protocols and functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services to Protocols Relationship
The relationship between a service and a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layers of the ISOrsquos OSI reference model The layers of the OSI model on each node
communicate with each other
A layer in the OSI model represents a compon-ent of the total process of communicating T
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Actual communication passes down through the layers on the sending node and then up through the layers on the receiving node
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
X25The first three layers of the OSI model have been standardized and together are called the X25 standard for data transmission
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
GOSIP government open system Interconnetion Protocola subset of the OSI model that vendors must support if they want to sell network services or equipment to the US governmentGOSIP is neither a new architecture nor a New standardIt is a more precise specification of what parts of the OSI model the government will use
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipment
What are the Physical Layer components on my computer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
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LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
Chapter 3 Network Architetures and Standarts
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Chapter 3 Network Architetures and Standarts
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Network Interface Card Bridge
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LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
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Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
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LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
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Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
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Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
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Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
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OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
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Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
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Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
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OSI 模型是协助网络检修人员识别网络问题一种理想的框架
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310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
Communication standardThe rules that are established to ensure compatibility among similar communications products and servicesCommunications standards are the flesh on the architectural skeletonThey specify how a particular communications product serviceor interface will operate
V90 modem
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
33 why have network architectures
1Communication system were becoming too complex2 wanted to be isolated from the complexities of the network3Wanted to connect different types of devices to the network4Distributed processing and client-server processing became practical5Network needed to be managed
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
BackgroundCommunications vendors realized early standardscomputer manufacturers were slower to recognize the need for standardsCustomers demanded that product was standardization
34 TWO VIEWPOINTS ABOUT STANDARDS
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
People who have a strong networking background see the computer as a tool to enhance a network`s capability
One
Tend to wait for standards and follow them closely
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Figure 3-1 Two different views of the relative roles of networks and computers
Those who have a strong computer background tend to focus on what can be done with software or specially designed circuit chips for computers
They forge ahead of the standards-making process
Two
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Purport While neither viewpoint is wrong it leads to differing philosophiesBoth are legitimate and have their place
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
35 STANDS AND STANDS-MAKING ORGANIZATIONS Because of the recognized need for common international standards there is a great deal of cooperation among communications standards making organizations Data communication standards are more complicated than Voice communication standardsEarly standards were mostly electrical in nature The standards-setting process is slowWriting standards is difficult work
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
ITU (The International Telecommunication Union)
1865 in the U S was established in Paris 1947 as part of the United Nations members from 188 countries headquartered in Geneva SwitzerlandThe most important telecommunications standards-setting organization in the world is the ITU ITU-T has created two sets of standards for the electrical connection of terminals to communications networks
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
ISOInternational Standards OrganizationDonrsquot confuse the OSI with ISO and IOSISO means the international organization for standardizationIOS (internet operation system) is used in CISCO systemrsquos routers and switches
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Figure of the organizations involved in setting telecommunications standards or in passing input to the standards-setting bodies
The American National Standards Institute (ANSI) is not involved in setting communications standards The official TCPIP model is now maintained by the IETFAll communications standards are developed by one organization the ISOF
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
36 V STANDARD XSTANDARD
The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called the V and X standards
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Vstandards define the connection of digital equipment to the PSTN`s analog linesV32 V33 V42 standard for the use of telephone transmission of data made a clear statement XstandardsDefine the connection of digital equipment to digital linesEG X25 X400 X500
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
37 ADVANTAGES AND DISADVANTAGES OF STANDARDS
Adv Standards allow products from multiple vendors to be connected to one another and to communicate
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
disadvanceThe standards-setting process is slowStandards tend to freeze technologyMultiple conflicting standardsThe standards-setting process can occur quickly(Writing standards is relatively easy ) when an architecture is in placeF
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
38 COMMUNICATIONS ARCHITECTURESISO and ITU-T developed OSI reference model in 1978OSI-RM Open Systems Interconnection reference modelThe standards development process took so long that the osi model never came into widespread useIt is the standard reference point by which data communications networks are described
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
39 THE ISO`S OSI REFERENCE MODEL391 Objective Provide a basis for interconnecting dissimilar systems for the purpose of information exchange Define communications rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI and most network architecture use a layered approach A layer in the OSI RM represents a component of the total process of communicating Each one layer requests services from the layer below it N layer Provide services to N+1 layer The same network any two-system must have the same level The actual physical communication completed only in the bottom layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
1) Layering forces the modularization of function Dealing with complex systemsThe output of laying definition process is standardseases maintenance updating of systemOne layer can be changed without affecting other layersDifferent implementations can be substituted relativelyTransparently
Why layering
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layer Layer requires reasonably sophisticated software and hardware at each end of the connection
前置处理机CCP
中央主机 中央主机中央主机
前置处理机
前置处理机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The philosopher-translator-Secretary architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
CN scientists
CN Translate
CNTelegrafisten
Telex machine
JP scientists
JP Translate
JPTelegrafisten
Telex machine
protocol
protocol
protocol
protocol
Scientific opinion
English
Letters
Telegraph code
Example Scientific exchange layered
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Architecture Layered principle Basic concept
Entity Can send or receive any information of hardware software process Peer layer Two different systems the same level Interface Interaction between the two neighboring layerSERVE for the upper classes a capacity to provide services through the interface Protocol Communication both in communication must comply with the rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
SYSA
SYSBentity Pee
r layerpeer
entity
server
Physical communication line
Layered network Architecture SYS
B
P3P2P1
2 1
3 2 1
Physical communication line
3
N+1 N N-1
N+1 N N-1Pn-1
Pn
Pn+1
SYSA
interfact
The way that the interaction between the layers actually takes place is that each one requests services from the layer above it
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services The way that the interaction between the layers actually takes place is that each one requests services from the layer above itEach layer provides services to the next higher layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Service PrimitivesPrimitiv
eMeaning
Request An Entity wants the service to do some work
Indication
An Entity is to be informed about an event
Response
An Entity wants to respond to an event
Confirm The Response to an eariler request has come back
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
服务用户( N+1 )
服务提供者( N )系统 A 服务用户
( N+1 )服务提供者
( N )系统 B
无需证实Request
Indication
RequestIndication
Response
Confirm
需证实PDU
Relations among Service Primitives
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
电话系统工作示例例如张三打电话请李四吃饭服务提供者为电话局 ① CONNECT request 张三拨李四的电话号码 ② CONNECT i ndi cati on 李四的电话振铃 ③ CONNECT response 李四摘机 ④ CONNECT confi rm 张三听到振铃停止知道有人应答 ⑤ DATA request 张三说话发出邀请 ⑥ DATA i ndi cati on 李四听到张三的邀请 ⑦ DATA request 李四说话接受邀请 ⑧ DATA i ndi cati on 张三听到李四的答复 ⑨ DI SCONNECT request 李四挂机 ⑩ DI SCONNECT i ndi cat i on 张三听到李四挂机也挂机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Protocols can provide a service for upper layer
Protocols is ldquolevelrdquo But Services is ldquoVertical rdquo Service is adopted by the lower layer of
interface Functions is the internal activities
Services interface protocols and functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services to Protocols Relationship
The relationship between a service and a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layers of the ISOrsquos OSI reference model The layers of the OSI model on each node
communicate with each other
A layer in the OSI model represents a compon-ent of the total process of communicating T
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Actual communication passes down through the layers on the sending node and then up through the layers on the receiving node
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
X25The first three layers of the OSI model have been standardized and together are called the X25 standard for data transmission
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
GOSIP government open system Interconnetion Protocola subset of the OSI model that vendors must support if they want to sell network services or equipment to the US governmentGOSIP is neither a new architecture nor a New standardIt is a more precise specification of what parts of the OSI model the government will use
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipment
What are the Physical Layer components on my computer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
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Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
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Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
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310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
33 why have network architectures
1Communication system were becoming too complex2 wanted to be isolated from the complexities of the network3Wanted to connect different types of devices to the network4Distributed processing and client-server processing became practical5Network needed to be managed
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
BackgroundCommunications vendors realized early standardscomputer manufacturers were slower to recognize the need for standardsCustomers demanded that product was standardization
34 TWO VIEWPOINTS ABOUT STANDARDS
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
People who have a strong networking background see the computer as a tool to enhance a network`s capability
One
Tend to wait for standards and follow them closely
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Figure 3-1 Two different views of the relative roles of networks and computers
Those who have a strong computer background tend to focus on what can be done with software or specially designed circuit chips for computers
They forge ahead of the standards-making process
Two
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Purport While neither viewpoint is wrong it leads to differing philosophiesBoth are legitimate and have their place
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
35 STANDS AND STANDS-MAKING ORGANIZATIONS Because of the recognized need for common international standards there is a great deal of cooperation among communications standards making organizations Data communication standards are more complicated than Voice communication standardsEarly standards were mostly electrical in nature The standards-setting process is slowWriting standards is difficult work
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
ITU (The International Telecommunication Union)
1865 in the U S was established in Paris 1947 as part of the United Nations members from 188 countries headquartered in Geneva SwitzerlandThe most important telecommunications standards-setting organization in the world is the ITU ITU-T has created two sets of standards for the electrical connection of terminals to communications networks
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
ISOInternational Standards OrganizationDonrsquot confuse the OSI with ISO and IOSISO means the international organization for standardizationIOS (internet operation system) is used in CISCO systemrsquos routers and switches
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Figure of the organizations involved in setting telecommunications standards or in passing input to the standards-setting bodies
The American National Standards Institute (ANSI) is not involved in setting communications standards The official TCPIP model is now maintained by the IETFAll communications standards are developed by one organization the ISOF
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
36 V STANDARD XSTANDARD
The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called the V and X standards
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Vstandards define the connection of digital equipment to the PSTN`s analog linesV32 V33 V42 standard for the use of telephone transmission of data made a clear statement XstandardsDefine the connection of digital equipment to digital linesEG X25 X400 X500
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
37 ADVANTAGES AND DISADVANTAGES OF STANDARDS
Adv Standards allow products from multiple vendors to be connected to one another and to communicate
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
disadvanceThe standards-setting process is slowStandards tend to freeze technologyMultiple conflicting standardsThe standards-setting process can occur quickly(Writing standards is relatively easy ) when an architecture is in placeF
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
38 COMMUNICATIONS ARCHITECTURESISO and ITU-T developed OSI reference model in 1978OSI-RM Open Systems Interconnection reference modelThe standards development process took so long that the osi model never came into widespread useIt is the standard reference point by which data communications networks are described
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
39 THE ISO`S OSI REFERENCE MODEL391 Objective Provide a basis for interconnecting dissimilar systems for the purpose of information exchange Define communications rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI and most network architecture use a layered approach A layer in the OSI RM represents a component of the total process of communicating Each one layer requests services from the layer below it N layer Provide services to N+1 layer The same network any two-system must have the same level The actual physical communication completed only in the bottom layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
1) Layering forces the modularization of function Dealing with complex systemsThe output of laying definition process is standardseases maintenance updating of systemOne layer can be changed without affecting other layersDifferent implementations can be substituted relativelyTransparently
Why layering
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layer Layer requires reasonably sophisticated software and hardware at each end of the connection
前置处理机CCP
中央主机 中央主机中央主机
前置处理机
前置处理机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The philosopher-translator-Secretary architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
CN scientists
CN Translate
CNTelegrafisten
Telex machine
JP scientists
JP Translate
JPTelegrafisten
Telex machine
protocol
protocol
protocol
protocol
Scientific opinion
English
Letters
Telegraph code
Example Scientific exchange layered
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Architecture Layered principle Basic concept
Entity Can send or receive any information of hardware software process Peer layer Two different systems the same level Interface Interaction between the two neighboring layerSERVE for the upper classes a capacity to provide services through the interface Protocol Communication both in communication must comply with the rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
SYSA
SYSBentity Pee
r layerpeer
entity
server
Physical communication line
Layered network Architecture SYS
B
P3P2P1
2 1
3 2 1
Physical communication line
3
N+1 N N-1
N+1 N N-1Pn-1
Pn
Pn+1
SYSA
interfact
The way that the interaction between the layers actually takes place is that each one requests services from the layer above it
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services The way that the interaction between the layers actually takes place is that each one requests services from the layer above itEach layer provides services to the next higher layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Service PrimitivesPrimitiv
eMeaning
Request An Entity wants the service to do some work
Indication
An Entity is to be informed about an event
Response
An Entity wants to respond to an event
Confirm The Response to an eariler request has come back
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
服务用户( N+1 )
服务提供者( N )系统 A 服务用户
( N+1 )服务提供者
( N )系统 B
无需证实Request
Indication
RequestIndication
Response
Confirm
需证实PDU
Relations among Service Primitives
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
电话系统工作示例例如张三打电话请李四吃饭服务提供者为电话局 ① CONNECT request 张三拨李四的电话号码 ② CONNECT i ndi cati on 李四的电话振铃 ③ CONNECT response 李四摘机 ④ CONNECT confi rm 张三听到振铃停止知道有人应答 ⑤ DATA request 张三说话发出邀请 ⑥ DATA i ndi cati on 李四听到张三的邀请 ⑦ DATA request 李四说话接受邀请 ⑧ DATA i ndi cati on 张三听到李四的答复 ⑨ DI SCONNECT request 李四挂机 ⑩ DI SCONNECT i ndi cat i on 张三听到李四挂机也挂机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Protocols can provide a service for upper layer
Protocols is ldquolevelrdquo But Services is ldquoVertical rdquo Service is adopted by the lower layer of
interface Functions is the internal activities
Services interface protocols and functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services to Protocols Relationship
The relationship between a service and a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layers of the ISOrsquos OSI reference model The layers of the OSI model on each node
communicate with each other
A layer in the OSI model represents a compon-ent of the total process of communicating T
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Actual communication passes down through the layers on the sending node and then up through the layers on the receiving node
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
X25The first three layers of the OSI model have been standardized and together are called the X25 standard for data transmission
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
GOSIP government open system Interconnetion Protocola subset of the OSI model that vendors must support if they want to sell network services or equipment to the US governmentGOSIP is neither a new architecture nor a New standardIt is a more precise specification of what parts of the OSI model the government will use
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipment
What are the Physical Layer components on my computer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
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310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
BackgroundCommunications vendors realized early standardscomputer manufacturers were slower to recognize the need for standardsCustomers demanded that product was standardization
34 TWO VIEWPOINTS ABOUT STANDARDS
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Network Management and Operation wwwgxmueducn
People who have a strong networking background see the computer as a tool to enhance a network`s capability
One
Tend to wait for standards and follow them closely
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Figure 3-1 Two different views of the relative roles of networks and computers
Those who have a strong computer background tend to focus on what can be done with software or specially designed circuit chips for computers
They forge ahead of the standards-making process
Two
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Purport While neither viewpoint is wrong it leads to differing philosophiesBoth are legitimate and have their place
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
35 STANDS AND STANDS-MAKING ORGANIZATIONS Because of the recognized need for common international standards there is a great deal of cooperation among communications standards making organizations Data communication standards are more complicated than Voice communication standardsEarly standards were mostly electrical in nature The standards-setting process is slowWriting standards is difficult work
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
ITU (The International Telecommunication Union)
1865 in the U S was established in Paris 1947 as part of the United Nations members from 188 countries headquartered in Geneva SwitzerlandThe most important telecommunications standards-setting organization in the world is the ITU ITU-T has created two sets of standards for the electrical connection of terminals to communications networks
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
ISOInternational Standards OrganizationDonrsquot confuse the OSI with ISO and IOSISO means the international organization for standardizationIOS (internet operation system) is used in CISCO systemrsquos routers and switches
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Figure of the organizations involved in setting telecommunications standards or in passing input to the standards-setting bodies
The American National Standards Institute (ANSI) is not involved in setting communications standards The official TCPIP model is now maintained by the IETFAll communications standards are developed by one organization the ISOF
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
36 V STANDARD XSTANDARD
The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called the V and X standards
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Vstandards define the connection of digital equipment to the PSTN`s analog linesV32 V33 V42 standard for the use of telephone transmission of data made a clear statement XstandardsDefine the connection of digital equipment to digital linesEG X25 X400 X500
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
37 ADVANTAGES AND DISADVANTAGES OF STANDARDS
Adv Standards allow products from multiple vendors to be connected to one another and to communicate
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
disadvanceThe standards-setting process is slowStandards tend to freeze technologyMultiple conflicting standardsThe standards-setting process can occur quickly(Writing standards is relatively easy ) when an architecture is in placeF
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
38 COMMUNICATIONS ARCHITECTURESISO and ITU-T developed OSI reference model in 1978OSI-RM Open Systems Interconnection reference modelThe standards development process took so long that the osi model never came into widespread useIt is the standard reference point by which data communications networks are described
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
39 THE ISO`S OSI REFERENCE MODEL391 Objective Provide a basis for interconnecting dissimilar systems for the purpose of information exchange Define communications rules
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Network Management and Operation wwwgxmueducn
OSI and most network architecture use a layered approach A layer in the OSI RM represents a component of the total process of communicating Each one layer requests services from the layer below it N layer Provide services to N+1 layer The same network any two-system must have the same level The actual physical communication completed only in the bottom layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
1) Layering forces the modularization of function Dealing with complex systemsThe output of laying definition process is standardseases maintenance updating of systemOne layer can be changed without affecting other layersDifferent implementations can be substituted relativelyTransparently
Why layering
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layer Layer requires reasonably sophisticated software and hardware at each end of the connection
前置处理机CCP
中央主机 中央主机中央主机
前置处理机
前置处理机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The philosopher-translator-Secretary architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
CN scientists
CN Translate
CNTelegrafisten
Telex machine
JP scientists
JP Translate
JPTelegrafisten
Telex machine
protocol
protocol
protocol
protocol
Scientific opinion
English
Letters
Telegraph code
Example Scientific exchange layered
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Architecture Layered principle Basic concept
Entity Can send or receive any information of hardware software process Peer layer Two different systems the same level Interface Interaction between the two neighboring layerSERVE for the upper classes a capacity to provide services through the interface Protocol Communication both in communication must comply with the rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
SYSA
SYSBentity Pee
r layerpeer
entity
server
Physical communication line
Layered network Architecture SYS
B
P3P2P1
2 1
3 2 1
Physical communication line
3
N+1 N N-1
N+1 N N-1Pn-1
Pn
Pn+1
SYSA
interfact
The way that the interaction between the layers actually takes place is that each one requests services from the layer above it
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services The way that the interaction between the layers actually takes place is that each one requests services from the layer above itEach layer provides services to the next higher layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Service PrimitivesPrimitiv
eMeaning
Request An Entity wants the service to do some work
Indication
An Entity is to be informed about an event
Response
An Entity wants to respond to an event
Confirm The Response to an eariler request has come back
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
服务用户( N+1 )
服务提供者( N )系统 A 服务用户
( N+1 )服务提供者
( N )系统 B
无需证实Request
Indication
RequestIndication
Response
Confirm
需证实PDU
Relations among Service Primitives
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
电话系统工作示例例如张三打电话请李四吃饭服务提供者为电话局 ① CONNECT request 张三拨李四的电话号码 ② CONNECT i ndi cati on 李四的电话振铃 ③ CONNECT response 李四摘机 ④ CONNECT confi rm 张三听到振铃停止知道有人应答 ⑤ DATA request 张三说话发出邀请 ⑥ DATA i ndi cati on 李四听到张三的邀请 ⑦ DATA request 李四说话接受邀请 ⑧ DATA i ndi cati on 张三听到李四的答复 ⑨ DI SCONNECT request 李四挂机 ⑩ DI SCONNECT i ndi cat i on 张三听到李四挂机也挂机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Protocols can provide a service for upper layer
Protocols is ldquolevelrdquo But Services is ldquoVertical rdquo Service is adopted by the lower layer of
interface Functions is the internal activities
Services interface protocols and functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services to Protocols Relationship
The relationship between a service and a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layers of the ISOrsquos OSI reference model The layers of the OSI model on each node
communicate with each other
A layer in the OSI model represents a compon-ent of the total process of communicating T
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Actual communication passes down through the layers on the sending node and then up through the layers on the receiving node
Chapter 3 Network Architetures and Standarts
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X25The first three layers of the OSI model have been standardized and together are called the X25 standard for data transmission
Chapter 3 Network Architetures and Standarts
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GOSIP government open system Interconnetion Protocola subset of the OSI model that vendors must support if they want to sell network services or equipment to the US governmentGOSIP is neither a new architecture nor a New standardIt is a more precise specification of what parts of the OSI model the government will use
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392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
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Typical equipment
What are the Physical Layer components on my computer
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Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
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LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
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Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
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Network Interface Card Bridge
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LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
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LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
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Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
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LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
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Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
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LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
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Direct and Indirect Methods of Translation Concept of Encryption and Decryption
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Data Compression Methods Run-Length Encoding
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LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
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OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
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Typical equipmentGateway proxy firewall
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Summary of Layer Functions
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OSI 模型是协助网络检修人员识别网络问题一种理想的框架
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310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
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The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
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TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
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A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
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PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
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TCPIP and the OSI Model
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Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
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Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
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UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
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Some Protocols in TCPIP Suite
Internet
Transport
App
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A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
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311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
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The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
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312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
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IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
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OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
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The ATM reference model
Chapter 3 Network Architetures and Standarts
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NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
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Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
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A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
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3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
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OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
People who have a strong networking background see the computer as a tool to enhance a network`s capability
One
Tend to wait for standards and follow them closely
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Figure 3-1 Two different views of the relative roles of networks and computers
Those who have a strong computer background tend to focus on what can be done with software or specially designed circuit chips for computers
They forge ahead of the standards-making process
Two
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Purport While neither viewpoint is wrong it leads to differing philosophiesBoth are legitimate and have their place
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
35 STANDS AND STANDS-MAKING ORGANIZATIONS Because of the recognized need for common international standards there is a great deal of cooperation among communications standards making organizations Data communication standards are more complicated than Voice communication standardsEarly standards were mostly electrical in nature The standards-setting process is slowWriting standards is difficult work
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
ITU (The International Telecommunication Union)
1865 in the U S was established in Paris 1947 as part of the United Nations members from 188 countries headquartered in Geneva SwitzerlandThe most important telecommunications standards-setting organization in the world is the ITU ITU-T has created two sets of standards for the electrical connection of terminals to communications networks
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
ISOInternational Standards OrganizationDonrsquot confuse the OSI with ISO and IOSISO means the international organization for standardizationIOS (internet operation system) is used in CISCO systemrsquos routers and switches
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Figure of the organizations involved in setting telecommunications standards or in passing input to the standards-setting bodies
The American National Standards Institute (ANSI) is not involved in setting communications standards The official TCPIP model is now maintained by the IETFAll communications standards are developed by one organization the ISOF
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
36 V STANDARD XSTANDARD
The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called the V and X standards
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Vstandards define the connection of digital equipment to the PSTN`s analog linesV32 V33 V42 standard for the use of telephone transmission of data made a clear statement XstandardsDefine the connection of digital equipment to digital linesEG X25 X400 X500
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
37 ADVANTAGES AND DISADVANTAGES OF STANDARDS
Adv Standards allow products from multiple vendors to be connected to one another and to communicate
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
disadvanceThe standards-setting process is slowStandards tend to freeze technologyMultiple conflicting standardsThe standards-setting process can occur quickly(Writing standards is relatively easy ) when an architecture is in placeF
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
38 COMMUNICATIONS ARCHITECTURESISO and ITU-T developed OSI reference model in 1978OSI-RM Open Systems Interconnection reference modelThe standards development process took so long that the osi model never came into widespread useIt is the standard reference point by which data communications networks are described
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
39 THE ISO`S OSI REFERENCE MODEL391 Objective Provide a basis for interconnecting dissimilar systems for the purpose of information exchange Define communications rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI and most network architecture use a layered approach A layer in the OSI RM represents a component of the total process of communicating Each one layer requests services from the layer below it N layer Provide services to N+1 layer The same network any two-system must have the same level The actual physical communication completed only in the bottom layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
1) Layering forces the modularization of function Dealing with complex systemsThe output of laying definition process is standardseases maintenance updating of systemOne layer can be changed without affecting other layersDifferent implementations can be substituted relativelyTransparently
Why layering
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layer Layer requires reasonably sophisticated software and hardware at each end of the connection
前置处理机CCP
中央主机 中央主机中央主机
前置处理机
前置处理机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The philosopher-translator-Secretary architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
CN scientists
CN Translate
CNTelegrafisten
Telex machine
JP scientists
JP Translate
JPTelegrafisten
Telex machine
protocol
protocol
protocol
protocol
Scientific opinion
English
Letters
Telegraph code
Example Scientific exchange layered
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Architecture Layered principle Basic concept
Entity Can send or receive any information of hardware software process Peer layer Two different systems the same level Interface Interaction between the two neighboring layerSERVE for the upper classes a capacity to provide services through the interface Protocol Communication both in communication must comply with the rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
SYSA
SYSBentity Pee
r layerpeer
entity
server
Physical communication line
Layered network Architecture SYS
B
P3P2P1
2 1
3 2 1
Physical communication line
3
N+1 N N-1
N+1 N N-1Pn-1
Pn
Pn+1
SYSA
interfact
The way that the interaction between the layers actually takes place is that each one requests services from the layer above it
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services The way that the interaction between the layers actually takes place is that each one requests services from the layer above itEach layer provides services to the next higher layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Service PrimitivesPrimitiv
eMeaning
Request An Entity wants the service to do some work
Indication
An Entity is to be informed about an event
Response
An Entity wants to respond to an event
Confirm The Response to an eariler request has come back
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
服务用户( N+1 )
服务提供者( N )系统 A 服务用户
( N+1 )服务提供者
( N )系统 B
无需证实Request
Indication
RequestIndication
Response
Confirm
需证实PDU
Relations among Service Primitives
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
电话系统工作示例例如张三打电话请李四吃饭服务提供者为电话局 ① CONNECT request 张三拨李四的电话号码 ② CONNECT i ndi cati on 李四的电话振铃 ③ CONNECT response 李四摘机 ④ CONNECT confi rm 张三听到振铃停止知道有人应答 ⑤ DATA request 张三说话发出邀请 ⑥ DATA i ndi cati on 李四听到张三的邀请 ⑦ DATA request 李四说话接受邀请 ⑧ DATA i ndi cati on 张三听到李四的答复 ⑨ DI SCONNECT request 李四挂机 ⑩ DI SCONNECT i ndi cat i on 张三听到李四挂机也挂机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Protocols can provide a service for upper layer
Protocols is ldquolevelrdquo But Services is ldquoVertical rdquo Service is adopted by the lower layer of
interface Functions is the internal activities
Services interface protocols and functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services to Protocols Relationship
The relationship between a service and a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layers of the ISOrsquos OSI reference model The layers of the OSI model on each node
communicate with each other
A layer in the OSI model represents a compon-ent of the total process of communicating T
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Actual communication passes down through the layers on the sending node and then up through the layers on the receiving node
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
X25The first three layers of the OSI model have been standardized and together are called the X25 standard for data transmission
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
GOSIP government open system Interconnetion Protocola subset of the OSI model that vendors must support if they want to sell network services or equipment to the US governmentGOSIP is neither a new architecture nor a New standardIt is a more precise specification of what parts of the OSI model the government will use
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipment
What are the Physical Layer components on my computer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
Figure 3-1 Two different views of the relative roles of networks and computers
Those who have a strong computer background tend to focus on what can be done with software or specially designed circuit chips for computers
They forge ahead of the standards-making process
Two
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Purport While neither viewpoint is wrong it leads to differing philosophiesBoth are legitimate and have their place
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
35 STANDS AND STANDS-MAKING ORGANIZATIONS Because of the recognized need for common international standards there is a great deal of cooperation among communications standards making organizations Data communication standards are more complicated than Voice communication standardsEarly standards were mostly electrical in nature The standards-setting process is slowWriting standards is difficult work
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
ITU (The International Telecommunication Union)
1865 in the U S was established in Paris 1947 as part of the United Nations members from 188 countries headquartered in Geneva SwitzerlandThe most important telecommunications standards-setting organization in the world is the ITU ITU-T has created two sets of standards for the electrical connection of terminals to communications networks
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
ISOInternational Standards OrganizationDonrsquot confuse the OSI with ISO and IOSISO means the international organization for standardizationIOS (internet operation system) is used in CISCO systemrsquos routers and switches
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Figure of the organizations involved in setting telecommunications standards or in passing input to the standards-setting bodies
The American National Standards Institute (ANSI) is not involved in setting communications standards The official TCPIP model is now maintained by the IETFAll communications standards are developed by one organization the ISOF
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
36 V STANDARD XSTANDARD
The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called the V and X standards
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Vstandards define the connection of digital equipment to the PSTN`s analog linesV32 V33 V42 standard for the use of telephone transmission of data made a clear statement XstandardsDefine the connection of digital equipment to digital linesEG X25 X400 X500
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
37 ADVANTAGES AND DISADVANTAGES OF STANDARDS
Adv Standards allow products from multiple vendors to be connected to one another and to communicate
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
disadvanceThe standards-setting process is slowStandards tend to freeze technologyMultiple conflicting standardsThe standards-setting process can occur quickly(Writing standards is relatively easy ) when an architecture is in placeF
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
38 COMMUNICATIONS ARCHITECTURESISO and ITU-T developed OSI reference model in 1978OSI-RM Open Systems Interconnection reference modelThe standards development process took so long that the osi model never came into widespread useIt is the standard reference point by which data communications networks are described
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
39 THE ISO`S OSI REFERENCE MODEL391 Objective Provide a basis for interconnecting dissimilar systems for the purpose of information exchange Define communications rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI and most network architecture use a layered approach A layer in the OSI RM represents a component of the total process of communicating Each one layer requests services from the layer below it N layer Provide services to N+1 layer The same network any two-system must have the same level The actual physical communication completed only in the bottom layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
1) Layering forces the modularization of function Dealing with complex systemsThe output of laying definition process is standardseases maintenance updating of systemOne layer can be changed without affecting other layersDifferent implementations can be substituted relativelyTransparently
Why layering
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layer Layer requires reasonably sophisticated software and hardware at each end of the connection
前置处理机CCP
中央主机 中央主机中央主机
前置处理机
前置处理机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The philosopher-translator-Secretary architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
CN scientists
CN Translate
CNTelegrafisten
Telex machine
JP scientists
JP Translate
JPTelegrafisten
Telex machine
protocol
protocol
protocol
protocol
Scientific opinion
English
Letters
Telegraph code
Example Scientific exchange layered
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Architecture Layered principle Basic concept
Entity Can send or receive any information of hardware software process Peer layer Two different systems the same level Interface Interaction between the two neighboring layerSERVE for the upper classes a capacity to provide services through the interface Protocol Communication both in communication must comply with the rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
SYSA
SYSBentity Pee
r layerpeer
entity
server
Physical communication line
Layered network Architecture SYS
B
P3P2P1
2 1
3 2 1
Physical communication line
3
N+1 N N-1
N+1 N N-1Pn-1
Pn
Pn+1
SYSA
interfact
The way that the interaction between the layers actually takes place is that each one requests services from the layer above it
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services The way that the interaction between the layers actually takes place is that each one requests services from the layer above itEach layer provides services to the next higher layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Service PrimitivesPrimitiv
eMeaning
Request An Entity wants the service to do some work
Indication
An Entity is to be informed about an event
Response
An Entity wants to respond to an event
Confirm The Response to an eariler request has come back
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
服务用户( N+1 )
服务提供者( N )系统 A 服务用户
( N+1 )服务提供者
( N )系统 B
无需证实Request
Indication
RequestIndication
Response
Confirm
需证实PDU
Relations among Service Primitives
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
电话系统工作示例例如张三打电话请李四吃饭服务提供者为电话局 ① CONNECT request 张三拨李四的电话号码 ② CONNECT i ndi cati on 李四的电话振铃 ③ CONNECT response 李四摘机 ④ CONNECT confi rm 张三听到振铃停止知道有人应答 ⑤ DATA request 张三说话发出邀请 ⑥ DATA i ndi cati on 李四听到张三的邀请 ⑦ DATA request 李四说话接受邀请 ⑧ DATA i ndi cati on 张三听到李四的答复 ⑨ DI SCONNECT request 李四挂机 ⑩ DI SCONNECT i ndi cat i on 张三听到李四挂机也挂机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Protocols can provide a service for upper layer
Protocols is ldquolevelrdquo But Services is ldquoVertical rdquo Service is adopted by the lower layer of
interface Functions is the internal activities
Services interface protocols and functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services to Protocols Relationship
The relationship between a service and a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layers of the ISOrsquos OSI reference model The layers of the OSI model on each node
communicate with each other
A layer in the OSI model represents a compon-ent of the total process of communicating T
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Actual communication passes down through the layers on the sending node and then up through the layers on the receiving node
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
X25The first three layers of the OSI model have been standardized and together are called the X25 standard for data transmission
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
GOSIP government open system Interconnetion Protocola subset of the OSI model that vendors must support if they want to sell network services or equipment to the US governmentGOSIP is neither a new architecture nor a New standardIt is a more precise specification of what parts of the OSI model the government will use
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipment
What are the Physical Layer components on my computer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
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OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
Purport While neither viewpoint is wrong it leads to differing philosophiesBoth are legitimate and have their place
Chapter 3 Network Architetures and Standarts
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35 STANDS AND STANDS-MAKING ORGANIZATIONS Because of the recognized need for common international standards there is a great deal of cooperation among communications standards making organizations Data communication standards are more complicated than Voice communication standardsEarly standards were mostly electrical in nature The standards-setting process is slowWriting standards is difficult work
Chapter 3 Network Architetures and Standarts
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ITU (The International Telecommunication Union)
1865 in the U S was established in Paris 1947 as part of the United Nations members from 188 countries headquartered in Geneva SwitzerlandThe most important telecommunications standards-setting organization in the world is the ITU ITU-T has created two sets of standards for the electrical connection of terminals to communications networks
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
ISOInternational Standards OrganizationDonrsquot confuse the OSI with ISO and IOSISO means the international organization for standardizationIOS (internet operation system) is used in CISCO systemrsquos routers and switches
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Figure of the organizations involved in setting telecommunications standards or in passing input to the standards-setting bodies
The American National Standards Institute (ANSI) is not involved in setting communications standards The official TCPIP model is now maintained by the IETFAll communications standards are developed by one organization the ISOF
Chapter 3 Network Architetures and Standarts
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36 V STANDARD XSTANDARD
The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called the V and X standards
Chapter 3 Network Architetures and Standarts
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Vstandards define the connection of digital equipment to the PSTN`s analog linesV32 V33 V42 standard for the use of telephone transmission of data made a clear statement XstandardsDefine the connection of digital equipment to digital linesEG X25 X400 X500
Chapter 3 Network Architetures and Standarts
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37 ADVANTAGES AND DISADVANTAGES OF STANDARDS
Adv Standards allow products from multiple vendors to be connected to one another and to communicate
Chapter 3 Network Architetures and Standarts
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disadvanceThe standards-setting process is slowStandards tend to freeze technologyMultiple conflicting standardsThe standards-setting process can occur quickly(Writing standards is relatively easy ) when an architecture is in placeF
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
38 COMMUNICATIONS ARCHITECTURESISO and ITU-T developed OSI reference model in 1978OSI-RM Open Systems Interconnection reference modelThe standards development process took so long that the osi model never came into widespread useIt is the standard reference point by which data communications networks are described
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
39 THE ISO`S OSI REFERENCE MODEL391 Objective Provide a basis for interconnecting dissimilar systems for the purpose of information exchange Define communications rules
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OSI and most network architecture use a layered approach A layer in the OSI RM represents a component of the total process of communicating Each one layer requests services from the layer below it N layer Provide services to N+1 layer The same network any two-system must have the same level The actual physical communication completed only in the bottom layer
Chapter 3 Network Architetures and Standarts
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1) Layering forces the modularization of function Dealing with complex systemsThe output of laying definition process is standardseases maintenance updating of systemOne layer can be changed without affecting other layersDifferent implementations can be substituted relativelyTransparently
Why layering
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layer Layer requires reasonably sophisticated software and hardware at each end of the connection
前置处理机CCP
中央主机 中央主机中央主机
前置处理机
前置处理机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The philosopher-translator-Secretary architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
CN scientists
CN Translate
CNTelegrafisten
Telex machine
JP scientists
JP Translate
JPTelegrafisten
Telex machine
protocol
protocol
protocol
protocol
Scientific opinion
English
Letters
Telegraph code
Example Scientific exchange layered
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Architecture Layered principle Basic concept
Entity Can send or receive any information of hardware software process Peer layer Two different systems the same level Interface Interaction between the two neighboring layerSERVE for the upper classes a capacity to provide services through the interface Protocol Communication both in communication must comply with the rules
Chapter 3 Network Architetures and Standarts
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SYSA
SYSBentity Pee
r layerpeer
entity
server
Physical communication line
Layered network Architecture SYS
B
P3P2P1
2 1
3 2 1
Physical communication line
3
N+1 N N-1
N+1 N N-1Pn-1
Pn
Pn+1
SYSA
interfact
The way that the interaction between the layers actually takes place is that each one requests services from the layer above it
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services The way that the interaction between the layers actually takes place is that each one requests services from the layer above itEach layer provides services to the next higher layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Service PrimitivesPrimitiv
eMeaning
Request An Entity wants the service to do some work
Indication
An Entity is to be informed about an event
Response
An Entity wants to respond to an event
Confirm The Response to an eariler request has come back
Chapter 3 Network Architetures and Standarts
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服务用户( N+1 )
服务提供者( N )系统 A 服务用户
( N+1 )服务提供者
( N )系统 B
无需证实Request
Indication
RequestIndication
Response
Confirm
需证实PDU
Relations among Service Primitives
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
电话系统工作示例例如张三打电话请李四吃饭服务提供者为电话局 ① CONNECT request 张三拨李四的电话号码 ② CONNECT i ndi cati on 李四的电话振铃 ③ CONNECT response 李四摘机 ④ CONNECT confi rm 张三听到振铃停止知道有人应答 ⑤ DATA request 张三说话发出邀请 ⑥ DATA i ndi cati on 李四听到张三的邀请 ⑦ DATA request 李四说话接受邀请 ⑧ DATA i ndi cati on 张三听到李四的答复 ⑨ DI SCONNECT request 李四挂机 ⑩ DI SCONNECT i ndi cat i on 张三听到李四挂机也挂机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Protocols can provide a service for upper layer
Protocols is ldquolevelrdquo But Services is ldquoVertical rdquo Service is adopted by the lower layer of
interface Functions is the internal activities
Services interface protocols and functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services to Protocols Relationship
The relationship between a service and a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layers of the ISOrsquos OSI reference model The layers of the OSI model on each node
communicate with each other
A layer in the OSI model represents a compon-ent of the total process of communicating T
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Actual communication passes down through the layers on the sending node and then up through the layers on the receiving node
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
X25The first three layers of the OSI model have been standardized and together are called the X25 standard for data transmission
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
GOSIP government open system Interconnetion Protocola subset of the OSI model that vendors must support if they want to sell network services or equipment to the US governmentGOSIP is neither a new architecture nor a New standardIt is a more precise specification of what parts of the OSI model the government will use
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipment
What are the Physical Layer components on my computer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
35 STANDS AND STANDS-MAKING ORGANIZATIONS Because of the recognized need for common international standards there is a great deal of cooperation among communications standards making organizations Data communication standards are more complicated than Voice communication standardsEarly standards were mostly electrical in nature The standards-setting process is slowWriting standards is difficult work
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
ITU (The International Telecommunication Union)
1865 in the U S was established in Paris 1947 as part of the United Nations members from 188 countries headquartered in Geneva SwitzerlandThe most important telecommunications standards-setting organization in the world is the ITU ITU-T has created two sets of standards for the electrical connection of terminals to communications networks
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
ISOInternational Standards OrganizationDonrsquot confuse the OSI with ISO and IOSISO means the international organization for standardizationIOS (internet operation system) is used in CISCO systemrsquos routers and switches
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Figure of the organizations involved in setting telecommunications standards or in passing input to the standards-setting bodies
The American National Standards Institute (ANSI) is not involved in setting communications standards The official TCPIP model is now maintained by the IETFAll communications standards are developed by one organization the ISOF
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
36 V STANDARD XSTANDARD
The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called the V and X standards
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Vstandards define the connection of digital equipment to the PSTN`s analog linesV32 V33 V42 standard for the use of telephone transmission of data made a clear statement XstandardsDefine the connection of digital equipment to digital linesEG X25 X400 X500
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
37 ADVANTAGES AND DISADVANTAGES OF STANDARDS
Adv Standards allow products from multiple vendors to be connected to one another and to communicate
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
disadvanceThe standards-setting process is slowStandards tend to freeze technologyMultiple conflicting standardsThe standards-setting process can occur quickly(Writing standards is relatively easy ) when an architecture is in placeF
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
38 COMMUNICATIONS ARCHITECTURESISO and ITU-T developed OSI reference model in 1978OSI-RM Open Systems Interconnection reference modelThe standards development process took so long that the osi model never came into widespread useIt is the standard reference point by which data communications networks are described
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
39 THE ISO`S OSI REFERENCE MODEL391 Objective Provide a basis for interconnecting dissimilar systems for the purpose of information exchange Define communications rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI and most network architecture use a layered approach A layer in the OSI RM represents a component of the total process of communicating Each one layer requests services from the layer below it N layer Provide services to N+1 layer The same network any two-system must have the same level The actual physical communication completed only in the bottom layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
1) Layering forces the modularization of function Dealing with complex systemsThe output of laying definition process is standardseases maintenance updating of systemOne layer can be changed without affecting other layersDifferent implementations can be substituted relativelyTransparently
Why layering
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layer Layer requires reasonably sophisticated software and hardware at each end of the connection
前置处理机CCP
中央主机 中央主机中央主机
前置处理机
前置处理机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The philosopher-translator-Secretary architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
CN scientists
CN Translate
CNTelegrafisten
Telex machine
JP scientists
JP Translate
JPTelegrafisten
Telex machine
protocol
protocol
protocol
protocol
Scientific opinion
English
Letters
Telegraph code
Example Scientific exchange layered
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Architecture Layered principle Basic concept
Entity Can send or receive any information of hardware software process Peer layer Two different systems the same level Interface Interaction between the two neighboring layerSERVE for the upper classes a capacity to provide services through the interface Protocol Communication both in communication must comply with the rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
SYSA
SYSBentity Pee
r layerpeer
entity
server
Physical communication line
Layered network Architecture SYS
B
P3P2P1
2 1
3 2 1
Physical communication line
3
N+1 N N-1
N+1 N N-1Pn-1
Pn
Pn+1
SYSA
interfact
The way that the interaction between the layers actually takes place is that each one requests services from the layer above it
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services The way that the interaction between the layers actually takes place is that each one requests services from the layer above itEach layer provides services to the next higher layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Service PrimitivesPrimitiv
eMeaning
Request An Entity wants the service to do some work
Indication
An Entity is to be informed about an event
Response
An Entity wants to respond to an event
Confirm The Response to an eariler request has come back
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
服务用户( N+1 )
服务提供者( N )系统 A 服务用户
( N+1 )服务提供者
( N )系统 B
无需证实Request
Indication
RequestIndication
Response
Confirm
需证实PDU
Relations among Service Primitives
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
电话系统工作示例例如张三打电话请李四吃饭服务提供者为电话局 ① CONNECT request 张三拨李四的电话号码 ② CONNECT i ndi cati on 李四的电话振铃 ③ CONNECT response 李四摘机 ④ CONNECT confi rm 张三听到振铃停止知道有人应答 ⑤ DATA request 张三说话发出邀请 ⑥ DATA i ndi cati on 李四听到张三的邀请 ⑦ DATA request 李四说话接受邀请 ⑧ DATA i ndi cati on 张三听到李四的答复 ⑨ DI SCONNECT request 李四挂机 ⑩ DI SCONNECT i ndi cat i on 张三听到李四挂机也挂机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Protocols can provide a service for upper layer
Protocols is ldquolevelrdquo But Services is ldquoVertical rdquo Service is adopted by the lower layer of
interface Functions is the internal activities
Services interface protocols and functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services to Protocols Relationship
The relationship between a service and a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layers of the ISOrsquos OSI reference model The layers of the OSI model on each node
communicate with each other
A layer in the OSI model represents a compon-ent of the total process of communicating T
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Actual communication passes down through the layers on the sending node and then up through the layers on the receiving node
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
X25The first three layers of the OSI model have been standardized and together are called the X25 standard for data transmission
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
GOSIP government open system Interconnetion Protocola subset of the OSI model that vendors must support if they want to sell network services or equipment to the US governmentGOSIP is neither a new architecture nor a New standardIt is a more precise specification of what parts of the OSI model the government will use
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipment
What are the Physical Layer components on my computer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
ITU (The International Telecommunication Union)
1865 in the U S was established in Paris 1947 as part of the United Nations members from 188 countries headquartered in Geneva SwitzerlandThe most important telecommunications standards-setting organization in the world is the ITU ITU-T has created two sets of standards for the electrical connection of terminals to communications networks
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
ISOInternational Standards OrganizationDonrsquot confuse the OSI with ISO and IOSISO means the international organization for standardizationIOS (internet operation system) is used in CISCO systemrsquos routers and switches
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Figure of the organizations involved in setting telecommunications standards or in passing input to the standards-setting bodies
The American National Standards Institute (ANSI) is not involved in setting communications standards The official TCPIP model is now maintained by the IETFAll communications standards are developed by one organization the ISOF
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
36 V STANDARD XSTANDARD
The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called the V and X standards
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Vstandards define the connection of digital equipment to the PSTN`s analog linesV32 V33 V42 standard for the use of telephone transmission of data made a clear statement XstandardsDefine the connection of digital equipment to digital linesEG X25 X400 X500
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
37 ADVANTAGES AND DISADVANTAGES OF STANDARDS
Adv Standards allow products from multiple vendors to be connected to one another and to communicate
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
disadvanceThe standards-setting process is slowStandards tend to freeze technologyMultiple conflicting standardsThe standards-setting process can occur quickly(Writing standards is relatively easy ) when an architecture is in placeF
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
38 COMMUNICATIONS ARCHITECTURESISO and ITU-T developed OSI reference model in 1978OSI-RM Open Systems Interconnection reference modelThe standards development process took so long that the osi model never came into widespread useIt is the standard reference point by which data communications networks are described
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
39 THE ISO`S OSI REFERENCE MODEL391 Objective Provide a basis for interconnecting dissimilar systems for the purpose of information exchange Define communications rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI and most network architecture use a layered approach A layer in the OSI RM represents a component of the total process of communicating Each one layer requests services from the layer below it N layer Provide services to N+1 layer The same network any two-system must have the same level The actual physical communication completed only in the bottom layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
1) Layering forces the modularization of function Dealing with complex systemsThe output of laying definition process is standardseases maintenance updating of systemOne layer can be changed without affecting other layersDifferent implementations can be substituted relativelyTransparently
Why layering
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layer Layer requires reasonably sophisticated software and hardware at each end of the connection
前置处理机CCP
中央主机 中央主机中央主机
前置处理机
前置处理机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The philosopher-translator-Secretary architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
CN scientists
CN Translate
CNTelegrafisten
Telex machine
JP scientists
JP Translate
JPTelegrafisten
Telex machine
protocol
protocol
protocol
protocol
Scientific opinion
English
Letters
Telegraph code
Example Scientific exchange layered
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Architecture Layered principle Basic concept
Entity Can send or receive any information of hardware software process Peer layer Two different systems the same level Interface Interaction between the two neighboring layerSERVE for the upper classes a capacity to provide services through the interface Protocol Communication both in communication must comply with the rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
SYSA
SYSBentity Pee
r layerpeer
entity
server
Physical communication line
Layered network Architecture SYS
B
P3P2P1
2 1
3 2 1
Physical communication line
3
N+1 N N-1
N+1 N N-1Pn-1
Pn
Pn+1
SYSA
interfact
The way that the interaction between the layers actually takes place is that each one requests services from the layer above it
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services The way that the interaction between the layers actually takes place is that each one requests services from the layer above itEach layer provides services to the next higher layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Service PrimitivesPrimitiv
eMeaning
Request An Entity wants the service to do some work
Indication
An Entity is to be informed about an event
Response
An Entity wants to respond to an event
Confirm The Response to an eariler request has come back
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
服务用户( N+1 )
服务提供者( N )系统 A 服务用户
( N+1 )服务提供者
( N )系统 B
无需证实Request
Indication
RequestIndication
Response
Confirm
需证实PDU
Relations among Service Primitives
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
电话系统工作示例例如张三打电话请李四吃饭服务提供者为电话局 ① CONNECT request 张三拨李四的电话号码 ② CONNECT i ndi cati on 李四的电话振铃 ③ CONNECT response 李四摘机 ④ CONNECT confi rm 张三听到振铃停止知道有人应答 ⑤ DATA request 张三说话发出邀请 ⑥ DATA i ndi cati on 李四听到张三的邀请 ⑦ DATA request 李四说话接受邀请 ⑧ DATA i ndi cati on 张三听到李四的答复 ⑨ DI SCONNECT request 李四挂机 ⑩ DI SCONNECT i ndi cat i on 张三听到李四挂机也挂机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Protocols can provide a service for upper layer
Protocols is ldquolevelrdquo But Services is ldquoVertical rdquo Service is adopted by the lower layer of
interface Functions is the internal activities
Services interface protocols and functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services to Protocols Relationship
The relationship between a service and a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layers of the ISOrsquos OSI reference model The layers of the OSI model on each node
communicate with each other
A layer in the OSI model represents a compon-ent of the total process of communicating T
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Actual communication passes down through the layers on the sending node and then up through the layers on the receiving node
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
X25The first three layers of the OSI model have been standardized and together are called the X25 standard for data transmission
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
GOSIP government open system Interconnetion Protocola subset of the OSI model that vendors must support if they want to sell network services or equipment to the US governmentGOSIP is neither a new architecture nor a New standardIt is a more precise specification of what parts of the OSI model the government will use
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipment
What are the Physical Layer components on my computer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
ISOInternational Standards OrganizationDonrsquot confuse the OSI with ISO and IOSISO means the international organization for standardizationIOS (internet operation system) is used in CISCO systemrsquos routers and switches
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Figure of the organizations involved in setting telecommunications standards or in passing input to the standards-setting bodies
The American National Standards Institute (ANSI) is not involved in setting communications standards The official TCPIP model is now maintained by the IETFAll communications standards are developed by one organization the ISOF
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
36 V STANDARD XSTANDARD
The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called the V and X standards
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Vstandards define the connection of digital equipment to the PSTN`s analog linesV32 V33 V42 standard for the use of telephone transmission of data made a clear statement XstandardsDefine the connection of digital equipment to digital linesEG X25 X400 X500
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
37 ADVANTAGES AND DISADVANTAGES OF STANDARDS
Adv Standards allow products from multiple vendors to be connected to one another and to communicate
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
disadvanceThe standards-setting process is slowStandards tend to freeze technologyMultiple conflicting standardsThe standards-setting process can occur quickly(Writing standards is relatively easy ) when an architecture is in placeF
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
38 COMMUNICATIONS ARCHITECTURESISO and ITU-T developed OSI reference model in 1978OSI-RM Open Systems Interconnection reference modelThe standards development process took so long that the osi model never came into widespread useIt is the standard reference point by which data communications networks are described
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
39 THE ISO`S OSI REFERENCE MODEL391 Objective Provide a basis for interconnecting dissimilar systems for the purpose of information exchange Define communications rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI and most network architecture use a layered approach A layer in the OSI RM represents a component of the total process of communicating Each one layer requests services from the layer below it N layer Provide services to N+1 layer The same network any two-system must have the same level The actual physical communication completed only in the bottom layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
1) Layering forces the modularization of function Dealing with complex systemsThe output of laying definition process is standardseases maintenance updating of systemOne layer can be changed without affecting other layersDifferent implementations can be substituted relativelyTransparently
Why layering
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layer Layer requires reasonably sophisticated software and hardware at each end of the connection
前置处理机CCP
中央主机 中央主机中央主机
前置处理机
前置处理机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The philosopher-translator-Secretary architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
CN scientists
CN Translate
CNTelegrafisten
Telex machine
JP scientists
JP Translate
JPTelegrafisten
Telex machine
protocol
protocol
protocol
protocol
Scientific opinion
English
Letters
Telegraph code
Example Scientific exchange layered
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Architecture Layered principle Basic concept
Entity Can send or receive any information of hardware software process Peer layer Two different systems the same level Interface Interaction between the two neighboring layerSERVE for the upper classes a capacity to provide services through the interface Protocol Communication both in communication must comply with the rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
SYSA
SYSBentity Pee
r layerpeer
entity
server
Physical communication line
Layered network Architecture SYS
B
P3P2P1
2 1
3 2 1
Physical communication line
3
N+1 N N-1
N+1 N N-1Pn-1
Pn
Pn+1
SYSA
interfact
The way that the interaction between the layers actually takes place is that each one requests services from the layer above it
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services The way that the interaction between the layers actually takes place is that each one requests services from the layer above itEach layer provides services to the next higher layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Service PrimitivesPrimitiv
eMeaning
Request An Entity wants the service to do some work
Indication
An Entity is to be informed about an event
Response
An Entity wants to respond to an event
Confirm The Response to an eariler request has come back
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
服务用户( N+1 )
服务提供者( N )系统 A 服务用户
( N+1 )服务提供者
( N )系统 B
无需证实Request
Indication
RequestIndication
Response
Confirm
需证实PDU
Relations among Service Primitives
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
电话系统工作示例例如张三打电话请李四吃饭服务提供者为电话局 ① CONNECT request 张三拨李四的电话号码 ② CONNECT i ndi cati on 李四的电话振铃 ③ CONNECT response 李四摘机 ④ CONNECT confi rm 张三听到振铃停止知道有人应答 ⑤ DATA request 张三说话发出邀请 ⑥ DATA i ndi cati on 李四听到张三的邀请 ⑦ DATA request 李四说话接受邀请 ⑧ DATA i ndi cati on 张三听到李四的答复 ⑨ DI SCONNECT request 李四挂机 ⑩ DI SCONNECT i ndi cat i on 张三听到李四挂机也挂机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Protocols can provide a service for upper layer
Protocols is ldquolevelrdquo But Services is ldquoVertical rdquo Service is adopted by the lower layer of
interface Functions is the internal activities
Services interface protocols and functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services to Protocols Relationship
The relationship between a service and a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layers of the ISOrsquos OSI reference model The layers of the OSI model on each node
communicate with each other
A layer in the OSI model represents a compon-ent of the total process of communicating T
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Actual communication passes down through the layers on the sending node and then up through the layers on the receiving node
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
X25The first three layers of the OSI model have been standardized and together are called the X25 standard for data transmission
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
GOSIP government open system Interconnetion Protocola subset of the OSI model that vendors must support if they want to sell network services or equipment to the US governmentGOSIP is neither a new architecture nor a New standardIt is a more precise specification of what parts of the OSI model the government will use
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipment
What are the Physical Layer components on my computer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
Figure of the organizations involved in setting telecommunications standards or in passing input to the standards-setting bodies
The American National Standards Institute (ANSI) is not involved in setting communications standards The official TCPIP model is now maintained by the IETFAll communications standards are developed by one organization the ISOF
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
36 V STANDARD XSTANDARD
The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called the V and X standards
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Vstandards define the connection of digital equipment to the PSTN`s analog linesV32 V33 V42 standard for the use of telephone transmission of data made a clear statement XstandardsDefine the connection of digital equipment to digital linesEG X25 X400 X500
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
37 ADVANTAGES AND DISADVANTAGES OF STANDARDS
Adv Standards allow products from multiple vendors to be connected to one another and to communicate
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
disadvanceThe standards-setting process is slowStandards tend to freeze technologyMultiple conflicting standardsThe standards-setting process can occur quickly(Writing standards is relatively easy ) when an architecture is in placeF
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
38 COMMUNICATIONS ARCHITECTURESISO and ITU-T developed OSI reference model in 1978OSI-RM Open Systems Interconnection reference modelThe standards development process took so long that the osi model never came into widespread useIt is the standard reference point by which data communications networks are described
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
39 THE ISO`S OSI REFERENCE MODEL391 Objective Provide a basis for interconnecting dissimilar systems for the purpose of information exchange Define communications rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI and most network architecture use a layered approach A layer in the OSI RM represents a component of the total process of communicating Each one layer requests services from the layer below it N layer Provide services to N+1 layer The same network any two-system must have the same level The actual physical communication completed only in the bottom layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
1) Layering forces the modularization of function Dealing with complex systemsThe output of laying definition process is standardseases maintenance updating of systemOne layer can be changed without affecting other layersDifferent implementations can be substituted relativelyTransparently
Why layering
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layer Layer requires reasonably sophisticated software and hardware at each end of the connection
前置处理机CCP
中央主机 中央主机中央主机
前置处理机
前置处理机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The philosopher-translator-Secretary architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
CN scientists
CN Translate
CNTelegrafisten
Telex machine
JP scientists
JP Translate
JPTelegrafisten
Telex machine
protocol
protocol
protocol
protocol
Scientific opinion
English
Letters
Telegraph code
Example Scientific exchange layered
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Architecture Layered principle Basic concept
Entity Can send or receive any information of hardware software process Peer layer Two different systems the same level Interface Interaction between the two neighboring layerSERVE for the upper classes a capacity to provide services through the interface Protocol Communication both in communication must comply with the rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
SYSA
SYSBentity Pee
r layerpeer
entity
server
Physical communication line
Layered network Architecture SYS
B
P3P2P1
2 1
3 2 1
Physical communication line
3
N+1 N N-1
N+1 N N-1Pn-1
Pn
Pn+1
SYSA
interfact
The way that the interaction between the layers actually takes place is that each one requests services from the layer above it
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services The way that the interaction between the layers actually takes place is that each one requests services from the layer above itEach layer provides services to the next higher layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Service PrimitivesPrimitiv
eMeaning
Request An Entity wants the service to do some work
Indication
An Entity is to be informed about an event
Response
An Entity wants to respond to an event
Confirm The Response to an eariler request has come back
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
服务用户( N+1 )
服务提供者( N )系统 A 服务用户
( N+1 )服务提供者
( N )系统 B
无需证实Request
Indication
RequestIndication
Response
Confirm
需证实PDU
Relations among Service Primitives
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
电话系统工作示例例如张三打电话请李四吃饭服务提供者为电话局 ① CONNECT request 张三拨李四的电话号码 ② CONNECT i ndi cati on 李四的电话振铃 ③ CONNECT response 李四摘机 ④ CONNECT confi rm 张三听到振铃停止知道有人应答 ⑤ DATA request 张三说话发出邀请 ⑥ DATA i ndi cati on 李四听到张三的邀请 ⑦ DATA request 李四说话接受邀请 ⑧ DATA i ndi cati on 张三听到李四的答复 ⑨ DI SCONNECT request 李四挂机 ⑩ DI SCONNECT i ndi cat i on 张三听到李四挂机也挂机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Protocols can provide a service for upper layer
Protocols is ldquolevelrdquo But Services is ldquoVertical rdquo Service is adopted by the lower layer of
interface Functions is the internal activities
Services interface protocols and functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services to Protocols Relationship
The relationship between a service and a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layers of the ISOrsquos OSI reference model The layers of the OSI model on each node
communicate with each other
A layer in the OSI model represents a compon-ent of the total process of communicating T
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Actual communication passes down through the layers on the sending node and then up through the layers on the receiving node
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
X25The first three layers of the OSI model have been standardized and together are called the X25 standard for data transmission
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
GOSIP government open system Interconnetion Protocola subset of the OSI model that vendors must support if they want to sell network services or equipment to the US governmentGOSIP is neither a new architecture nor a New standardIt is a more precise specification of what parts of the OSI model the government will use
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipment
What are the Physical Layer components on my computer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
36 V STANDARD XSTANDARD
The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called the V and X standards
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Vstandards define the connection of digital equipment to the PSTN`s analog linesV32 V33 V42 standard for the use of telephone transmission of data made a clear statement XstandardsDefine the connection of digital equipment to digital linesEG X25 X400 X500
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
37 ADVANTAGES AND DISADVANTAGES OF STANDARDS
Adv Standards allow products from multiple vendors to be connected to one another and to communicate
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
disadvanceThe standards-setting process is slowStandards tend to freeze technologyMultiple conflicting standardsThe standards-setting process can occur quickly(Writing standards is relatively easy ) when an architecture is in placeF
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
38 COMMUNICATIONS ARCHITECTURESISO and ITU-T developed OSI reference model in 1978OSI-RM Open Systems Interconnection reference modelThe standards development process took so long that the osi model never came into widespread useIt is the standard reference point by which data communications networks are described
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
39 THE ISO`S OSI REFERENCE MODEL391 Objective Provide a basis for interconnecting dissimilar systems for the purpose of information exchange Define communications rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI and most network architecture use a layered approach A layer in the OSI RM represents a component of the total process of communicating Each one layer requests services from the layer below it N layer Provide services to N+1 layer The same network any two-system must have the same level The actual physical communication completed only in the bottom layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
1) Layering forces the modularization of function Dealing with complex systemsThe output of laying definition process is standardseases maintenance updating of systemOne layer can be changed without affecting other layersDifferent implementations can be substituted relativelyTransparently
Why layering
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layer Layer requires reasonably sophisticated software and hardware at each end of the connection
前置处理机CCP
中央主机 中央主机中央主机
前置处理机
前置处理机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The philosopher-translator-Secretary architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
CN scientists
CN Translate
CNTelegrafisten
Telex machine
JP scientists
JP Translate
JPTelegrafisten
Telex machine
protocol
protocol
protocol
protocol
Scientific opinion
English
Letters
Telegraph code
Example Scientific exchange layered
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Architecture Layered principle Basic concept
Entity Can send or receive any information of hardware software process Peer layer Two different systems the same level Interface Interaction between the two neighboring layerSERVE for the upper classes a capacity to provide services through the interface Protocol Communication both in communication must comply with the rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
SYSA
SYSBentity Pee
r layerpeer
entity
server
Physical communication line
Layered network Architecture SYS
B
P3P2P1
2 1
3 2 1
Physical communication line
3
N+1 N N-1
N+1 N N-1Pn-1
Pn
Pn+1
SYSA
interfact
The way that the interaction between the layers actually takes place is that each one requests services from the layer above it
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services The way that the interaction between the layers actually takes place is that each one requests services from the layer above itEach layer provides services to the next higher layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Service PrimitivesPrimitiv
eMeaning
Request An Entity wants the service to do some work
Indication
An Entity is to be informed about an event
Response
An Entity wants to respond to an event
Confirm The Response to an eariler request has come back
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
服务用户( N+1 )
服务提供者( N )系统 A 服务用户
( N+1 )服务提供者
( N )系统 B
无需证实Request
Indication
RequestIndication
Response
Confirm
需证实PDU
Relations among Service Primitives
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
电话系统工作示例例如张三打电话请李四吃饭服务提供者为电话局 ① CONNECT request 张三拨李四的电话号码 ② CONNECT i ndi cati on 李四的电话振铃 ③ CONNECT response 李四摘机 ④ CONNECT confi rm 张三听到振铃停止知道有人应答 ⑤ DATA request 张三说话发出邀请 ⑥ DATA i ndi cati on 李四听到张三的邀请 ⑦ DATA request 李四说话接受邀请 ⑧ DATA i ndi cati on 张三听到李四的答复 ⑨ DI SCONNECT request 李四挂机 ⑩ DI SCONNECT i ndi cat i on 张三听到李四挂机也挂机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Protocols can provide a service for upper layer
Protocols is ldquolevelrdquo But Services is ldquoVertical rdquo Service is adopted by the lower layer of
interface Functions is the internal activities
Services interface protocols and functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services to Protocols Relationship
The relationship between a service and a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layers of the ISOrsquos OSI reference model The layers of the OSI model on each node
communicate with each other
A layer in the OSI model represents a compon-ent of the total process of communicating T
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Actual communication passes down through the layers on the sending node and then up through the layers on the receiving node
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
X25The first three layers of the OSI model have been standardized and together are called the X25 standard for data transmission
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
GOSIP government open system Interconnetion Protocola subset of the OSI model that vendors must support if they want to sell network services or equipment to the US governmentGOSIP is neither a new architecture nor a New standardIt is a more precise specification of what parts of the OSI model the government will use
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipment
What are the Physical Layer components on my computer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
Vstandards define the connection of digital equipment to the PSTN`s analog linesV32 V33 V42 standard for the use of telephone transmission of data made a clear statement XstandardsDefine the connection of digital equipment to digital linesEG X25 X400 X500
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
37 ADVANTAGES AND DISADVANTAGES OF STANDARDS
Adv Standards allow products from multiple vendors to be connected to one another and to communicate
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
disadvanceThe standards-setting process is slowStandards tend to freeze technologyMultiple conflicting standardsThe standards-setting process can occur quickly(Writing standards is relatively easy ) when an architecture is in placeF
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
38 COMMUNICATIONS ARCHITECTURESISO and ITU-T developed OSI reference model in 1978OSI-RM Open Systems Interconnection reference modelThe standards development process took so long that the osi model never came into widespread useIt is the standard reference point by which data communications networks are described
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
39 THE ISO`S OSI REFERENCE MODEL391 Objective Provide a basis for interconnecting dissimilar systems for the purpose of information exchange Define communications rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI and most network architecture use a layered approach A layer in the OSI RM represents a component of the total process of communicating Each one layer requests services from the layer below it N layer Provide services to N+1 layer The same network any two-system must have the same level The actual physical communication completed only in the bottom layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
1) Layering forces the modularization of function Dealing with complex systemsThe output of laying definition process is standardseases maintenance updating of systemOne layer can be changed without affecting other layersDifferent implementations can be substituted relativelyTransparently
Why layering
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layer Layer requires reasonably sophisticated software and hardware at each end of the connection
前置处理机CCP
中央主机 中央主机中央主机
前置处理机
前置处理机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The philosopher-translator-Secretary architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
CN scientists
CN Translate
CNTelegrafisten
Telex machine
JP scientists
JP Translate
JPTelegrafisten
Telex machine
protocol
protocol
protocol
protocol
Scientific opinion
English
Letters
Telegraph code
Example Scientific exchange layered
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Architecture Layered principle Basic concept
Entity Can send or receive any information of hardware software process Peer layer Two different systems the same level Interface Interaction between the two neighboring layerSERVE for the upper classes a capacity to provide services through the interface Protocol Communication both in communication must comply with the rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
SYSA
SYSBentity Pee
r layerpeer
entity
server
Physical communication line
Layered network Architecture SYS
B
P3P2P1
2 1
3 2 1
Physical communication line
3
N+1 N N-1
N+1 N N-1Pn-1
Pn
Pn+1
SYSA
interfact
The way that the interaction between the layers actually takes place is that each one requests services from the layer above it
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services The way that the interaction between the layers actually takes place is that each one requests services from the layer above itEach layer provides services to the next higher layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Service PrimitivesPrimitiv
eMeaning
Request An Entity wants the service to do some work
Indication
An Entity is to be informed about an event
Response
An Entity wants to respond to an event
Confirm The Response to an eariler request has come back
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
服务用户( N+1 )
服务提供者( N )系统 A 服务用户
( N+1 )服务提供者
( N )系统 B
无需证实Request
Indication
RequestIndication
Response
Confirm
需证实PDU
Relations among Service Primitives
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
电话系统工作示例例如张三打电话请李四吃饭服务提供者为电话局 ① CONNECT request 张三拨李四的电话号码 ② CONNECT i ndi cati on 李四的电话振铃 ③ CONNECT response 李四摘机 ④ CONNECT confi rm 张三听到振铃停止知道有人应答 ⑤ DATA request 张三说话发出邀请 ⑥ DATA i ndi cati on 李四听到张三的邀请 ⑦ DATA request 李四说话接受邀请 ⑧ DATA i ndi cati on 张三听到李四的答复 ⑨ DI SCONNECT request 李四挂机 ⑩ DI SCONNECT i ndi cat i on 张三听到李四挂机也挂机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Protocols can provide a service for upper layer
Protocols is ldquolevelrdquo But Services is ldquoVertical rdquo Service is adopted by the lower layer of
interface Functions is the internal activities
Services interface protocols and functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services to Protocols Relationship
The relationship between a service and a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layers of the ISOrsquos OSI reference model The layers of the OSI model on each node
communicate with each other
A layer in the OSI model represents a compon-ent of the total process of communicating T
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Actual communication passes down through the layers on the sending node and then up through the layers on the receiving node
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
X25The first three layers of the OSI model have been standardized and together are called the X25 standard for data transmission
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
GOSIP government open system Interconnetion Protocola subset of the OSI model that vendors must support if they want to sell network services or equipment to the US governmentGOSIP is neither a new architecture nor a New standardIt is a more precise specification of what parts of the OSI model the government will use
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipment
What are the Physical Layer components on my computer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
37 ADVANTAGES AND DISADVANTAGES OF STANDARDS
Adv Standards allow products from multiple vendors to be connected to one another and to communicate
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
disadvanceThe standards-setting process is slowStandards tend to freeze technologyMultiple conflicting standardsThe standards-setting process can occur quickly(Writing standards is relatively easy ) when an architecture is in placeF
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
38 COMMUNICATIONS ARCHITECTURESISO and ITU-T developed OSI reference model in 1978OSI-RM Open Systems Interconnection reference modelThe standards development process took so long that the osi model never came into widespread useIt is the standard reference point by which data communications networks are described
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
39 THE ISO`S OSI REFERENCE MODEL391 Objective Provide a basis for interconnecting dissimilar systems for the purpose of information exchange Define communications rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI and most network architecture use a layered approach A layer in the OSI RM represents a component of the total process of communicating Each one layer requests services from the layer below it N layer Provide services to N+1 layer The same network any two-system must have the same level The actual physical communication completed only in the bottom layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
1) Layering forces the modularization of function Dealing with complex systemsThe output of laying definition process is standardseases maintenance updating of systemOne layer can be changed without affecting other layersDifferent implementations can be substituted relativelyTransparently
Why layering
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layer Layer requires reasonably sophisticated software and hardware at each end of the connection
前置处理机CCP
中央主机 中央主机中央主机
前置处理机
前置处理机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The philosopher-translator-Secretary architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
CN scientists
CN Translate
CNTelegrafisten
Telex machine
JP scientists
JP Translate
JPTelegrafisten
Telex machine
protocol
protocol
protocol
protocol
Scientific opinion
English
Letters
Telegraph code
Example Scientific exchange layered
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Architecture Layered principle Basic concept
Entity Can send or receive any information of hardware software process Peer layer Two different systems the same level Interface Interaction between the two neighboring layerSERVE for the upper classes a capacity to provide services through the interface Protocol Communication both in communication must comply with the rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
SYSA
SYSBentity Pee
r layerpeer
entity
server
Physical communication line
Layered network Architecture SYS
B
P3P2P1
2 1
3 2 1
Physical communication line
3
N+1 N N-1
N+1 N N-1Pn-1
Pn
Pn+1
SYSA
interfact
The way that the interaction between the layers actually takes place is that each one requests services from the layer above it
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services The way that the interaction between the layers actually takes place is that each one requests services from the layer above itEach layer provides services to the next higher layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Service PrimitivesPrimitiv
eMeaning
Request An Entity wants the service to do some work
Indication
An Entity is to be informed about an event
Response
An Entity wants to respond to an event
Confirm The Response to an eariler request has come back
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
服务用户( N+1 )
服务提供者( N )系统 A 服务用户
( N+1 )服务提供者
( N )系统 B
无需证实Request
Indication
RequestIndication
Response
Confirm
需证实PDU
Relations among Service Primitives
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
电话系统工作示例例如张三打电话请李四吃饭服务提供者为电话局 ① CONNECT request 张三拨李四的电话号码 ② CONNECT i ndi cati on 李四的电话振铃 ③ CONNECT response 李四摘机 ④ CONNECT confi rm 张三听到振铃停止知道有人应答 ⑤ DATA request 张三说话发出邀请 ⑥ DATA i ndi cati on 李四听到张三的邀请 ⑦ DATA request 李四说话接受邀请 ⑧ DATA i ndi cati on 张三听到李四的答复 ⑨ DI SCONNECT request 李四挂机 ⑩ DI SCONNECT i ndi cat i on 张三听到李四挂机也挂机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Protocols can provide a service for upper layer
Protocols is ldquolevelrdquo But Services is ldquoVertical rdquo Service is adopted by the lower layer of
interface Functions is the internal activities
Services interface protocols and functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services to Protocols Relationship
The relationship between a service and a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layers of the ISOrsquos OSI reference model The layers of the OSI model on each node
communicate with each other
A layer in the OSI model represents a compon-ent of the total process of communicating T
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Actual communication passes down through the layers on the sending node and then up through the layers on the receiving node
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
X25The first three layers of the OSI model have been standardized and together are called the X25 standard for data transmission
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
GOSIP government open system Interconnetion Protocola subset of the OSI model that vendors must support if they want to sell network services or equipment to the US governmentGOSIP is neither a new architecture nor a New standardIt is a more precise specification of what parts of the OSI model the government will use
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipment
What are the Physical Layer components on my computer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
disadvanceThe standards-setting process is slowStandards tend to freeze technologyMultiple conflicting standardsThe standards-setting process can occur quickly(Writing standards is relatively easy ) when an architecture is in placeF
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
38 COMMUNICATIONS ARCHITECTURESISO and ITU-T developed OSI reference model in 1978OSI-RM Open Systems Interconnection reference modelThe standards development process took so long that the osi model never came into widespread useIt is the standard reference point by which data communications networks are described
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
39 THE ISO`S OSI REFERENCE MODEL391 Objective Provide a basis for interconnecting dissimilar systems for the purpose of information exchange Define communications rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI and most network architecture use a layered approach A layer in the OSI RM represents a component of the total process of communicating Each one layer requests services from the layer below it N layer Provide services to N+1 layer The same network any two-system must have the same level The actual physical communication completed only in the bottom layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
1) Layering forces the modularization of function Dealing with complex systemsThe output of laying definition process is standardseases maintenance updating of systemOne layer can be changed without affecting other layersDifferent implementations can be substituted relativelyTransparently
Why layering
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layer Layer requires reasonably sophisticated software and hardware at each end of the connection
前置处理机CCP
中央主机 中央主机中央主机
前置处理机
前置处理机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The philosopher-translator-Secretary architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
CN scientists
CN Translate
CNTelegrafisten
Telex machine
JP scientists
JP Translate
JPTelegrafisten
Telex machine
protocol
protocol
protocol
protocol
Scientific opinion
English
Letters
Telegraph code
Example Scientific exchange layered
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Architecture Layered principle Basic concept
Entity Can send or receive any information of hardware software process Peer layer Two different systems the same level Interface Interaction between the two neighboring layerSERVE for the upper classes a capacity to provide services through the interface Protocol Communication both in communication must comply with the rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
SYSA
SYSBentity Pee
r layerpeer
entity
server
Physical communication line
Layered network Architecture SYS
B
P3P2P1
2 1
3 2 1
Physical communication line
3
N+1 N N-1
N+1 N N-1Pn-1
Pn
Pn+1
SYSA
interfact
The way that the interaction between the layers actually takes place is that each one requests services from the layer above it
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services The way that the interaction between the layers actually takes place is that each one requests services from the layer above itEach layer provides services to the next higher layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Service PrimitivesPrimitiv
eMeaning
Request An Entity wants the service to do some work
Indication
An Entity is to be informed about an event
Response
An Entity wants to respond to an event
Confirm The Response to an eariler request has come back
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
服务用户( N+1 )
服务提供者( N )系统 A 服务用户
( N+1 )服务提供者
( N )系统 B
无需证实Request
Indication
RequestIndication
Response
Confirm
需证实PDU
Relations among Service Primitives
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
电话系统工作示例例如张三打电话请李四吃饭服务提供者为电话局 ① CONNECT request 张三拨李四的电话号码 ② CONNECT i ndi cati on 李四的电话振铃 ③ CONNECT response 李四摘机 ④ CONNECT confi rm 张三听到振铃停止知道有人应答 ⑤ DATA request 张三说话发出邀请 ⑥ DATA i ndi cati on 李四听到张三的邀请 ⑦ DATA request 李四说话接受邀请 ⑧ DATA i ndi cati on 张三听到李四的答复 ⑨ DI SCONNECT request 李四挂机 ⑩ DI SCONNECT i ndi cat i on 张三听到李四挂机也挂机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Protocols can provide a service for upper layer
Protocols is ldquolevelrdquo But Services is ldquoVertical rdquo Service is adopted by the lower layer of
interface Functions is the internal activities
Services interface protocols and functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services to Protocols Relationship
The relationship between a service and a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layers of the ISOrsquos OSI reference model The layers of the OSI model on each node
communicate with each other
A layer in the OSI model represents a compon-ent of the total process of communicating T
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Actual communication passes down through the layers on the sending node and then up through the layers on the receiving node
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
X25The first three layers of the OSI model have been standardized and together are called the X25 standard for data transmission
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
GOSIP government open system Interconnetion Protocola subset of the OSI model that vendors must support if they want to sell network services or equipment to the US governmentGOSIP is neither a new architecture nor a New standardIt is a more precise specification of what parts of the OSI model the government will use
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipment
What are the Physical Layer components on my computer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
38 COMMUNICATIONS ARCHITECTURESISO and ITU-T developed OSI reference model in 1978OSI-RM Open Systems Interconnection reference modelThe standards development process took so long that the osi model never came into widespread useIt is the standard reference point by which data communications networks are described
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
39 THE ISO`S OSI REFERENCE MODEL391 Objective Provide a basis for interconnecting dissimilar systems for the purpose of information exchange Define communications rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI and most network architecture use a layered approach A layer in the OSI RM represents a component of the total process of communicating Each one layer requests services from the layer below it N layer Provide services to N+1 layer The same network any two-system must have the same level The actual physical communication completed only in the bottom layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
1) Layering forces the modularization of function Dealing with complex systemsThe output of laying definition process is standardseases maintenance updating of systemOne layer can be changed without affecting other layersDifferent implementations can be substituted relativelyTransparently
Why layering
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layer Layer requires reasonably sophisticated software and hardware at each end of the connection
前置处理机CCP
中央主机 中央主机中央主机
前置处理机
前置处理机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The philosopher-translator-Secretary architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
CN scientists
CN Translate
CNTelegrafisten
Telex machine
JP scientists
JP Translate
JPTelegrafisten
Telex machine
protocol
protocol
protocol
protocol
Scientific opinion
English
Letters
Telegraph code
Example Scientific exchange layered
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Architecture Layered principle Basic concept
Entity Can send or receive any information of hardware software process Peer layer Two different systems the same level Interface Interaction between the two neighboring layerSERVE for the upper classes a capacity to provide services through the interface Protocol Communication both in communication must comply with the rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
SYSA
SYSBentity Pee
r layerpeer
entity
server
Physical communication line
Layered network Architecture SYS
B
P3P2P1
2 1
3 2 1
Physical communication line
3
N+1 N N-1
N+1 N N-1Pn-1
Pn
Pn+1
SYSA
interfact
The way that the interaction between the layers actually takes place is that each one requests services from the layer above it
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services The way that the interaction between the layers actually takes place is that each one requests services from the layer above itEach layer provides services to the next higher layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Service PrimitivesPrimitiv
eMeaning
Request An Entity wants the service to do some work
Indication
An Entity is to be informed about an event
Response
An Entity wants to respond to an event
Confirm The Response to an eariler request has come back
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
服务用户( N+1 )
服务提供者( N )系统 A 服务用户
( N+1 )服务提供者
( N )系统 B
无需证实Request
Indication
RequestIndication
Response
Confirm
需证实PDU
Relations among Service Primitives
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
电话系统工作示例例如张三打电话请李四吃饭服务提供者为电话局 ① CONNECT request 张三拨李四的电话号码 ② CONNECT i ndi cati on 李四的电话振铃 ③ CONNECT response 李四摘机 ④ CONNECT confi rm 张三听到振铃停止知道有人应答 ⑤ DATA request 张三说话发出邀请 ⑥ DATA i ndi cati on 李四听到张三的邀请 ⑦ DATA request 李四说话接受邀请 ⑧ DATA i ndi cati on 张三听到李四的答复 ⑨ DI SCONNECT request 李四挂机 ⑩ DI SCONNECT i ndi cat i on 张三听到李四挂机也挂机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Protocols can provide a service for upper layer
Protocols is ldquolevelrdquo But Services is ldquoVertical rdquo Service is adopted by the lower layer of
interface Functions is the internal activities
Services interface protocols and functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services to Protocols Relationship
The relationship between a service and a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layers of the ISOrsquos OSI reference model The layers of the OSI model on each node
communicate with each other
A layer in the OSI model represents a compon-ent of the total process of communicating T
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Actual communication passes down through the layers on the sending node and then up through the layers on the receiving node
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
X25The first three layers of the OSI model have been standardized and together are called the X25 standard for data transmission
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
GOSIP government open system Interconnetion Protocola subset of the OSI model that vendors must support if they want to sell network services or equipment to the US governmentGOSIP is neither a new architecture nor a New standardIt is a more precise specification of what parts of the OSI model the government will use
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipment
What are the Physical Layer components on my computer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
39 THE ISO`S OSI REFERENCE MODEL391 Objective Provide a basis for interconnecting dissimilar systems for the purpose of information exchange Define communications rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI and most network architecture use a layered approach A layer in the OSI RM represents a component of the total process of communicating Each one layer requests services from the layer below it N layer Provide services to N+1 layer The same network any two-system must have the same level The actual physical communication completed only in the bottom layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
1) Layering forces the modularization of function Dealing with complex systemsThe output of laying definition process is standardseases maintenance updating of systemOne layer can be changed without affecting other layersDifferent implementations can be substituted relativelyTransparently
Why layering
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layer Layer requires reasonably sophisticated software and hardware at each end of the connection
前置处理机CCP
中央主机 中央主机中央主机
前置处理机
前置处理机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The philosopher-translator-Secretary architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
CN scientists
CN Translate
CNTelegrafisten
Telex machine
JP scientists
JP Translate
JPTelegrafisten
Telex machine
protocol
protocol
protocol
protocol
Scientific opinion
English
Letters
Telegraph code
Example Scientific exchange layered
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Architecture Layered principle Basic concept
Entity Can send or receive any information of hardware software process Peer layer Two different systems the same level Interface Interaction between the two neighboring layerSERVE for the upper classes a capacity to provide services through the interface Protocol Communication both in communication must comply with the rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
SYSA
SYSBentity Pee
r layerpeer
entity
server
Physical communication line
Layered network Architecture SYS
B
P3P2P1
2 1
3 2 1
Physical communication line
3
N+1 N N-1
N+1 N N-1Pn-1
Pn
Pn+1
SYSA
interfact
The way that the interaction between the layers actually takes place is that each one requests services from the layer above it
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services The way that the interaction between the layers actually takes place is that each one requests services from the layer above itEach layer provides services to the next higher layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Service PrimitivesPrimitiv
eMeaning
Request An Entity wants the service to do some work
Indication
An Entity is to be informed about an event
Response
An Entity wants to respond to an event
Confirm The Response to an eariler request has come back
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
服务用户( N+1 )
服务提供者( N )系统 A 服务用户
( N+1 )服务提供者
( N )系统 B
无需证实Request
Indication
RequestIndication
Response
Confirm
需证实PDU
Relations among Service Primitives
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
电话系统工作示例例如张三打电话请李四吃饭服务提供者为电话局 ① CONNECT request 张三拨李四的电话号码 ② CONNECT i ndi cati on 李四的电话振铃 ③ CONNECT response 李四摘机 ④ CONNECT confi rm 张三听到振铃停止知道有人应答 ⑤ DATA request 张三说话发出邀请 ⑥ DATA i ndi cati on 李四听到张三的邀请 ⑦ DATA request 李四说话接受邀请 ⑧ DATA i ndi cati on 张三听到李四的答复 ⑨ DI SCONNECT request 李四挂机 ⑩ DI SCONNECT i ndi cat i on 张三听到李四挂机也挂机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Protocols can provide a service for upper layer
Protocols is ldquolevelrdquo But Services is ldquoVertical rdquo Service is adopted by the lower layer of
interface Functions is the internal activities
Services interface protocols and functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services to Protocols Relationship
The relationship between a service and a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layers of the ISOrsquos OSI reference model The layers of the OSI model on each node
communicate with each other
A layer in the OSI model represents a compon-ent of the total process of communicating T
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Actual communication passes down through the layers on the sending node and then up through the layers on the receiving node
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
X25The first three layers of the OSI model have been standardized and together are called the X25 standard for data transmission
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
GOSIP government open system Interconnetion Protocola subset of the OSI model that vendors must support if they want to sell network services or equipment to the US governmentGOSIP is neither a new architecture nor a New standardIt is a more precise specification of what parts of the OSI model the government will use
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipment
What are the Physical Layer components on my computer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
OSI and most network architecture use a layered approach A layer in the OSI RM represents a component of the total process of communicating Each one layer requests services from the layer below it N layer Provide services to N+1 layer The same network any two-system must have the same level The actual physical communication completed only in the bottom layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
1) Layering forces the modularization of function Dealing with complex systemsThe output of laying definition process is standardseases maintenance updating of systemOne layer can be changed without affecting other layersDifferent implementations can be substituted relativelyTransparently
Why layering
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layer Layer requires reasonably sophisticated software and hardware at each end of the connection
前置处理机CCP
中央主机 中央主机中央主机
前置处理机
前置处理机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The philosopher-translator-Secretary architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
CN scientists
CN Translate
CNTelegrafisten
Telex machine
JP scientists
JP Translate
JPTelegrafisten
Telex machine
protocol
protocol
protocol
protocol
Scientific opinion
English
Letters
Telegraph code
Example Scientific exchange layered
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Architecture Layered principle Basic concept
Entity Can send or receive any information of hardware software process Peer layer Two different systems the same level Interface Interaction between the two neighboring layerSERVE for the upper classes a capacity to provide services through the interface Protocol Communication both in communication must comply with the rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
SYSA
SYSBentity Pee
r layerpeer
entity
server
Physical communication line
Layered network Architecture SYS
B
P3P2P1
2 1
3 2 1
Physical communication line
3
N+1 N N-1
N+1 N N-1Pn-1
Pn
Pn+1
SYSA
interfact
The way that the interaction between the layers actually takes place is that each one requests services from the layer above it
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services The way that the interaction between the layers actually takes place is that each one requests services from the layer above itEach layer provides services to the next higher layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Service PrimitivesPrimitiv
eMeaning
Request An Entity wants the service to do some work
Indication
An Entity is to be informed about an event
Response
An Entity wants to respond to an event
Confirm The Response to an eariler request has come back
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
服务用户( N+1 )
服务提供者( N )系统 A 服务用户
( N+1 )服务提供者
( N )系统 B
无需证实Request
Indication
RequestIndication
Response
Confirm
需证实PDU
Relations among Service Primitives
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
电话系统工作示例例如张三打电话请李四吃饭服务提供者为电话局 ① CONNECT request 张三拨李四的电话号码 ② CONNECT i ndi cati on 李四的电话振铃 ③ CONNECT response 李四摘机 ④ CONNECT confi rm 张三听到振铃停止知道有人应答 ⑤ DATA request 张三说话发出邀请 ⑥ DATA i ndi cati on 李四听到张三的邀请 ⑦ DATA request 李四说话接受邀请 ⑧ DATA i ndi cati on 张三听到李四的答复 ⑨ DI SCONNECT request 李四挂机 ⑩ DI SCONNECT i ndi cat i on 张三听到李四挂机也挂机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Protocols can provide a service for upper layer
Protocols is ldquolevelrdquo But Services is ldquoVertical rdquo Service is adopted by the lower layer of
interface Functions is the internal activities
Services interface protocols and functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services to Protocols Relationship
The relationship between a service and a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layers of the ISOrsquos OSI reference model The layers of the OSI model on each node
communicate with each other
A layer in the OSI model represents a compon-ent of the total process of communicating T
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Actual communication passes down through the layers on the sending node and then up through the layers on the receiving node
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
X25The first three layers of the OSI model have been standardized and together are called the X25 standard for data transmission
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
GOSIP government open system Interconnetion Protocola subset of the OSI model that vendors must support if they want to sell network services or equipment to the US governmentGOSIP is neither a new architecture nor a New standardIt is a more precise specification of what parts of the OSI model the government will use
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipment
What are the Physical Layer components on my computer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
1) Layering forces the modularization of function Dealing with complex systemsThe output of laying definition process is standardseases maintenance updating of systemOne layer can be changed without affecting other layersDifferent implementations can be substituted relativelyTransparently
Why layering
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layer Layer requires reasonably sophisticated software and hardware at each end of the connection
前置处理机CCP
中央主机 中央主机中央主机
前置处理机
前置处理机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The philosopher-translator-Secretary architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
CN scientists
CN Translate
CNTelegrafisten
Telex machine
JP scientists
JP Translate
JPTelegrafisten
Telex machine
protocol
protocol
protocol
protocol
Scientific opinion
English
Letters
Telegraph code
Example Scientific exchange layered
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Architecture Layered principle Basic concept
Entity Can send or receive any information of hardware software process Peer layer Two different systems the same level Interface Interaction between the two neighboring layerSERVE for the upper classes a capacity to provide services through the interface Protocol Communication both in communication must comply with the rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
SYSA
SYSBentity Pee
r layerpeer
entity
server
Physical communication line
Layered network Architecture SYS
B
P3P2P1
2 1
3 2 1
Physical communication line
3
N+1 N N-1
N+1 N N-1Pn-1
Pn
Pn+1
SYSA
interfact
The way that the interaction between the layers actually takes place is that each one requests services from the layer above it
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services The way that the interaction between the layers actually takes place is that each one requests services from the layer above itEach layer provides services to the next higher layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Service PrimitivesPrimitiv
eMeaning
Request An Entity wants the service to do some work
Indication
An Entity is to be informed about an event
Response
An Entity wants to respond to an event
Confirm The Response to an eariler request has come back
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
服务用户( N+1 )
服务提供者( N )系统 A 服务用户
( N+1 )服务提供者
( N )系统 B
无需证实Request
Indication
RequestIndication
Response
Confirm
需证实PDU
Relations among Service Primitives
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
电话系统工作示例例如张三打电话请李四吃饭服务提供者为电话局 ① CONNECT request 张三拨李四的电话号码 ② CONNECT i ndi cati on 李四的电话振铃 ③ CONNECT response 李四摘机 ④ CONNECT confi rm 张三听到振铃停止知道有人应答 ⑤ DATA request 张三说话发出邀请 ⑥ DATA i ndi cati on 李四听到张三的邀请 ⑦ DATA request 李四说话接受邀请 ⑧ DATA i ndi cati on 张三听到李四的答复 ⑨ DI SCONNECT request 李四挂机 ⑩ DI SCONNECT i ndi cat i on 张三听到李四挂机也挂机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Protocols can provide a service for upper layer
Protocols is ldquolevelrdquo But Services is ldquoVertical rdquo Service is adopted by the lower layer of
interface Functions is the internal activities
Services interface protocols and functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services to Protocols Relationship
The relationship between a service and a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layers of the ISOrsquos OSI reference model The layers of the OSI model on each node
communicate with each other
A layer in the OSI model represents a compon-ent of the total process of communicating T
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Actual communication passes down through the layers on the sending node and then up through the layers on the receiving node
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
X25The first three layers of the OSI model have been standardized and together are called the X25 standard for data transmission
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
GOSIP government open system Interconnetion Protocola subset of the OSI model that vendors must support if they want to sell network services or equipment to the US governmentGOSIP is neither a new architecture nor a New standardIt is a more precise specification of what parts of the OSI model the government will use
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipment
What are the Physical Layer components on my computer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
Layer Layer requires reasonably sophisticated software and hardware at each end of the connection
前置处理机CCP
中央主机 中央主机中央主机
前置处理机
前置处理机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The philosopher-translator-Secretary architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
CN scientists
CN Translate
CNTelegrafisten
Telex machine
JP scientists
JP Translate
JPTelegrafisten
Telex machine
protocol
protocol
protocol
protocol
Scientific opinion
English
Letters
Telegraph code
Example Scientific exchange layered
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Architecture Layered principle Basic concept
Entity Can send or receive any information of hardware software process Peer layer Two different systems the same level Interface Interaction between the two neighboring layerSERVE for the upper classes a capacity to provide services through the interface Protocol Communication both in communication must comply with the rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
SYSA
SYSBentity Pee
r layerpeer
entity
server
Physical communication line
Layered network Architecture SYS
B
P3P2P1
2 1
3 2 1
Physical communication line
3
N+1 N N-1
N+1 N N-1Pn-1
Pn
Pn+1
SYSA
interfact
The way that the interaction between the layers actually takes place is that each one requests services from the layer above it
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services The way that the interaction between the layers actually takes place is that each one requests services from the layer above itEach layer provides services to the next higher layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Service PrimitivesPrimitiv
eMeaning
Request An Entity wants the service to do some work
Indication
An Entity is to be informed about an event
Response
An Entity wants to respond to an event
Confirm The Response to an eariler request has come back
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
服务用户( N+1 )
服务提供者( N )系统 A 服务用户
( N+1 )服务提供者
( N )系统 B
无需证实Request
Indication
RequestIndication
Response
Confirm
需证实PDU
Relations among Service Primitives
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
电话系统工作示例例如张三打电话请李四吃饭服务提供者为电话局 ① CONNECT request 张三拨李四的电话号码 ② CONNECT i ndi cati on 李四的电话振铃 ③ CONNECT response 李四摘机 ④ CONNECT confi rm 张三听到振铃停止知道有人应答 ⑤ DATA request 张三说话发出邀请 ⑥ DATA i ndi cati on 李四听到张三的邀请 ⑦ DATA request 李四说话接受邀请 ⑧ DATA i ndi cati on 张三听到李四的答复 ⑨ DI SCONNECT request 李四挂机 ⑩ DI SCONNECT i ndi cat i on 张三听到李四挂机也挂机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Protocols can provide a service for upper layer
Protocols is ldquolevelrdquo But Services is ldquoVertical rdquo Service is adopted by the lower layer of
interface Functions is the internal activities
Services interface protocols and functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services to Protocols Relationship
The relationship between a service and a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layers of the ISOrsquos OSI reference model The layers of the OSI model on each node
communicate with each other
A layer in the OSI model represents a compon-ent of the total process of communicating T
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Actual communication passes down through the layers on the sending node and then up through the layers on the receiving node
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
X25The first three layers of the OSI model have been standardized and together are called the X25 standard for data transmission
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
GOSIP government open system Interconnetion Protocola subset of the OSI model that vendors must support if they want to sell network services or equipment to the US governmentGOSIP is neither a new architecture nor a New standardIt is a more precise specification of what parts of the OSI model the government will use
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipment
What are the Physical Layer components on my computer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
The philosopher-translator-Secretary architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
CN scientists
CN Translate
CNTelegrafisten
Telex machine
JP scientists
JP Translate
JPTelegrafisten
Telex machine
protocol
protocol
protocol
protocol
Scientific opinion
English
Letters
Telegraph code
Example Scientific exchange layered
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Architecture Layered principle Basic concept
Entity Can send or receive any information of hardware software process Peer layer Two different systems the same level Interface Interaction between the two neighboring layerSERVE for the upper classes a capacity to provide services through the interface Protocol Communication both in communication must comply with the rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
SYSA
SYSBentity Pee
r layerpeer
entity
server
Physical communication line
Layered network Architecture SYS
B
P3P2P1
2 1
3 2 1
Physical communication line
3
N+1 N N-1
N+1 N N-1Pn-1
Pn
Pn+1
SYSA
interfact
The way that the interaction between the layers actually takes place is that each one requests services from the layer above it
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services The way that the interaction between the layers actually takes place is that each one requests services from the layer above itEach layer provides services to the next higher layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Service PrimitivesPrimitiv
eMeaning
Request An Entity wants the service to do some work
Indication
An Entity is to be informed about an event
Response
An Entity wants to respond to an event
Confirm The Response to an eariler request has come back
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
服务用户( N+1 )
服务提供者( N )系统 A 服务用户
( N+1 )服务提供者
( N )系统 B
无需证实Request
Indication
RequestIndication
Response
Confirm
需证实PDU
Relations among Service Primitives
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
电话系统工作示例例如张三打电话请李四吃饭服务提供者为电话局 ① CONNECT request 张三拨李四的电话号码 ② CONNECT i ndi cati on 李四的电话振铃 ③ CONNECT response 李四摘机 ④ CONNECT confi rm 张三听到振铃停止知道有人应答 ⑤ DATA request 张三说话发出邀请 ⑥ DATA i ndi cati on 李四听到张三的邀请 ⑦ DATA request 李四说话接受邀请 ⑧ DATA i ndi cati on 张三听到李四的答复 ⑨ DI SCONNECT request 李四挂机 ⑩ DI SCONNECT i ndi cat i on 张三听到李四挂机也挂机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Protocols can provide a service for upper layer
Protocols is ldquolevelrdquo But Services is ldquoVertical rdquo Service is adopted by the lower layer of
interface Functions is the internal activities
Services interface protocols and functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services to Protocols Relationship
The relationship between a service and a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layers of the ISOrsquos OSI reference model The layers of the OSI model on each node
communicate with each other
A layer in the OSI model represents a compon-ent of the total process of communicating T
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Actual communication passes down through the layers on the sending node and then up through the layers on the receiving node
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
X25The first three layers of the OSI model have been standardized and together are called the X25 standard for data transmission
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
GOSIP government open system Interconnetion Protocola subset of the OSI model that vendors must support if they want to sell network services or equipment to the US governmentGOSIP is neither a new architecture nor a New standardIt is a more precise specification of what parts of the OSI model the government will use
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipment
What are the Physical Layer components on my computer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
CN scientists
CN Translate
CNTelegrafisten
Telex machine
JP scientists
JP Translate
JPTelegrafisten
Telex machine
protocol
protocol
protocol
protocol
Scientific opinion
English
Letters
Telegraph code
Example Scientific exchange layered
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Architecture Layered principle Basic concept
Entity Can send or receive any information of hardware software process Peer layer Two different systems the same level Interface Interaction between the two neighboring layerSERVE for the upper classes a capacity to provide services through the interface Protocol Communication both in communication must comply with the rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
SYSA
SYSBentity Pee
r layerpeer
entity
server
Physical communication line
Layered network Architecture SYS
B
P3P2P1
2 1
3 2 1
Physical communication line
3
N+1 N N-1
N+1 N N-1Pn-1
Pn
Pn+1
SYSA
interfact
The way that the interaction between the layers actually takes place is that each one requests services from the layer above it
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services The way that the interaction between the layers actually takes place is that each one requests services from the layer above itEach layer provides services to the next higher layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Service PrimitivesPrimitiv
eMeaning
Request An Entity wants the service to do some work
Indication
An Entity is to be informed about an event
Response
An Entity wants to respond to an event
Confirm The Response to an eariler request has come back
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
服务用户( N+1 )
服务提供者( N )系统 A 服务用户
( N+1 )服务提供者
( N )系统 B
无需证实Request
Indication
RequestIndication
Response
Confirm
需证实PDU
Relations among Service Primitives
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
电话系统工作示例例如张三打电话请李四吃饭服务提供者为电话局 ① CONNECT request 张三拨李四的电话号码 ② CONNECT i ndi cati on 李四的电话振铃 ③ CONNECT response 李四摘机 ④ CONNECT confi rm 张三听到振铃停止知道有人应答 ⑤ DATA request 张三说话发出邀请 ⑥ DATA i ndi cati on 李四听到张三的邀请 ⑦ DATA request 李四说话接受邀请 ⑧ DATA i ndi cati on 张三听到李四的答复 ⑨ DI SCONNECT request 李四挂机 ⑩ DI SCONNECT i ndi cat i on 张三听到李四挂机也挂机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Protocols can provide a service for upper layer
Protocols is ldquolevelrdquo But Services is ldquoVertical rdquo Service is adopted by the lower layer of
interface Functions is the internal activities
Services interface protocols and functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services to Protocols Relationship
The relationship between a service and a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layers of the ISOrsquos OSI reference model The layers of the OSI model on each node
communicate with each other
A layer in the OSI model represents a compon-ent of the total process of communicating T
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Actual communication passes down through the layers on the sending node and then up through the layers on the receiving node
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
X25The first three layers of the OSI model have been standardized and together are called the X25 standard for data transmission
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
GOSIP government open system Interconnetion Protocola subset of the OSI model that vendors must support if they want to sell network services or equipment to the US governmentGOSIP is neither a new architecture nor a New standardIt is a more precise specification of what parts of the OSI model the government will use
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipment
What are the Physical Layer components on my computer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
Network Architecture Layered principle Basic concept
Entity Can send or receive any information of hardware software process Peer layer Two different systems the same level Interface Interaction between the two neighboring layerSERVE for the upper classes a capacity to provide services through the interface Protocol Communication both in communication must comply with the rules
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
SYSA
SYSBentity Pee
r layerpeer
entity
server
Physical communication line
Layered network Architecture SYS
B
P3P2P1
2 1
3 2 1
Physical communication line
3
N+1 N N-1
N+1 N N-1Pn-1
Pn
Pn+1
SYSA
interfact
The way that the interaction between the layers actually takes place is that each one requests services from the layer above it
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services The way that the interaction between the layers actually takes place is that each one requests services from the layer above itEach layer provides services to the next higher layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Service PrimitivesPrimitiv
eMeaning
Request An Entity wants the service to do some work
Indication
An Entity is to be informed about an event
Response
An Entity wants to respond to an event
Confirm The Response to an eariler request has come back
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
服务用户( N+1 )
服务提供者( N )系统 A 服务用户
( N+1 )服务提供者
( N )系统 B
无需证实Request
Indication
RequestIndication
Response
Confirm
需证实PDU
Relations among Service Primitives
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
电话系统工作示例例如张三打电话请李四吃饭服务提供者为电话局 ① CONNECT request 张三拨李四的电话号码 ② CONNECT i ndi cati on 李四的电话振铃 ③ CONNECT response 李四摘机 ④ CONNECT confi rm 张三听到振铃停止知道有人应答 ⑤ DATA request 张三说话发出邀请 ⑥ DATA i ndi cati on 李四听到张三的邀请 ⑦ DATA request 李四说话接受邀请 ⑧ DATA i ndi cati on 张三听到李四的答复 ⑨ DI SCONNECT request 李四挂机 ⑩ DI SCONNECT i ndi cat i on 张三听到李四挂机也挂机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Protocols can provide a service for upper layer
Protocols is ldquolevelrdquo But Services is ldquoVertical rdquo Service is adopted by the lower layer of
interface Functions is the internal activities
Services interface protocols and functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services to Protocols Relationship
The relationship between a service and a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layers of the ISOrsquos OSI reference model The layers of the OSI model on each node
communicate with each other
A layer in the OSI model represents a compon-ent of the total process of communicating T
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Actual communication passes down through the layers on the sending node and then up through the layers on the receiving node
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
X25The first three layers of the OSI model have been standardized and together are called the X25 standard for data transmission
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
GOSIP government open system Interconnetion Protocola subset of the OSI model that vendors must support if they want to sell network services or equipment to the US governmentGOSIP is neither a new architecture nor a New standardIt is a more precise specification of what parts of the OSI model the government will use
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipment
What are the Physical Layer components on my computer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
SYSA
SYSBentity Pee
r layerpeer
entity
server
Physical communication line
Layered network Architecture SYS
B
P3P2P1
2 1
3 2 1
Physical communication line
3
N+1 N N-1
N+1 N N-1Pn-1
Pn
Pn+1
SYSA
interfact
The way that the interaction between the layers actually takes place is that each one requests services from the layer above it
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services The way that the interaction between the layers actually takes place is that each one requests services from the layer above itEach layer provides services to the next higher layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Service PrimitivesPrimitiv
eMeaning
Request An Entity wants the service to do some work
Indication
An Entity is to be informed about an event
Response
An Entity wants to respond to an event
Confirm The Response to an eariler request has come back
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
服务用户( N+1 )
服务提供者( N )系统 A 服务用户
( N+1 )服务提供者
( N )系统 B
无需证实Request
Indication
RequestIndication
Response
Confirm
需证实PDU
Relations among Service Primitives
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
电话系统工作示例例如张三打电话请李四吃饭服务提供者为电话局 ① CONNECT request 张三拨李四的电话号码 ② CONNECT i ndi cati on 李四的电话振铃 ③ CONNECT response 李四摘机 ④ CONNECT confi rm 张三听到振铃停止知道有人应答 ⑤ DATA request 张三说话发出邀请 ⑥ DATA i ndi cati on 李四听到张三的邀请 ⑦ DATA request 李四说话接受邀请 ⑧ DATA i ndi cati on 张三听到李四的答复 ⑨ DI SCONNECT request 李四挂机 ⑩ DI SCONNECT i ndi cat i on 张三听到李四挂机也挂机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Protocols can provide a service for upper layer
Protocols is ldquolevelrdquo But Services is ldquoVertical rdquo Service is adopted by the lower layer of
interface Functions is the internal activities
Services interface protocols and functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services to Protocols Relationship
The relationship between a service and a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layers of the ISOrsquos OSI reference model The layers of the OSI model on each node
communicate with each other
A layer in the OSI model represents a compon-ent of the total process of communicating T
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Actual communication passes down through the layers on the sending node and then up through the layers on the receiving node
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
X25The first three layers of the OSI model have been standardized and together are called the X25 standard for data transmission
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
GOSIP government open system Interconnetion Protocola subset of the OSI model that vendors must support if they want to sell network services or equipment to the US governmentGOSIP is neither a new architecture nor a New standardIt is a more precise specification of what parts of the OSI model the government will use
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipment
What are the Physical Layer components on my computer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
Services The way that the interaction between the layers actually takes place is that each one requests services from the layer above itEach layer provides services to the next higher layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Service PrimitivesPrimitiv
eMeaning
Request An Entity wants the service to do some work
Indication
An Entity is to be informed about an event
Response
An Entity wants to respond to an event
Confirm The Response to an eariler request has come back
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
服务用户( N+1 )
服务提供者( N )系统 A 服务用户
( N+1 )服务提供者
( N )系统 B
无需证实Request
Indication
RequestIndication
Response
Confirm
需证实PDU
Relations among Service Primitives
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
电话系统工作示例例如张三打电话请李四吃饭服务提供者为电话局 ① CONNECT request 张三拨李四的电话号码 ② CONNECT i ndi cati on 李四的电话振铃 ③ CONNECT response 李四摘机 ④ CONNECT confi rm 张三听到振铃停止知道有人应答 ⑤ DATA request 张三说话发出邀请 ⑥ DATA i ndi cati on 李四听到张三的邀请 ⑦ DATA request 李四说话接受邀请 ⑧ DATA i ndi cati on 张三听到李四的答复 ⑨ DI SCONNECT request 李四挂机 ⑩ DI SCONNECT i ndi cat i on 张三听到李四挂机也挂机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Protocols can provide a service for upper layer
Protocols is ldquolevelrdquo But Services is ldquoVertical rdquo Service is adopted by the lower layer of
interface Functions is the internal activities
Services interface protocols and functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services to Protocols Relationship
The relationship between a service and a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layers of the ISOrsquos OSI reference model The layers of the OSI model on each node
communicate with each other
A layer in the OSI model represents a compon-ent of the total process of communicating T
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Actual communication passes down through the layers on the sending node and then up through the layers on the receiving node
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
X25The first three layers of the OSI model have been standardized and together are called the X25 standard for data transmission
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
GOSIP government open system Interconnetion Protocola subset of the OSI model that vendors must support if they want to sell network services or equipment to the US governmentGOSIP is neither a new architecture nor a New standardIt is a more precise specification of what parts of the OSI model the government will use
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipment
What are the Physical Layer components on my computer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
Service PrimitivesPrimitiv
eMeaning
Request An Entity wants the service to do some work
Indication
An Entity is to be informed about an event
Response
An Entity wants to respond to an event
Confirm The Response to an eariler request has come back
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
服务用户( N+1 )
服务提供者( N )系统 A 服务用户
( N+1 )服务提供者
( N )系统 B
无需证实Request
Indication
RequestIndication
Response
Confirm
需证实PDU
Relations among Service Primitives
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
电话系统工作示例例如张三打电话请李四吃饭服务提供者为电话局 ① CONNECT request 张三拨李四的电话号码 ② CONNECT i ndi cati on 李四的电话振铃 ③ CONNECT response 李四摘机 ④ CONNECT confi rm 张三听到振铃停止知道有人应答 ⑤ DATA request 张三说话发出邀请 ⑥ DATA i ndi cati on 李四听到张三的邀请 ⑦ DATA request 李四说话接受邀请 ⑧ DATA i ndi cati on 张三听到李四的答复 ⑨ DI SCONNECT request 李四挂机 ⑩ DI SCONNECT i ndi cat i on 张三听到李四挂机也挂机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Protocols can provide a service for upper layer
Protocols is ldquolevelrdquo But Services is ldquoVertical rdquo Service is adopted by the lower layer of
interface Functions is the internal activities
Services interface protocols and functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services to Protocols Relationship
The relationship between a service and a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layers of the ISOrsquos OSI reference model The layers of the OSI model on each node
communicate with each other
A layer in the OSI model represents a compon-ent of the total process of communicating T
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Actual communication passes down through the layers on the sending node and then up through the layers on the receiving node
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
X25The first three layers of the OSI model have been standardized and together are called the X25 standard for data transmission
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
GOSIP government open system Interconnetion Protocola subset of the OSI model that vendors must support if they want to sell network services or equipment to the US governmentGOSIP is neither a new architecture nor a New standardIt is a more precise specification of what parts of the OSI model the government will use
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipment
What are the Physical Layer components on my computer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
服务用户( N+1 )
服务提供者( N )系统 A 服务用户
( N+1 )服务提供者
( N )系统 B
无需证实Request
Indication
RequestIndication
Response
Confirm
需证实PDU
Relations among Service Primitives
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
电话系统工作示例例如张三打电话请李四吃饭服务提供者为电话局 ① CONNECT request 张三拨李四的电话号码 ② CONNECT i ndi cati on 李四的电话振铃 ③ CONNECT response 李四摘机 ④ CONNECT confi rm 张三听到振铃停止知道有人应答 ⑤ DATA request 张三说话发出邀请 ⑥ DATA i ndi cati on 李四听到张三的邀请 ⑦ DATA request 李四说话接受邀请 ⑧ DATA i ndi cati on 张三听到李四的答复 ⑨ DI SCONNECT request 李四挂机 ⑩ DI SCONNECT i ndi cat i on 张三听到李四挂机也挂机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Protocols can provide a service for upper layer
Protocols is ldquolevelrdquo But Services is ldquoVertical rdquo Service is adopted by the lower layer of
interface Functions is the internal activities
Services interface protocols and functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services to Protocols Relationship
The relationship between a service and a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layers of the ISOrsquos OSI reference model The layers of the OSI model on each node
communicate with each other
A layer in the OSI model represents a compon-ent of the total process of communicating T
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Actual communication passes down through the layers on the sending node and then up through the layers on the receiving node
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
X25The first three layers of the OSI model have been standardized and together are called the X25 standard for data transmission
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
GOSIP government open system Interconnetion Protocola subset of the OSI model that vendors must support if they want to sell network services or equipment to the US governmentGOSIP is neither a new architecture nor a New standardIt is a more precise specification of what parts of the OSI model the government will use
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipment
What are the Physical Layer components on my computer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
电话系统工作示例例如张三打电话请李四吃饭服务提供者为电话局 ① CONNECT request 张三拨李四的电话号码 ② CONNECT i ndi cati on 李四的电话振铃 ③ CONNECT response 李四摘机 ④ CONNECT confi rm 张三听到振铃停止知道有人应答 ⑤ DATA request 张三说话发出邀请 ⑥ DATA i ndi cati on 李四听到张三的邀请 ⑦ DATA request 李四说话接受邀请 ⑧ DATA i ndi cati on 张三听到李四的答复 ⑨ DI SCONNECT request 李四挂机 ⑩ DI SCONNECT i ndi cat i on 张三听到李四挂机也挂机
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Protocols can provide a service for upper layer
Protocols is ldquolevelrdquo But Services is ldquoVertical rdquo Service is adopted by the lower layer of
interface Functions is the internal activities
Services interface protocols and functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services to Protocols Relationship
The relationship between a service and a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layers of the ISOrsquos OSI reference model The layers of the OSI model on each node
communicate with each other
A layer in the OSI model represents a compon-ent of the total process of communicating T
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Actual communication passes down through the layers on the sending node and then up through the layers on the receiving node
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
X25The first three layers of the OSI model have been standardized and together are called the X25 standard for data transmission
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
GOSIP government open system Interconnetion Protocola subset of the OSI model that vendors must support if they want to sell network services or equipment to the US governmentGOSIP is neither a new architecture nor a New standardIt is a more precise specification of what parts of the OSI model the government will use
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipment
What are the Physical Layer components on my computer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
Protocols can provide a service for upper layer
Protocols is ldquolevelrdquo But Services is ldquoVertical rdquo Service is adopted by the lower layer of
interface Functions is the internal activities
Services interface protocols and functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Services to Protocols Relationship
The relationship between a service and a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layers of the ISOrsquos OSI reference model The layers of the OSI model on each node
communicate with each other
A layer in the OSI model represents a compon-ent of the total process of communicating T
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Actual communication passes down through the layers on the sending node and then up through the layers on the receiving node
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
X25The first three layers of the OSI model have been standardized and together are called the X25 standard for data transmission
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
GOSIP government open system Interconnetion Protocola subset of the OSI model that vendors must support if they want to sell network services or equipment to the US governmentGOSIP is neither a new architecture nor a New standardIt is a more precise specification of what parts of the OSI model the government will use
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipment
What are the Physical Layer components on my computer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
Services to Protocols Relationship
The relationship between a service and a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Layers of the ISOrsquos OSI reference model The layers of the OSI model on each node
communicate with each other
A layer in the OSI model represents a compon-ent of the total process of communicating T
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Actual communication passes down through the layers on the sending node and then up through the layers on the receiving node
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
X25The first three layers of the OSI model have been standardized and together are called the X25 standard for data transmission
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
GOSIP government open system Interconnetion Protocola subset of the OSI model that vendors must support if they want to sell network services or equipment to the US governmentGOSIP is neither a new architecture nor a New standardIt is a more precise specification of what parts of the OSI model the government will use
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipment
What are the Physical Layer components on my computer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
Layers of the ISOrsquos OSI reference model The layers of the OSI model on each node
communicate with each other
A layer in the OSI model represents a compon-ent of the total process of communicating T
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Actual communication passes down through the layers on the sending node and then up through the layers on the receiving node
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
X25The first three layers of the OSI model have been standardized and together are called the X25 standard for data transmission
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
GOSIP government open system Interconnetion Protocola subset of the OSI model that vendors must support if they want to sell network services or equipment to the US governmentGOSIP is neither a new architecture nor a New standardIt is a more precise specification of what parts of the OSI model the government will use
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipment
What are the Physical Layer components on my computer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
Actual communication passes down through the layers on the sending node and then up through the layers on the receiving node
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
X25The first three layers of the OSI model have been standardized and together are called the X25 standard for data transmission
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
GOSIP government open system Interconnetion Protocola subset of the OSI model that vendors must support if they want to sell network services or equipment to the US governmentGOSIP is neither a new architecture nor a New standardIt is a more precise specification of what parts of the OSI model the government will use
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipment
What are the Physical Layer components on my computer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
X25The first three layers of the OSI model have been standardized and together are called the X25 standard for data transmission
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
GOSIP government open system Interconnetion Protocola subset of the OSI model that vendors must support if they want to sell network services or equipment to the US governmentGOSIP is neither a new architecture nor a New standardIt is a more precise specification of what parts of the OSI model the government will use
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipment
What are the Physical Layer components on my computer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
GOSIP government open system Interconnetion Protocola subset of the OSI model that vendors must support if they want to sell network services or equipment to the US governmentGOSIP is neither a new architecture nor a New standardIt is a more precise specification of what parts of the OSI model the government will use
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipment
What are the Physical Layer components on my computer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
392The Function Of Each Layer LAYER 1 THE PHYSICAL LINK LAYER
It specifies the electrical characteristics between the communications line and the terminal or computer CablingInterconnect methods (topology devices)Data encoding (bits to waves)Electrical properties
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipment
What are the Physical Layer components on my computer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
Typical equipment
What are the Physical Layer components on my computer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
Physical Layer
This is the only layer at which actual bits passThe only layer that is implemented strictly in hardwareThe only layer that actually communicates across the transmission line to the other nodeLayer1 only knows about a strem of bitsData transmission unit is bits Transmission media does not belong to the physical layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
LAYER2 THE DATA LINK LAYER
FunctionFraming (成帧)Line disciplineFlow controlError control
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
Data link layer It is responsible for establishing a link between two points on a network and ensuring that data are successfully transferred between the two points Divide the data into smaller units for transmission( FRAME )Detecting transmission errors and correcting errors
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
Network Interface Card Bridge
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
LAYER 3 THE NETWORK LAYER
It is responsible for routing a message all the way through the network from the transmitter to the receiver is the network layer
Transmission units is package
Point-to-point
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
LAYER4 THE TRANSPORT LAYERIdentifies actual address but donrsquot know routeDetermine if the entire message was received correctlyis responsible for end-to-end (source to destination) packet delivery Taskhellip hellip两端点间可靠的透明数据传输(应用进程间的逻辑通信)
networkend-to-end
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
Also calculates a check sum for the entire messagewhich is recalculated by layer4 at The receiving end and compared
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
LAYER 5 THE SEEION LAYER
It is responsible for establishing the communications rules between specific machines or applications provides the mechanism for opening closing and managing a session between end-user application processes
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
Session Layer Dialog
Pacing the rate of transmission so data are not sent faster than the receiver can handle it
Certain accounting function
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
LAYER 6 THE PRESENTATION LAYER
Provides common data formatting between communicating devicesComponents make sure the receiving station can read the transferred data
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
Direct and Indirect Methods of Translation Concept of Encryption and Decryption
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
Data Compression Methods Run-Length Encoding
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
LAYER 7 THE APPLICATION LAYER It is ldquowhererdquo the user works at a terminal with computer softwareIt provides a set of interfaces for applications to obtain access to networked services as well as access to the kinds of network services that support applications directlyOSI - FTAMVTMHSDSCMIP
TCPIP - FTPSMTPTELNETDNSSNMPAlthough the notion of an application process is common to both their approaches to constructing application entities is different
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理) NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Five common application of OSI
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
Typical equipmentGateway proxy firewall
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
Summary of Layer Functions
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
OSI 模型是协助网络检修人员识别网络问题一种理想的框架
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
310 TCPIP ARCHITECTURETCPIP Transmission Control ProtocolInternet Protocol
The official TCPIP model is now maintained by the IETF(ITU-T) Because progress on setting standards for the OSI model was slow DARPA developed a set of protocols called TCPIPTCPIP has become the de facto standard protocol for internets
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
The acronym of the US governments version of the open system interconnection protocol is InternetIn 1969ARPA funded and created the ldquoARPAnetrdquo network
In 1975Convert from experimental to operational networkTCPIP begun to be developed
In 1983The TCPIP is adopted as Military StandardsARPnet MILNET + ARPnet = Internet
In 1985The NSF created the NSFnet to connect to InternetNSF = National Science Foundation
In 1990ARPA passed out of existence and in 1995 the NSFnet became the primary Internet backbone network
TCPIP and the Internet
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
TCPIP 4-layer or 5-layer
ApplicationLayer
TransportLayer
InternetLayer
Network Interface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
Physical
CISCO and IBM use the four-layer modelWe use the five-layer model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
A comparison of the layers of the OSI reference model and the implementation of TCPIP
Network Interface
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
PROTOCOLSEach layer has several protocolsA layer define a data communication function that may be performed by certain protocolsA protocol provides a service suitable to the function of that layer
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
TCPIP and the OSI Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
Application layerProvide services that can be used by other applicationsIncorporate the functions of top 3 OSI layersContains the programming required to support the user`s applicationDifferent module are required for each application
OSI application TCPIP application
CMIP (通用管理信息协议) SNMP NETVIEW
DS (目录服务) NDS NTDS
FTAM (文件的传输存取和管理)
NETWARE NFS
MHS (报文处理系统)VTP (虚拟终端协议) TELNET
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
Transport layerApplication layer directly run over the transport layer corresponding to OSI transport layerTwo kinds of services TCP amp UDP
TCPmdashTransmission Control Protocol reliable connect-oriented transfer of a byte stream
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
UDPmdash(User Datagram Protocol)best-effort connectionless transfer of
individual messagesThe advantage of a connectionless protocol is that there is no setup time at the beginning of the communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducnFigure 211
Internet layer
1 Transfer of information across networks through gatewaysrouters2 Global unique IP address and IP packets
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network Interface
Network 1 Network 2
RouterGateway
The internet layer of TCPIP routes data between networks when necessary using the IP protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducnFigure 211
Network interface layer
1 Corresponding to part of OSI network layer and data link layer2 Different network interfaces X25 ATM frame relay Ethernet etc
IP packet
Machine A Machine B
ApplicationTransport
InternetNetwork Interface
ApplicationTransportInternet
Network InterfaceInternet
Network InterfaceS
Network 1 Network 2
RouterGateway
Packetof network1
Packetof network1
IP packet
IP packet
Packetof network2
IP packet
Packetof network2
Handles the connection between the end system and the network to which it is attached
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
Some Protocols in TCPIP Suite
Internet
Transport
App
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
A Critique of the TCPIP Reference ModelProblemsService interface and protocol not distinguishedNot a general modeldoes not require strict layering
Applicationayer
TransportLayer
InternetLayer
NetworkInterface
ApplicationLayer
TransportLayer
InternetLayer
NetworkInterface
(a) (b)
TCPIP network architecture
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
311 Architecture of the Internet
The Internet is a network of networks Guide Informal architectural it was not formalized until later
The architects of the Internet dont insist on documenting every detail of Internet operation before implementation work began
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
The four initial requirements confronting the Internetrsquos architects were Multiplexing Survivability service generalitysupporting diverse network technologies The primary initial requirement that the architects of the Internet addressed were diverse network technologies
Design Guidelines
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
Designer
security
What entities Naming addressing routing
ModularizedResources are allocated
Concerned with
It wasn`t until 1991 that the Word Wide Web was introducee and Internet began to move from being an academic and military tool to being the tool it now os for researchsalesand communication
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
312 MANUFACTURERS`ARCHITECTURES Before OSI RM IBM SNA DEC DNA Burroughs BNSIt is a proprietary architectureManufacturers that developed network architectures were primarily interested in developing proprietary architectures on which to base their future products
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
IBM SNA
Because of customer and market pressuresthe situation changed and computer manufacturers became fully supportive of the international communications standards
DEC DNAIBM SNA
SNA DNA ARCHITECTURES
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
OTHER ARCHITECTUREThe ATM Reference ModelNovell NetWare RMWindows NT RMA Proposed Reference Model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
The ATM reference model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
NOVELL NETWARE RM
各种应用服务
应用层
表示层
会话层
传输层
网络层
数据链路层
物理层
SPX
IPX
网络接口卡与 网卡驱动程序
OSI Novell NetWare
IPXSPX ( internetwork packet exchange sequences packet exchange)
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
Windows NT 网络体系与模型
传输协议
客户机层
7
6
1
2
3
45
应用层
表示层
传输层
会话层
数据链路层
物理层
网络层
OSI模型
以太网令牌环或其他
环境子系统
IO文件 命名管道邮mailslots件槽
NDIS30接口NDIS环境和驱动
NetBEUI TCPIP
重定向器
TDI服务器
服务器
协议NDIS
协议
SMB
Windows NT RM
NetBEUI NWLink
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
A Proposed Reference Model
应 用 层
传 输 层
网 络 层
数据链路层
物 理 层
Andrew STanenbaum5 layers of RM No presentation layer session
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
3-13 A CAVEATIt is important to understand that writing the specifications for communications architectures and the related standards is difficult workAs actual communications systems have been implemented over the years most have not strictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
3-14 ADVS AND DISADVS OF LAYERED ARCHITECTURES
1Layering forces the modularization of function2 Good flexibility 3 Easy to achieve and maintain 4 Scalability 5Standardization A protocol stack is software that implements the layers of a protocol
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn
OSI vs TCPIP Reference Models
OSI introduced concept of services interface protocols These were force-fitted to TCP later In OSI reference model was done before protocols In TCP protocols were done before the model OSI Standardize first build later TCP Build first standardize later As actual communications systems have been implemented over the years most have notstrictly followed the OSI model
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation
课后习题
A X25 standard for data transmission
1 The first three layers of the OSI model have been standardized and together are called the ( ) A
B V standard
D Consolidated Transmission Protocol
C consolidated transmission standard
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation
课后习题
D the V and X standards
2 The ITU-T has created two sets of standards for the electrical connection of terminals to communications networks They are called ( ) D
A the ISO and OSI standards
B the TCP and IP standardsC the PC and modem standards
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation
课后习题
C is a proprietary architecture
3 IBMrsquos SNA ( ) C
A was never widely implemented
B is a data link protocol
D was an advanced mainframe computer for its time
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation
课后习题
C a set of principles used as the basis for the design and implementation of a communications network
4 A network architecture is ( ) C
A the plan for the Internetrsquos evolution
B a description of how a network is to be implemented
D None of the above
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation
课后习题
D All of the above
5 The Interne ( ) D
A is implemented using the TCPIP protocol
B has the attribute of service generality
C allows for diverse network technologies
AnswerRedo Next
times
times
times
radic
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation
课后习题1 A set of principles used as the basis for the design and
implementation of a communications network is called a ________________network architecture
Answer
Exercises
2The_____________ reference model is the standard reference point by which data communications networks are described and measured
OSI
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation
课后习题3Two telephone callers may be connected but they will not be able to ___________ and exchange information if they speak different languages
communicate
Answer
Exercises
4The________ _________ layer specifies the electrical characteristics between the communications line and the terminal or computer system
Physical link
Answer
Chapter 3 Network Architetures and Standarts
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation
课后习题5When data are received the OSI presentation layer is responsible for ___________the data to meet the needs of the application layer
formatting
Answer
Exercises
Chapter 3 Network Architetures and Standarts
Network Management and Operation wwwgxmueducn
Network Management and Operation wwwgxmueducn