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1
Introduction
Chapter 1
2
10 Technology Revolution
bull 18th Century Mechanical systems
bull 19th Century Steam Engine
bull 20th Century Information
- gathering
- distribution
- processing
- creating
3
A set of communication elements connected by communication links
Communication elements Computers printers mobile phones hellip Routers switches
Communication links optic fiber coaxial cable twisted pair wireless (radio microwave satellite)
Topologies Ring Star Bus Tree Mesh
What is a Computer Network
local ISP
companynetwork
regional ISP
router workstation
servermobile
4
A softwarehardware infrastructure
Share resources data files computing power videohellip
Information highway communication between geographically dispersed users
Electronic Society Cyberspace Virtual global nation
What is a Computer Network
5
Introduction Computer Network
ndash an interconnected collection of autonomous computersInternet ldquonetwork of networksrdquo
ndash loosely hierarchical
ndash public Internet versus private intranet
WWW a distributed systems run on the top of Internet
Distributed System
ndash High degree of cohesiveness and transparencyndash A software system built on top of a network
6
11 Uses of Computer Networks
bull Business Applications
bull Home Applications
bull Mobile Users
bull Social Issues
7
Business Applications of Networks
A network with two clients and one server
a Resource sharing (hardware software information hellip)
c Doing business electronically (B2B B2C e-commerce)
b Providing communication medium (e-mail videoconferenceing)
8
Goals of Networks for Companies Resource sharing equipment programs data high reliability
ndash replicated data
ndash hardware Saving money
ndash mainframe 10 times faster but 1000 times more expensive than PC
ndash client-server model Scalability
ndash mainframe replace a larger one
ndash client-server model add more servers Communication medium for separated employees
9
Business Applications of Networks (2)
The client-server model involves requests and replies
a Two processes are involved
b A communication network is needed
10
Home Network Applications
bull Access to remote information
bull Person-to-person communication
bull Interactive entertainment
bull Electronic commerce
11
Networks for Peoplendash Access to remote information
bull eg financial shopping customized newspapers on-line digital library WWW
ndash Person-to-person communicationbull email video conference newsgroup
ndash Interactive entertainmentbull VOD interactive movies or TVs game playing
12
Home Network Applications (2)
In peer-to-peer system there are no fixed clients and servers
13
Home Network Applications (3)
Some forms of e-commerce
14
Mobile Network Users
Combinations of wireless networks and mobile computing
mobile-commerce
15
Social Issues
bull Politics
bull Religion
bull Sex
bull Privacy
bull Crime
bull junk mail ill-information Each country has different laws Debate rages
16
Network Hardware
bull Local Area Networks
bull Metropolitan Area Networks
bull Wide Area Networks
bull Wireless Networks
bull Home Networks
bull Internetworks
17
Types of transmission technology
bull Broadcast links
bull Point-to-point links
Network Hardware
18
Network Hardwarendash Broadcast networks
bull single communication channel shared by all machines
bull broadcasting or multicasting (via packets)ndash broadcasting a special code in address field
ndash multicasting reserve one bit to indicate multicasting the remaining n-1address bits can hold a group number Each machine can subscribe to any groups
bull used by localized networks (or satellites)
ndash point-to-point networksbull many hops
bull routing algorithms multiple routs are possible
bull used by large networks
19
Classification of interconnected processors by scale
20
Local Area Networks (LANs)
Two broadcast networks(a) Bus(b) Ring
middot Characterics of LANs (a) privated-owned (b) small size (c) transmission technology (d) topology
middot Ethernets are most popular (up to 10 Gbs)
21
Local Area Networks Characteristics
ndash small size
ndash transmission technologybull single cable
bull 10Mbps ~ 10Gbs
bull 10Gbs 10000000000 bps
ndash topology
bull bus
ndash Ethernet (IEEE 8023) 10 or 100 Mbps (10Gbs)
bull ring
ndash IBM token ring (IEEE 8025) 4 or 16 Mbps
Channel allocation of broadcast networksndash static each machine has an allocated time slot
ndash dynamic
22
Metropolitan Area Networks
A metropolitan area network based on cable TV
23
Wide Area Networks (WANs)
Relation between hosts on LANs and the subnet
middotWANs are point-to-point networks
middotWANs consist of two distinct components transmission lines (copper fiber microwave) and switches (electronics optics)
Store-and-forward or packet-switched subnet
24
Network Topology
25
Subnet (WANs)Subnet (WANs) is consists of two components
ndash transmission lines (circuits channels trunks)bull move bits between machines
ndash switching elementsbull connect transmission lines
bull Router also called packet switching nodes intermediate systems and data switching exchanges
bull Operate in store-and-forward or packet-switched mode
26
Wide Area Networks (2)
A stream of packets from sender to receiver (virtual- circuit)
Routing decisions are made locallymiddot How A makes that decision is called the routing algorithm Will be studied in detail in Chapter 5
917 End
27
Wireless Networks
Categories of wireless networksbull System interconnection
(short-range radio eg Bluetooth)bull Wireless LANs
(80211a 80211b 80211g)bull Wireless WANs
(80216 Cellular telephones Satellites)bull Wireless sensor networks
28
Wireless Networks (2)
(a) Bluetooth configuration(b) Wireless LAN
29
Wireless Networks (3)
(a) Individual mobile computers(b) A flying LAN
30
Home Network Categories
Computers (desktop PC PDA shared peripherals) Entertainment (TV DVD VCR camera stereo MP3) Telecomm (telephone cell phone intercom fax) Appliances (microwave fridge clock furnace airco
light) Telemetry (utility meter smokeburglar alarm babycam)
31
Fundamentally different properties
1 Devices have to be easy to install
2 The network and devices have to be foolproof in
operation
3 Low price is essential
4 The network needs sufficient capacity ( for multimedia
application)
5 The network interface and wiring have to be stable for
many years
6 Security and reliability will be very important
(minimize false alarm or misalarm) Home networks may be wired or wireless
32
Internetworks
bull Internetworks connect networks with different hardware
and softwarebull A collection of interconnected networks is called
an internetwork or internetbull Internet is one specific internetbull Gateways are used to make the connection and to
provide the necessary translation (protocol convertion)
33
Network Software
bull Protocol Hierarchies (Layer structure)bull Design Issues for the Layersbull Connection-Oriented and Connectionless Servicesbull Service Primitivesbull The Relationship of Services to Protocols
34
Network Software
Protocol Hierarchiesndash a series of layers (levels)
ndash lower layer provides service to higher layers
ndash protocol bull an agreement between the communication parties on how
communication is to proceed
ndash Peers bull the corresponding layers on different machines
ndash Network architecture a set of layers and protocols
ndash Protocol stack bull a list of protocols used by a certain system one protocol per
layer
35
Network SoftwareProtocol Hierarchies
Layers protocols and interfaces
Peer
Network Architecture A set of layers and protocols Protocol Stack A list of protocols used by a certain system one protocol per layer
Virtual Communication
PhysicalCommunication
36
Layering
To make things simple modularization
Different layer has different functions
Create layer boundary such that description of services can be small number of interactions across boundary are minimized potential for interface standardized
Different level of abstraction in the handling of data (eg syntax semantics)
Provide appropriate services to upper layer
Use service primitives of lower layer
Network Software
37
Protocol Hierarchies (2)
The philosopher-translator-secretary architecture
38
Protocol Hierarchies (3)
Example information flow supporting virtual communication in layer 5
Message segmentation Encapsulation
39
Design Issues for the Layers
bull Addressing (telephone number e-mail address IP addresshellip)
bull Error Control (error correction codes ARQ HARQhellip)bull Flow Control (feedback-based rate-based)bull Multiplexing (gathering several small messages with the
same destination into a single large message or vice versa Demultiplexing)
bull Routing (directing traffic to the destination)
40
Design Issues for Layers
Identify senders and receivers ndash multiple computers and processes addressing
Data transferndash simplex half-duplex full-duplex communication
ndash of logical channels per connections priorities Error control
ndash error detection
ndash error correction Sequencing of pieces
41
Design Issues for Layers Flow control
ndash feedback from the receiver
ndash agreed upon transmission rate Length of messages
ndash long messages disassemble transmit and reassmeble messages
ndash short messages gather several small messages Multiplexing and Demultiplexing
ndash when expensive to set up a separate connection
ndash needed in physical layer Routing split over two or more layers
ndash High level London -gt France or Germany -gt Rome
ndash Low level many available circuits
42
Connection-Oriented and Connectionless Services
Six different types of service
43
Service Primitives (Operations)
Five service primitives for implementing a simple connection-oriented service
A service is formally defined by a set of primitives (operations) available to a user process to access the services
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
2
10 Technology Revolution
bull 18th Century Mechanical systems
bull 19th Century Steam Engine
bull 20th Century Information
- gathering
- distribution
- processing
- creating
3
A set of communication elements connected by communication links
Communication elements Computers printers mobile phones hellip Routers switches
Communication links optic fiber coaxial cable twisted pair wireless (radio microwave satellite)
Topologies Ring Star Bus Tree Mesh
What is a Computer Network
local ISP
companynetwork
regional ISP
router workstation
servermobile
4
A softwarehardware infrastructure
Share resources data files computing power videohellip
Information highway communication between geographically dispersed users
Electronic Society Cyberspace Virtual global nation
What is a Computer Network
5
Introduction Computer Network
ndash an interconnected collection of autonomous computersInternet ldquonetwork of networksrdquo
ndash loosely hierarchical
ndash public Internet versus private intranet
WWW a distributed systems run on the top of Internet
Distributed System
ndash High degree of cohesiveness and transparencyndash A software system built on top of a network
6
11 Uses of Computer Networks
bull Business Applications
bull Home Applications
bull Mobile Users
bull Social Issues
7
Business Applications of Networks
A network with two clients and one server
a Resource sharing (hardware software information hellip)
c Doing business electronically (B2B B2C e-commerce)
b Providing communication medium (e-mail videoconferenceing)
8
Goals of Networks for Companies Resource sharing equipment programs data high reliability
ndash replicated data
ndash hardware Saving money
ndash mainframe 10 times faster but 1000 times more expensive than PC
ndash client-server model Scalability
ndash mainframe replace a larger one
ndash client-server model add more servers Communication medium for separated employees
9
Business Applications of Networks (2)
The client-server model involves requests and replies
a Two processes are involved
b A communication network is needed
10
Home Network Applications
bull Access to remote information
bull Person-to-person communication
bull Interactive entertainment
bull Electronic commerce
11
Networks for Peoplendash Access to remote information
bull eg financial shopping customized newspapers on-line digital library WWW
ndash Person-to-person communicationbull email video conference newsgroup
ndash Interactive entertainmentbull VOD interactive movies or TVs game playing
12
Home Network Applications (2)
In peer-to-peer system there are no fixed clients and servers
13
Home Network Applications (3)
Some forms of e-commerce
14
Mobile Network Users
Combinations of wireless networks and mobile computing
mobile-commerce
15
Social Issues
bull Politics
bull Religion
bull Sex
bull Privacy
bull Crime
bull junk mail ill-information Each country has different laws Debate rages
16
Network Hardware
bull Local Area Networks
bull Metropolitan Area Networks
bull Wide Area Networks
bull Wireless Networks
bull Home Networks
bull Internetworks
17
Types of transmission technology
bull Broadcast links
bull Point-to-point links
Network Hardware
18
Network Hardwarendash Broadcast networks
bull single communication channel shared by all machines
bull broadcasting or multicasting (via packets)ndash broadcasting a special code in address field
ndash multicasting reserve one bit to indicate multicasting the remaining n-1address bits can hold a group number Each machine can subscribe to any groups
bull used by localized networks (or satellites)
ndash point-to-point networksbull many hops
bull routing algorithms multiple routs are possible
bull used by large networks
19
Classification of interconnected processors by scale
20
Local Area Networks (LANs)
Two broadcast networks(a) Bus(b) Ring
middot Characterics of LANs (a) privated-owned (b) small size (c) transmission technology (d) topology
middot Ethernets are most popular (up to 10 Gbs)
21
Local Area Networks Characteristics
ndash small size
ndash transmission technologybull single cable
bull 10Mbps ~ 10Gbs
bull 10Gbs 10000000000 bps
ndash topology
bull bus
ndash Ethernet (IEEE 8023) 10 or 100 Mbps (10Gbs)
bull ring
ndash IBM token ring (IEEE 8025) 4 or 16 Mbps
Channel allocation of broadcast networksndash static each machine has an allocated time slot
ndash dynamic
22
Metropolitan Area Networks
A metropolitan area network based on cable TV
23
Wide Area Networks (WANs)
Relation between hosts on LANs and the subnet
middotWANs are point-to-point networks
middotWANs consist of two distinct components transmission lines (copper fiber microwave) and switches (electronics optics)
Store-and-forward or packet-switched subnet
24
Network Topology
25
Subnet (WANs)Subnet (WANs) is consists of two components
ndash transmission lines (circuits channels trunks)bull move bits between machines
ndash switching elementsbull connect transmission lines
bull Router also called packet switching nodes intermediate systems and data switching exchanges
bull Operate in store-and-forward or packet-switched mode
26
Wide Area Networks (2)
A stream of packets from sender to receiver (virtual- circuit)
Routing decisions are made locallymiddot How A makes that decision is called the routing algorithm Will be studied in detail in Chapter 5
917 End
27
Wireless Networks
Categories of wireless networksbull System interconnection
(short-range radio eg Bluetooth)bull Wireless LANs
(80211a 80211b 80211g)bull Wireless WANs
(80216 Cellular telephones Satellites)bull Wireless sensor networks
28
Wireless Networks (2)
(a) Bluetooth configuration(b) Wireless LAN
29
Wireless Networks (3)
(a) Individual mobile computers(b) A flying LAN
30
Home Network Categories
Computers (desktop PC PDA shared peripherals) Entertainment (TV DVD VCR camera stereo MP3) Telecomm (telephone cell phone intercom fax) Appliances (microwave fridge clock furnace airco
light) Telemetry (utility meter smokeburglar alarm babycam)
31
Fundamentally different properties
1 Devices have to be easy to install
2 The network and devices have to be foolproof in
operation
3 Low price is essential
4 The network needs sufficient capacity ( for multimedia
application)
5 The network interface and wiring have to be stable for
many years
6 Security and reliability will be very important
(minimize false alarm or misalarm) Home networks may be wired or wireless
32
Internetworks
bull Internetworks connect networks with different hardware
and softwarebull A collection of interconnected networks is called
an internetwork or internetbull Internet is one specific internetbull Gateways are used to make the connection and to
provide the necessary translation (protocol convertion)
33
Network Software
bull Protocol Hierarchies (Layer structure)bull Design Issues for the Layersbull Connection-Oriented and Connectionless Servicesbull Service Primitivesbull The Relationship of Services to Protocols
34
Network Software
Protocol Hierarchiesndash a series of layers (levels)
ndash lower layer provides service to higher layers
ndash protocol bull an agreement between the communication parties on how
communication is to proceed
ndash Peers bull the corresponding layers on different machines
ndash Network architecture a set of layers and protocols
ndash Protocol stack bull a list of protocols used by a certain system one protocol per
layer
35
Network SoftwareProtocol Hierarchies
Layers protocols and interfaces
Peer
Network Architecture A set of layers and protocols Protocol Stack A list of protocols used by a certain system one protocol per layer
Virtual Communication
PhysicalCommunication
36
Layering
To make things simple modularization
Different layer has different functions
Create layer boundary such that description of services can be small number of interactions across boundary are minimized potential for interface standardized
Different level of abstraction in the handling of data (eg syntax semantics)
Provide appropriate services to upper layer
Use service primitives of lower layer
Network Software
37
Protocol Hierarchies (2)
The philosopher-translator-secretary architecture
38
Protocol Hierarchies (3)
Example information flow supporting virtual communication in layer 5
Message segmentation Encapsulation
39
Design Issues for the Layers
bull Addressing (telephone number e-mail address IP addresshellip)
bull Error Control (error correction codes ARQ HARQhellip)bull Flow Control (feedback-based rate-based)bull Multiplexing (gathering several small messages with the
same destination into a single large message or vice versa Demultiplexing)
bull Routing (directing traffic to the destination)
40
Design Issues for Layers
Identify senders and receivers ndash multiple computers and processes addressing
Data transferndash simplex half-duplex full-duplex communication
ndash of logical channels per connections priorities Error control
ndash error detection
ndash error correction Sequencing of pieces
41
Design Issues for Layers Flow control
ndash feedback from the receiver
ndash agreed upon transmission rate Length of messages
ndash long messages disassemble transmit and reassmeble messages
ndash short messages gather several small messages Multiplexing and Demultiplexing
ndash when expensive to set up a separate connection
ndash needed in physical layer Routing split over two or more layers
ndash High level London -gt France or Germany -gt Rome
ndash Low level many available circuits
42
Connection-Oriented and Connectionless Services
Six different types of service
43
Service Primitives (Operations)
Five service primitives for implementing a simple connection-oriented service
A service is formally defined by a set of primitives (operations) available to a user process to access the services
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
3
A set of communication elements connected by communication links
Communication elements Computers printers mobile phones hellip Routers switches
Communication links optic fiber coaxial cable twisted pair wireless (radio microwave satellite)
Topologies Ring Star Bus Tree Mesh
What is a Computer Network
local ISP
companynetwork
regional ISP
router workstation
servermobile
4
A softwarehardware infrastructure
Share resources data files computing power videohellip
Information highway communication between geographically dispersed users
Electronic Society Cyberspace Virtual global nation
What is a Computer Network
5
Introduction Computer Network
ndash an interconnected collection of autonomous computersInternet ldquonetwork of networksrdquo
ndash loosely hierarchical
ndash public Internet versus private intranet
WWW a distributed systems run on the top of Internet
Distributed System
ndash High degree of cohesiveness and transparencyndash A software system built on top of a network
6
11 Uses of Computer Networks
bull Business Applications
bull Home Applications
bull Mobile Users
bull Social Issues
7
Business Applications of Networks
A network with two clients and one server
a Resource sharing (hardware software information hellip)
c Doing business electronically (B2B B2C e-commerce)
b Providing communication medium (e-mail videoconferenceing)
8
Goals of Networks for Companies Resource sharing equipment programs data high reliability
ndash replicated data
ndash hardware Saving money
ndash mainframe 10 times faster but 1000 times more expensive than PC
ndash client-server model Scalability
ndash mainframe replace a larger one
ndash client-server model add more servers Communication medium for separated employees
9
Business Applications of Networks (2)
The client-server model involves requests and replies
a Two processes are involved
b A communication network is needed
10
Home Network Applications
bull Access to remote information
bull Person-to-person communication
bull Interactive entertainment
bull Electronic commerce
11
Networks for Peoplendash Access to remote information
bull eg financial shopping customized newspapers on-line digital library WWW
ndash Person-to-person communicationbull email video conference newsgroup
ndash Interactive entertainmentbull VOD interactive movies or TVs game playing
12
Home Network Applications (2)
In peer-to-peer system there are no fixed clients and servers
13
Home Network Applications (3)
Some forms of e-commerce
14
Mobile Network Users
Combinations of wireless networks and mobile computing
mobile-commerce
15
Social Issues
bull Politics
bull Religion
bull Sex
bull Privacy
bull Crime
bull junk mail ill-information Each country has different laws Debate rages
16
Network Hardware
bull Local Area Networks
bull Metropolitan Area Networks
bull Wide Area Networks
bull Wireless Networks
bull Home Networks
bull Internetworks
17
Types of transmission technology
bull Broadcast links
bull Point-to-point links
Network Hardware
18
Network Hardwarendash Broadcast networks
bull single communication channel shared by all machines
bull broadcasting or multicasting (via packets)ndash broadcasting a special code in address field
ndash multicasting reserve one bit to indicate multicasting the remaining n-1address bits can hold a group number Each machine can subscribe to any groups
bull used by localized networks (or satellites)
ndash point-to-point networksbull many hops
bull routing algorithms multiple routs are possible
bull used by large networks
19
Classification of interconnected processors by scale
20
Local Area Networks (LANs)
Two broadcast networks(a) Bus(b) Ring
middot Characterics of LANs (a) privated-owned (b) small size (c) transmission technology (d) topology
middot Ethernets are most popular (up to 10 Gbs)
21
Local Area Networks Characteristics
ndash small size
ndash transmission technologybull single cable
bull 10Mbps ~ 10Gbs
bull 10Gbs 10000000000 bps
ndash topology
bull bus
ndash Ethernet (IEEE 8023) 10 or 100 Mbps (10Gbs)
bull ring
ndash IBM token ring (IEEE 8025) 4 or 16 Mbps
Channel allocation of broadcast networksndash static each machine has an allocated time slot
ndash dynamic
22
Metropolitan Area Networks
A metropolitan area network based on cable TV
23
Wide Area Networks (WANs)
Relation between hosts on LANs and the subnet
middotWANs are point-to-point networks
middotWANs consist of two distinct components transmission lines (copper fiber microwave) and switches (electronics optics)
Store-and-forward or packet-switched subnet
24
Network Topology
25
Subnet (WANs)Subnet (WANs) is consists of two components
ndash transmission lines (circuits channels trunks)bull move bits between machines
ndash switching elementsbull connect transmission lines
bull Router also called packet switching nodes intermediate systems and data switching exchanges
bull Operate in store-and-forward or packet-switched mode
26
Wide Area Networks (2)
A stream of packets from sender to receiver (virtual- circuit)
Routing decisions are made locallymiddot How A makes that decision is called the routing algorithm Will be studied in detail in Chapter 5
917 End
27
Wireless Networks
Categories of wireless networksbull System interconnection
(short-range radio eg Bluetooth)bull Wireless LANs
(80211a 80211b 80211g)bull Wireless WANs
(80216 Cellular telephones Satellites)bull Wireless sensor networks
28
Wireless Networks (2)
(a) Bluetooth configuration(b) Wireless LAN
29
Wireless Networks (3)
(a) Individual mobile computers(b) A flying LAN
30
Home Network Categories
Computers (desktop PC PDA shared peripherals) Entertainment (TV DVD VCR camera stereo MP3) Telecomm (telephone cell phone intercom fax) Appliances (microwave fridge clock furnace airco
light) Telemetry (utility meter smokeburglar alarm babycam)
31
Fundamentally different properties
1 Devices have to be easy to install
2 The network and devices have to be foolproof in
operation
3 Low price is essential
4 The network needs sufficient capacity ( for multimedia
application)
5 The network interface and wiring have to be stable for
many years
6 Security and reliability will be very important
(minimize false alarm or misalarm) Home networks may be wired or wireless
32
Internetworks
bull Internetworks connect networks with different hardware
and softwarebull A collection of interconnected networks is called
an internetwork or internetbull Internet is one specific internetbull Gateways are used to make the connection and to
provide the necessary translation (protocol convertion)
33
Network Software
bull Protocol Hierarchies (Layer structure)bull Design Issues for the Layersbull Connection-Oriented and Connectionless Servicesbull Service Primitivesbull The Relationship of Services to Protocols
34
Network Software
Protocol Hierarchiesndash a series of layers (levels)
ndash lower layer provides service to higher layers
ndash protocol bull an agreement between the communication parties on how
communication is to proceed
ndash Peers bull the corresponding layers on different machines
ndash Network architecture a set of layers and protocols
ndash Protocol stack bull a list of protocols used by a certain system one protocol per
layer
35
Network SoftwareProtocol Hierarchies
Layers protocols and interfaces
Peer
Network Architecture A set of layers and protocols Protocol Stack A list of protocols used by a certain system one protocol per layer
Virtual Communication
PhysicalCommunication
36
Layering
To make things simple modularization
Different layer has different functions
Create layer boundary such that description of services can be small number of interactions across boundary are minimized potential for interface standardized
Different level of abstraction in the handling of data (eg syntax semantics)
Provide appropriate services to upper layer
Use service primitives of lower layer
Network Software
37
Protocol Hierarchies (2)
The philosopher-translator-secretary architecture
38
Protocol Hierarchies (3)
Example information flow supporting virtual communication in layer 5
Message segmentation Encapsulation
39
Design Issues for the Layers
bull Addressing (telephone number e-mail address IP addresshellip)
bull Error Control (error correction codes ARQ HARQhellip)bull Flow Control (feedback-based rate-based)bull Multiplexing (gathering several small messages with the
same destination into a single large message or vice versa Demultiplexing)
bull Routing (directing traffic to the destination)
40
Design Issues for Layers
Identify senders and receivers ndash multiple computers and processes addressing
Data transferndash simplex half-duplex full-duplex communication
ndash of logical channels per connections priorities Error control
ndash error detection
ndash error correction Sequencing of pieces
41
Design Issues for Layers Flow control
ndash feedback from the receiver
ndash agreed upon transmission rate Length of messages
ndash long messages disassemble transmit and reassmeble messages
ndash short messages gather several small messages Multiplexing and Demultiplexing
ndash when expensive to set up a separate connection
ndash needed in physical layer Routing split over two or more layers
ndash High level London -gt France or Germany -gt Rome
ndash Low level many available circuits
42
Connection-Oriented and Connectionless Services
Six different types of service
43
Service Primitives (Operations)
Five service primitives for implementing a simple connection-oriented service
A service is formally defined by a set of primitives (operations) available to a user process to access the services
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
4
A softwarehardware infrastructure
Share resources data files computing power videohellip
Information highway communication between geographically dispersed users
Electronic Society Cyberspace Virtual global nation
What is a Computer Network
5
Introduction Computer Network
ndash an interconnected collection of autonomous computersInternet ldquonetwork of networksrdquo
ndash loosely hierarchical
ndash public Internet versus private intranet
WWW a distributed systems run on the top of Internet
Distributed System
ndash High degree of cohesiveness and transparencyndash A software system built on top of a network
6
11 Uses of Computer Networks
bull Business Applications
bull Home Applications
bull Mobile Users
bull Social Issues
7
Business Applications of Networks
A network with two clients and one server
a Resource sharing (hardware software information hellip)
c Doing business electronically (B2B B2C e-commerce)
b Providing communication medium (e-mail videoconferenceing)
8
Goals of Networks for Companies Resource sharing equipment programs data high reliability
ndash replicated data
ndash hardware Saving money
ndash mainframe 10 times faster but 1000 times more expensive than PC
ndash client-server model Scalability
ndash mainframe replace a larger one
ndash client-server model add more servers Communication medium for separated employees
9
Business Applications of Networks (2)
The client-server model involves requests and replies
a Two processes are involved
b A communication network is needed
10
Home Network Applications
bull Access to remote information
bull Person-to-person communication
bull Interactive entertainment
bull Electronic commerce
11
Networks for Peoplendash Access to remote information
bull eg financial shopping customized newspapers on-line digital library WWW
ndash Person-to-person communicationbull email video conference newsgroup
ndash Interactive entertainmentbull VOD interactive movies or TVs game playing
12
Home Network Applications (2)
In peer-to-peer system there are no fixed clients and servers
13
Home Network Applications (3)
Some forms of e-commerce
14
Mobile Network Users
Combinations of wireless networks and mobile computing
mobile-commerce
15
Social Issues
bull Politics
bull Religion
bull Sex
bull Privacy
bull Crime
bull junk mail ill-information Each country has different laws Debate rages
16
Network Hardware
bull Local Area Networks
bull Metropolitan Area Networks
bull Wide Area Networks
bull Wireless Networks
bull Home Networks
bull Internetworks
17
Types of transmission technology
bull Broadcast links
bull Point-to-point links
Network Hardware
18
Network Hardwarendash Broadcast networks
bull single communication channel shared by all machines
bull broadcasting or multicasting (via packets)ndash broadcasting a special code in address field
ndash multicasting reserve one bit to indicate multicasting the remaining n-1address bits can hold a group number Each machine can subscribe to any groups
bull used by localized networks (or satellites)
ndash point-to-point networksbull many hops
bull routing algorithms multiple routs are possible
bull used by large networks
19
Classification of interconnected processors by scale
20
Local Area Networks (LANs)
Two broadcast networks(a) Bus(b) Ring
middot Characterics of LANs (a) privated-owned (b) small size (c) transmission technology (d) topology
middot Ethernets are most popular (up to 10 Gbs)
21
Local Area Networks Characteristics
ndash small size
ndash transmission technologybull single cable
bull 10Mbps ~ 10Gbs
bull 10Gbs 10000000000 bps
ndash topology
bull bus
ndash Ethernet (IEEE 8023) 10 or 100 Mbps (10Gbs)
bull ring
ndash IBM token ring (IEEE 8025) 4 or 16 Mbps
Channel allocation of broadcast networksndash static each machine has an allocated time slot
ndash dynamic
22
Metropolitan Area Networks
A metropolitan area network based on cable TV
23
Wide Area Networks (WANs)
Relation between hosts on LANs and the subnet
middotWANs are point-to-point networks
middotWANs consist of two distinct components transmission lines (copper fiber microwave) and switches (electronics optics)
Store-and-forward or packet-switched subnet
24
Network Topology
25
Subnet (WANs)Subnet (WANs) is consists of two components
ndash transmission lines (circuits channels trunks)bull move bits between machines
ndash switching elementsbull connect transmission lines
bull Router also called packet switching nodes intermediate systems and data switching exchanges
bull Operate in store-and-forward or packet-switched mode
26
Wide Area Networks (2)
A stream of packets from sender to receiver (virtual- circuit)
Routing decisions are made locallymiddot How A makes that decision is called the routing algorithm Will be studied in detail in Chapter 5
917 End
27
Wireless Networks
Categories of wireless networksbull System interconnection
(short-range radio eg Bluetooth)bull Wireless LANs
(80211a 80211b 80211g)bull Wireless WANs
(80216 Cellular telephones Satellites)bull Wireless sensor networks
28
Wireless Networks (2)
(a) Bluetooth configuration(b) Wireless LAN
29
Wireless Networks (3)
(a) Individual mobile computers(b) A flying LAN
30
Home Network Categories
Computers (desktop PC PDA shared peripherals) Entertainment (TV DVD VCR camera stereo MP3) Telecomm (telephone cell phone intercom fax) Appliances (microwave fridge clock furnace airco
light) Telemetry (utility meter smokeburglar alarm babycam)
31
Fundamentally different properties
1 Devices have to be easy to install
2 The network and devices have to be foolproof in
operation
3 Low price is essential
4 The network needs sufficient capacity ( for multimedia
application)
5 The network interface and wiring have to be stable for
many years
6 Security and reliability will be very important
(minimize false alarm or misalarm) Home networks may be wired or wireless
32
Internetworks
bull Internetworks connect networks with different hardware
and softwarebull A collection of interconnected networks is called
an internetwork or internetbull Internet is one specific internetbull Gateways are used to make the connection and to
provide the necessary translation (protocol convertion)
33
Network Software
bull Protocol Hierarchies (Layer structure)bull Design Issues for the Layersbull Connection-Oriented and Connectionless Servicesbull Service Primitivesbull The Relationship of Services to Protocols
34
Network Software
Protocol Hierarchiesndash a series of layers (levels)
ndash lower layer provides service to higher layers
ndash protocol bull an agreement between the communication parties on how
communication is to proceed
ndash Peers bull the corresponding layers on different machines
ndash Network architecture a set of layers and protocols
ndash Protocol stack bull a list of protocols used by a certain system one protocol per
layer
35
Network SoftwareProtocol Hierarchies
Layers protocols and interfaces
Peer
Network Architecture A set of layers and protocols Protocol Stack A list of protocols used by a certain system one protocol per layer
Virtual Communication
PhysicalCommunication
36
Layering
To make things simple modularization
Different layer has different functions
Create layer boundary such that description of services can be small number of interactions across boundary are minimized potential for interface standardized
Different level of abstraction in the handling of data (eg syntax semantics)
Provide appropriate services to upper layer
Use service primitives of lower layer
Network Software
37
Protocol Hierarchies (2)
The philosopher-translator-secretary architecture
38
Protocol Hierarchies (3)
Example information flow supporting virtual communication in layer 5
Message segmentation Encapsulation
39
Design Issues for the Layers
bull Addressing (telephone number e-mail address IP addresshellip)
bull Error Control (error correction codes ARQ HARQhellip)bull Flow Control (feedback-based rate-based)bull Multiplexing (gathering several small messages with the
same destination into a single large message or vice versa Demultiplexing)
bull Routing (directing traffic to the destination)
40
Design Issues for Layers
Identify senders and receivers ndash multiple computers and processes addressing
Data transferndash simplex half-duplex full-duplex communication
ndash of logical channels per connections priorities Error control
ndash error detection
ndash error correction Sequencing of pieces
41
Design Issues for Layers Flow control
ndash feedback from the receiver
ndash agreed upon transmission rate Length of messages
ndash long messages disassemble transmit and reassmeble messages
ndash short messages gather several small messages Multiplexing and Demultiplexing
ndash when expensive to set up a separate connection
ndash needed in physical layer Routing split over two or more layers
ndash High level London -gt France or Germany -gt Rome
ndash Low level many available circuits
42
Connection-Oriented and Connectionless Services
Six different types of service
43
Service Primitives (Operations)
Five service primitives for implementing a simple connection-oriented service
A service is formally defined by a set of primitives (operations) available to a user process to access the services
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
5
Introduction Computer Network
ndash an interconnected collection of autonomous computersInternet ldquonetwork of networksrdquo
ndash loosely hierarchical
ndash public Internet versus private intranet
WWW a distributed systems run on the top of Internet
Distributed System
ndash High degree of cohesiveness and transparencyndash A software system built on top of a network
6
11 Uses of Computer Networks
bull Business Applications
bull Home Applications
bull Mobile Users
bull Social Issues
7
Business Applications of Networks
A network with two clients and one server
a Resource sharing (hardware software information hellip)
c Doing business electronically (B2B B2C e-commerce)
b Providing communication medium (e-mail videoconferenceing)
8
Goals of Networks for Companies Resource sharing equipment programs data high reliability
ndash replicated data
ndash hardware Saving money
ndash mainframe 10 times faster but 1000 times more expensive than PC
ndash client-server model Scalability
ndash mainframe replace a larger one
ndash client-server model add more servers Communication medium for separated employees
9
Business Applications of Networks (2)
The client-server model involves requests and replies
a Two processes are involved
b A communication network is needed
10
Home Network Applications
bull Access to remote information
bull Person-to-person communication
bull Interactive entertainment
bull Electronic commerce
11
Networks for Peoplendash Access to remote information
bull eg financial shopping customized newspapers on-line digital library WWW
ndash Person-to-person communicationbull email video conference newsgroup
ndash Interactive entertainmentbull VOD interactive movies or TVs game playing
12
Home Network Applications (2)
In peer-to-peer system there are no fixed clients and servers
13
Home Network Applications (3)
Some forms of e-commerce
14
Mobile Network Users
Combinations of wireless networks and mobile computing
mobile-commerce
15
Social Issues
bull Politics
bull Religion
bull Sex
bull Privacy
bull Crime
bull junk mail ill-information Each country has different laws Debate rages
16
Network Hardware
bull Local Area Networks
bull Metropolitan Area Networks
bull Wide Area Networks
bull Wireless Networks
bull Home Networks
bull Internetworks
17
Types of transmission technology
bull Broadcast links
bull Point-to-point links
Network Hardware
18
Network Hardwarendash Broadcast networks
bull single communication channel shared by all machines
bull broadcasting or multicasting (via packets)ndash broadcasting a special code in address field
ndash multicasting reserve one bit to indicate multicasting the remaining n-1address bits can hold a group number Each machine can subscribe to any groups
bull used by localized networks (or satellites)
ndash point-to-point networksbull many hops
bull routing algorithms multiple routs are possible
bull used by large networks
19
Classification of interconnected processors by scale
20
Local Area Networks (LANs)
Two broadcast networks(a) Bus(b) Ring
middot Characterics of LANs (a) privated-owned (b) small size (c) transmission technology (d) topology
middot Ethernets are most popular (up to 10 Gbs)
21
Local Area Networks Characteristics
ndash small size
ndash transmission technologybull single cable
bull 10Mbps ~ 10Gbs
bull 10Gbs 10000000000 bps
ndash topology
bull bus
ndash Ethernet (IEEE 8023) 10 or 100 Mbps (10Gbs)
bull ring
ndash IBM token ring (IEEE 8025) 4 or 16 Mbps
Channel allocation of broadcast networksndash static each machine has an allocated time slot
ndash dynamic
22
Metropolitan Area Networks
A metropolitan area network based on cable TV
23
Wide Area Networks (WANs)
Relation between hosts on LANs and the subnet
middotWANs are point-to-point networks
middotWANs consist of two distinct components transmission lines (copper fiber microwave) and switches (electronics optics)
Store-and-forward or packet-switched subnet
24
Network Topology
25
Subnet (WANs)Subnet (WANs) is consists of two components
ndash transmission lines (circuits channels trunks)bull move bits between machines
ndash switching elementsbull connect transmission lines
bull Router also called packet switching nodes intermediate systems and data switching exchanges
bull Operate in store-and-forward or packet-switched mode
26
Wide Area Networks (2)
A stream of packets from sender to receiver (virtual- circuit)
Routing decisions are made locallymiddot How A makes that decision is called the routing algorithm Will be studied in detail in Chapter 5
917 End
27
Wireless Networks
Categories of wireless networksbull System interconnection
(short-range radio eg Bluetooth)bull Wireless LANs
(80211a 80211b 80211g)bull Wireless WANs
(80216 Cellular telephones Satellites)bull Wireless sensor networks
28
Wireless Networks (2)
(a) Bluetooth configuration(b) Wireless LAN
29
Wireless Networks (3)
(a) Individual mobile computers(b) A flying LAN
30
Home Network Categories
Computers (desktop PC PDA shared peripherals) Entertainment (TV DVD VCR camera stereo MP3) Telecomm (telephone cell phone intercom fax) Appliances (microwave fridge clock furnace airco
light) Telemetry (utility meter smokeburglar alarm babycam)
31
Fundamentally different properties
1 Devices have to be easy to install
2 The network and devices have to be foolproof in
operation
3 Low price is essential
4 The network needs sufficient capacity ( for multimedia
application)
5 The network interface and wiring have to be stable for
many years
6 Security and reliability will be very important
(minimize false alarm or misalarm) Home networks may be wired or wireless
32
Internetworks
bull Internetworks connect networks with different hardware
and softwarebull A collection of interconnected networks is called
an internetwork or internetbull Internet is one specific internetbull Gateways are used to make the connection and to
provide the necessary translation (protocol convertion)
33
Network Software
bull Protocol Hierarchies (Layer structure)bull Design Issues for the Layersbull Connection-Oriented and Connectionless Servicesbull Service Primitivesbull The Relationship of Services to Protocols
34
Network Software
Protocol Hierarchiesndash a series of layers (levels)
ndash lower layer provides service to higher layers
ndash protocol bull an agreement between the communication parties on how
communication is to proceed
ndash Peers bull the corresponding layers on different machines
ndash Network architecture a set of layers and protocols
ndash Protocol stack bull a list of protocols used by a certain system one protocol per
layer
35
Network SoftwareProtocol Hierarchies
Layers protocols and interfaces
Peer
Network Architecture A set of layers and protocols Protocol Stack A list of protocols used by a certain system one protocol per layer
Virtual Communication
PhysicalCommunication
36
Layering
To make things simple modularization
Different layer has different functions
Create layer boundary such that description of services can be small number of interactions across boundary are minimized potential for interface standardized
Different level of abstraction in the handling of data (eg syntax semantics)
Provide appropriate services to upper layer
Use service primitives of lower layer
Network Software
37
Protocol Hierarchies (2)
The philosopher-translator-secretary architecture
38
Protocol Hierarchies (3)
Example information flow supporting virtual communication in layer 5
Message segmentation Encapsulation
39
Design Issues for the Layers
bull Addressing (telephone number e-mail address IP addresshellip)
bull Error Control (error correction codes ARQ HARQhellip)bull Flow Control (feedback-based rate-based)bull Multiplexing (gathering several small messages with the
same destination into a single large message or vice versa Demultiplexing)
bull Routing (directing traffic to the destination)
40
Design Issues for Layers
Identify senders and receivers ndash multiple computers and processes addressing
Data transferndash simplex half-duplex full-duplex communication
ndash of logical channels per connections priorities Error control
ndash error detection
ndash error correction Sequencing of pieces
41
Design Issues for Layers Flow control
ndash feedback from the receiver
ndash agreed upon transmission rate Length of messages
ndash long messages disassemble transmit and reassmeble messages
ndash short messages gather several small messages Multiplexing and Demultiplexing
ndash when expensive to set up a separate connection
ndash needed in physical layer Routing split over two or more layers
ndash High level London -gt France or Germany -gt Rome
ndash Low level many available circuits
42
Connection-Oriented and Connectionless Services
Six different types of service
43
Service Primitives (Operations)
Five service primitives for implementing a simple connection-oriented service
A service is formally defined by a set of primitives (operations) available to a user process to access the services
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
6
11 Uses of Computer Networks
bull Business Applications
bull Home Applications
bull Mobile Users
bull Social Issues
7
Business Applications of Networks
A network with two clients and one server
a Resource sharing (hardware software information hellip)
c Doing business electronically (B2B B2C e-commerce)
b Providing communication medium (e-mail videoconferenceing)
8
Goals of Networks for Companies Resource sharing equipment programs data high reliability
ndash replicated data
ndash hardware Saving money
ndash mainframe 10 times faster but 1000 times more expensive than PC
ndash client-server model Scalability
ndash mainframe replace a larger one
ndash client-server model add more servers Communication medium for separated employees
9
Business Applications of Networks (2)
The client-server model involves requests and replies
a Two processes are involved
b A communication network is needed
10
Home Network Applications
bull Access to remote information
bull Person-to-person communication
bull Interactive entertainment
bull Electronic commerce
11
Networks for Peoplendash Access to remote information
bull eg financial shopping customized newspapers on-line digital library WWW
ndash Person-to-person communicationbull email video conference newsgroup
ndash Interactive entertainmentbull VOD interactive movies or TVs game playing
12
Home Network Applications (2)
In peer-to-peer system there are no fixed clients and servers
13
Home Network Applications (3)
Some forms of e-commerce
14
Mobile Network Users
Combinations of wireless networks and mobile computing
mobile-commerce
15
Social Issues
bull Politics
bull Religion
bull Sex
bull Privacy
bull Crime
bull junk mail ill-information Each country has different laws Debate rages
16
Network Hardware
bull Local Area Networks
bull Metropolitan Area Networks
bull Wide Area Networks
bull Wireless Networks
bull Home Networks
bull Internetworks
17
Types of transmission technology
bull Broadcast links
bull Point-to-point links
Network Hardware
18
Network Hardwarendash Broadcast networks
bull single communication channel shared by all machines
bull broadcasting or multicasting (via packets)ndash broadcasting a special code in address field
ndash multicasting reserve one bit to indicate multicasting the remaining n-1address bits can hold a group number Each machine can subscribe to any groups
bull used by localized networks (or satellites)
ndash point-to-point networksbull many hops
bull routing algorithms multiple routs are possible
bull used by large networks
19
Classification of interconnected processors by scale
20
Local Area Networks (LANs)
Two broadcast networks(a) Bus(b) Ring
middot Characterics of LANs (a) privated-owned (b) small size (c) transmission technology (d) topology
middot Ethernets are most popular (up to 10 Gbs)
21
Local Area Networks Characteristics
ndash small size
ndash transmission technologybull single cable
bull 10Mbps ~ 10Gbs
bull 10Gbs 10000000000 bps
ndash topology
bull bus
ndash Ethernet (IEEE 8023) 10 or 100 Mbps (10Gbs)
bull ring
ndash IBM token ring (IEEE 8025) 4 or 16 Mbps
Channel allocation of broadcast networksndash static each machine has an allocated time slot
ndash dynamic
22
Metropolitan Area Networks
A metropolitan area network based on cable TV
23
Wide Area Networks (WANs)
Relation between hosts on LANs and the subnet
middotWANs are point-to-point networks
middotWANs consist of two distinct components transmission lines (copper fiber microwave) and switches (electronics optics)
Store-and-forward or packet-switched subnet
24
Network Topology
25
Subnet (WANs)Subnet (WANs) is consists of two components
ndash transmission lines (circuits channels trunks)bull move bits between machines
ndash switching elementsbull connect transmission lines
bull Router also called packet switching nodes intermediate systems and data switching exchanges
bull Operate in store-and-forward or packet-switched mode
26
Wide Area Networks (2)
A stream of packets from sender to receiver (virtual- circuit)
Routing decisions are made locallymiddot How A makes that decision is called the routing algorithm Will be studied in detail in Chapter 5
917 End
27
Wireless Networks
Categories of wireless networksbull System interconnection
(short-range radio eg Bluetooth)bull Wireless LANs
(80211a 80211b 80211g)bull Wireless WANs
(80216 Cellular telephones Satellites)bull Wireless sensor networks
28
Wireless Networks (2)
(a) Bluetooth configuration(b) Wireless LAN
29
Wireless Networks (3)
(a) Individual mobile computers(b) A flying LAN
30
Home Network Categories
Computers (desktop PC PDA shared peripherals) Entertainment (TV DVD VCR camera stereo MP3) Telecomm (telephone cell phone intercom fax) Appliances (microwave fridge clock furnace airco
light) Telemetry (utility meter smokeburglar alarm babycam)
31
Fundamentally different properties
1 Devices have to be easy to install
2 The network and devices have to be foolproof in
operation
3 Low price is essential
4 The network needs sufficient capacity ( for multimedia
application)
5 The network interface and wiring have to be stable for
many years
6 Security and reliability will be very important
(minimize false alarm or misalarm) Home networks may be wired or wireless
32
Internetworks
bull Internetworks connect networks with different hardware
and softwarebull A collection of interconnected networks is called
an internetwork or internetbull Internet is one specific internetbull Gateways are used to make the connection and to
provide the necessary translation (protocol convertion)
33
Network Software
bull Protocol Hierarchies (Layer structure)bull Design Issues for the Layersbull Connection-Oriented and Connectionless Servicesbull Service Primitivesbull The Relationship of Services to Protocols
34
Network Software
Protocol Hierarchiesndash a series of layers (levels)
ndash lower layer provides service to higher layers
ndash protocol bull an agreement between the communication parties on how
communication is to proceed
ndash Peers bull the corresponding layers on different machines
ndash Network architecture a set of layers and protocols
ndash Protocol stack bull a list of protocols used by a certain system one protocol per
layer
35
Network SoftwareProtocol Hierarchies
Layers protocols and interfaces
Peer
Network Architecture A set of layers and protocols Protocol Stack A list of protocols used by a certain system one protocol per layer
Virtual Communication
PhysicalCommunication
36
Layering
To make things simple modularization
Different layer has different functions
Create layer boundary such that description of services can be small number of interactions across boundary are minimized potential for interface standardized
Different level of abstraction in the handling of data (eg syntax semantics)
Provide appropriate services to upper layer
Use service primitives of lower layer
Network Software
37
Protocol Hierarchies (2)
The philosopher-translator-secretary architecture
38
Protocol Hierarchies (3)
Example information flow supporting virtual communication in layer 5
Message segmentation Encapsulation
39
Design Issues for the Layers
bull Addressing (telephone number e-mail address IP addresshellip)
bull Error Control (error correction codes ARQ HARQhellip)bull Flow Control (feedback-based rate-based)bull Multiplexing (gathering several small messages with the
same destination into a single large message or vice versa Demultiplexing)
bull Routing (directing traffic to the destination)
40
Design Issues for Layers
Identify senders and receivers ndash multiple computers and processes addressing
Data transferndash simplex half-duplex full-duplex communication
ndash of logical channels per connections priorities Error control
ndash error detection
ndash error correction Sequencing of pieces
41
Design Issues for Layers Flow control
ndash feedback from the receiver
ndash agreed upon transmission rate Length of messages
ndash long messages disassemble transmit and reassmeble messages
ndash short messages gather several small messages Multiplexing and Demultiplexing
ndash when expensive to set up a separate connection
ndash needed in physical layer Routing split over two or more layers
ndash High level London -gt France or Germany -gt Rome
ndash Low level many available circuits
42
Connection-Oriented and Connectionless Services
Six different types of service
43
Service Primitives (Operations)
Five service primitives for implementing a simple connection-oriented service
A service is formally defined by a set of primitives (operations) available to a user process to access the services
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
7
Business Applications of Networks
A network with two clients and one server
a Resource sharing (hardware software information hellip)
c Doing business electronically (B2B B2C e-commerce)
b Providing communication medium (e-mail videoconferenceing)
8
Goals of Networks for Companies Resource sharing equipment programs data high reliability
ndash replicated data
ndash hardware Saving money
ndash mainframe 10 times faster but 1000 times more expensive than PC
ndash client-server model Scalability
ndash mainframe replace a larger one
ndash client-server model add more servers Communication medium for separated employees
9
Business Applications of Networks (2)
The client-server model involves requests and replies
a Two processes are involved
b A communication network is needed
10
Home Network Applications
bull Access to remote information
bull Person-to-person communication
bull Interactive entertainment
bull Electronic commerce
11
Networks for Peoplendash Access to remote information
bull eg financial shopping customized newspapers on-line digital library WWW
ndash Person-to-person communicationbull email video conference newsgroup
ndash Interactive entertainmentbull VOD interactive movies or TVs game playing
12
Home Network Applications (2)
In peer-to-peer system there are no fixed clients and servers
13
Home Network Applications (3)
Some forms of e-commerce
14
Mobile Network Users
Combinations of wireless networks and mobile computing
mobile-commerce
15
Social Issues
bull Politics
bull Religion
bull Sex
bull Privacy
bull Crime
bull junk mail ill-information Each country has different laws Debate rages
16
Network Hardware
bull Local Area Networks
bull Metropolitan Area Networks
bull Wide Area Networks
bull Wireless Networks
bull Home Networks
bull Internetworks
17
Types of transmission technology
bull Broadcast links
bull Point-to-point links
Network Hardware
18
Network Hardwarendash Broadcast networks
bull single communication channel shared by all machines
bull broadcasting or multicasting (via packets)ndash broadcasting a special code in address field
ndash multicasting reserve one bit to indicate multicasting the remaining n-1address bits can hold a group number Each machine can subscribe to any groups
bull used by localized networks (or satellites)
ndash point-to-point networksbull many hops
bull routing algorithms multiple routs are possible
bull used by large networks
19
Classification of interconnected processors by scale
20
Local Area Networks (LANs)
Two broadcast networks(a) Bus(b) Ring
middot Characterics of LANs (a) privated-owned (b) small size (c) transmission technology (d) topology
middot Ethernets are most popular (up to 10 Gbs)
21
Local Area Networks Characteristics
ndash small size
ndash transmission technologybull single cable
bull 10Mbps ~ 10Gbs
bull 10Gbs 10000000000 bps
ndash topology
bull bus
ndash Ethernet (IEEE 8023) 10 or 100 Mbps (10Gbs)
bull ring
ndash IBM token ring (IEEE 8025) 4 or 16 Mbps
Channel allocation of broadcast networksndash static each machine has an allocated time slot
ndash dynamic
22
Metropolitan Area Networks
A metropolitan area network based on cable TV
23
Wide Area Networks (WANs)
Relation between hosts on LANs and the subnet
middotWANs are point-to-point networks
middotWANs consist of two distinct components transmission lines (copper fiber microwave) and switches (electronics optics)
Store-and-forward or packet-switched subnet
24
Network Topology
25
Subnet (WANs)Subnet (WANs) is consists of two components
ndash transmission lines (circuits channels trunks)bull move bits between machines
ndash switching elementsbull connect transmission lines
bull Router also called packet switching nodes intermediate systems and data switching exchanges
bull Operate in store-and-forward or packet-switched mode
26
Wide Area Networks (2)
A stream of packets from sender to receiver (virtual- circuit)
Routing decisions are made locallymiddot How A makes that decision is called the routing algorithm Will be studied in detail in Chapter 5
917 End
27
Wireless Networks
Categories of wireless networksbull System interconnection
(short-range radio eg Bluetooth)bull Wireless LANs
(80211a 80211b 80211g)bull Wireless WANs
(80216 Cellular telephones Satellites)bull Wireless sensor networks
28
Wireless Networks (2)
(a) Bluetooth configuration(b) Wireless LAN
29
Wireless Networks (3)
(a) Individual mobile computers(b) A flying LAN
30
Home Network Categories
Computers (desktop PC PDA shared peripherals) Entertainment (TV DVD VCR camera stereo MP3) Telecomm (telephone cell phone intercom fax) Appliances (microwave fridge clock furnace airco
light) Telemetry (utility meter smokeburglar alarm babycam)
31
Fundamentally different properties
1 Devices have to be easy to install
2 The network and devices have to be foolproof in
operation
3 Low price is essential
4 The network needs sufficient capacity ( for multimedia
application)
5 The network interface and wiring have to be stable for
many years
6 Security and reliability will be very important
(minimize false alarm or misalarm) Home networks may be wired or wireless
32
Internetworks
bull Internetworks connect networks with different hardware
and softwarebull A collection of interconnected networks is called
an internetwork or internetbull Internet is one specific internetbull Gateways are used to make the connection and to
provide the necessary translation (protocol convertion)
33
Network Software
bull Protocol Hierarchies (Layer structure)bull Design Issues for the Layersbull Connection-Oriented and Connectionless Servicesbull Service Primitivesbull The Relationship of Services to Protocols
34
Network Software
Protocol Hierarchiesndash a series of layers (levels)
ndash lower layer provides service to higher layers
ndash protocol bull an agreement between the communication parties on how
communication is to proceed
ndash Peers bull the corresponding layers on different machines
ndash Network architecture a set of layers and protocols
ndash Protocol stack bull a list of protocols used by a certain system one protocol per
layer
35
Network SoftwareProtocol Hierarchies
Layers protocols and interfaces
Peer
Network Architecture A set of layers and protocols Protocol Stack A list of protocols used by a certain system one protocol per layer
Virtual Communication
PhysicalCommunication
36
Layering
To make things simple modularization
Different layer has different functions
Create layer boundary such that description of services can be small number of interactions across boundary are minimized potential for interface standardized
Different level of abstraction in the handling of data (eg syntax semantics)
Provide appropriate services to upper layer
Use service primitives of lower layer
Network Software
37
Protocol Hierarchies (2)
The philosopher-translator-secretary architecture
38
Protocol Hierarchies (3)
Example information flow supporting virtual communication in layer 5
Message segmentation Encapsulation
39
Design Issues for the Layers
bull Addressing (telephone number e-mail address IP addresshellip)
bull Error Control (error correction codes ARQ HARQhellip)bull Flow Control (feedback-based rate-based)bull Multiplexing (gathering several small messages with the
same destination into a single large message or vice versa Demultiplexing)
bull Routing (directing traffic to the destination)
40
Design Issues for Layers
Identify senders and receivers ndash multiple computers and processes addressing
Data transferndash simplex half-duplex full-duplex communication
ndash of logical channels per connections priorities Error control
ndash error detection
ndash error correction Sequencing of pieces
41
Design Issues for Layers Flow control
ndash feedback from the receiver
ndash agreed upon transmission rate Length of messages
ndash long messages disassemble transmit and reassmeble messages
ndash short messages gather several small messages Multiplexing and Demultiplexing
ndash when expensive to set up a separate connection
ndash needed in physical layer Routing split over two or more layers
ndash High level London -gt France or Germany -gt Rome
ndash Low level many available circuits
42
Connection-Oriented and Connectionless Services
Six different types of service
43
Service Primitives (Operations)
Five service primitives for implementing a simple connection-oriented service
A service is formally defined by a set of primitives (operations) available to a user process to access the services
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
8
Goals of Networks for Companies Resource sharing equipment programs data high reliability
ndash replicated data
ndash hardware Saving money
ndash mainframe 10 times faster but 1000 times more expensive than PC
ndash client-server model Scalability
ndash mainframe replace a larger one
ndash client-server model add more servers Communication medium for separated employees
9
Business Applications of Networks (2)
The client-server model involves requests and replies
a Two processes are involved
b A communication network is needed
10
Home Network Applications
bull Access to remote information
bull Person-to-person communication
bull Interactive entertainment
bull Electronic commerce
11
Networks for Peoplendash Access to remote information
bull eg financial shopping customized newspapers on-line digital library WWW
ndash Person-to-person communicationbull email video conference newsgroup
ndash Interactive entertainmentbull VOD interactive movies or TVs game playing
12
Home Network Applications (2)
In peer-to-peer system there are no fixed clients and servers
13
Home Network Applications (3)
Some forms of e-commerce
14
Mobile Network Users
Combinations of wireless networks and mobile computing
mobile-commerce
15
Social Issues
bull Politics
bull Religion
bull Sex
bull Privacy
bull Crime
bull junk mail ill-information Each country has different laws Debate rages
16
Network Hardware
bull Local Area Networks
bull Metropolitan Area Networks
bull Wide Area Networks
bull Wireless Networks
bull Home Networks
bull Internetworks
17
Types of transmission technology
bull Broadcast links
bull Point-to-point links
Network Hardware
18
Network Hardwarendash Broadcast networks
bull single communication channel shared by all machines
bull broadcasting or multicasting (via packets)ndash broadcasting a special code in address field
ndash multicasting reserve one bit to indicate multicasting the remaining n-1address bits can hold a group number Each machine can subscribe to any groups
bull used by localized networks (or satellites)
ndash point-to-point networksbull many hops
bull routing algorithms multiple routs are possible
bull used by large networks
19
Classification of interconnected processors by scale
20
Local Area Networks (LANs)
Two broadcast networks(a) Bus(b) Ring
middot Characterics of LANs (a) privated-owned (b) small size (c) transmission technology (d) topology
middot Ethernets are most popular (up to 10 Gbs)
21
Local Area Networks Characteristics
ndash small size
ndash transmission technologybull single cable
bull 10Mbps ~ 10Gbs
bull 10Gbs 10000000000 bps
ndash topology
bull bus
ndash Ethernet (IEEE 8023) 10 or 100 Mbps (10Gbs)
bull ring
ndash IBM token ring (IEEE 8025) 4 or 16 Mbps
Channel allocation of broadcast networksndash static each machine has an allocated time slot
ndash dynamic
22
Metropolitan Area Networks
A metropolitan area network based on cable TV
23
Wide Area Networks (WANs)
Relation between hosts on LANs and the subnet
middotWANs are point-to-point networks
middotWANs consist of two distinct components transmission lines (copper fiber microwave) and switches (electronics optics)
Store-and-forward or packet-switched subnet
24
Network Topology
25
Subnet (WANs)Subnet (WANs) is consists of two components
ndash transmission lines (circuits channels trunks)bull move bits between machines
ndash switching elementsbull connect transmission lines
bull Router also called packet switching nodes intermediate systems and data switching exchanges
bull Operate in store-and-forward or packet-switched mode
26
Wide Area Networks (2)
A stream of packets from sender to receiver (virtual- circuit)
Routing decisions are made locallymiddot How A makes that decision is called the routing algorithm Will be studied in detail in Chapter 5
917 End
27
Wireless Networks
Categories of wireless networksbull System interconnection
(short-range radio eg Bluetooth)bull Wireless LANs
(80211a 80211b 80211g)bull Wireless WANs
(80216 Cellular telephones Satellites)bull Wireless sensor networks
28
Wireless Networks (2)
(a) Bluetooth configuration(b) Wireless LAN
29
Wireless Networks (3)
(a) Individual mobile computers(b) A flying LAN
30
Home Network Categories
Computers (desktop PC PDA shared peripherals) Entertainment (TV DVD VCR camera stereo MP3) Telecomm (telephone cell phone intercom fax) Appliances (microwave fridge clock furnace airco
light) Telemetry (utility meter smokeburglar alarm babycam)
31
Fundamentally different properties
1 Devices have to be easy to install
2 The network and devices have to be foolproof in
operation
3 Low price is essential
4 The network needs sufficient capacity ( for multimedia
application)
5 The network interface and wiring have to be stable for
many years
6 Security and reliability will be very important
(minimize false alarm or misalarm) Home networks may be wired or wireless
32
Internetworks
bull Internetworks connect networks with different hardware
and softwarebull A collection of interconnected networks is called
an internetwork or internetbull Internet is one specific internetbull Gateways are used to make the connection and to
provide the necessary translation (protocol convertion)
33
Network Software
bull Protocol Hierarchies (Layer structure)bull Design Issues for the Layersbull Connection-Oriented and Connectionless Servicesbull Service Primitivesbull The Relationship of Services to Protocols
34
Network Software
Protocol Hierarchiesndash a series of layers (levels)
ndash lower layer provides service to higher layers
ndash protocol bull an agreement between the communication parties on how
communication is to proceed
ndash Peers bull the corresponding layers on different machines
ndash Network architecture a set of layers and protocols
ndash Protocol stack bull a list of protocols used by a certain system one protocol per
layer
35
Network SoftwareProtocol Hierarchies
Layers protocols and interfaces
Peer
Network Architecture A set of layers and protocols Protocol Stack A list of protocols used by a certain system one protocol per layer
Virtual Communication
PhysicalCommunication
36
Layering
To make things simple modularization
Different layer has different functions
Create layer boundary such that description of services can be small number of interactions across boundary are minimized potential for interface standardized
Different level of abstraction in the handling of data (eg syntax semantics)
Provide appropriate services to upper layer
Use service primitives of lower layer
Network Software
37
Protocol Hierarchies (2)
The philosopher-translator-secretary architecture
38
Protocol Hierarchies (3)
Example information flow supporting virtual communication in layer 5
Message segmentation Encapsulation
39
Design Issues for the Layers
bull Addressing (telephone number e-mail address IP addresshellip)
bull Error Control (error correction codes ARQ HARQhellip)bull Flow Control (feedback-based rate-based)bull Multiplexing (gathering several small messages with the
same destination into a single large message or vice versa Demultiplexing)
bull Routing (directing traffic to the destination)
40
Design Issues for Layers
Identify senders and receivers ndash multiple computers and processes addressing
Data transferndash simplex half-duplex full-duplex communication
ndash of logical channels per connections priorities Error control
ndash error detection
ndash error correction Sequencing of pieces
41
Design Issues for Layers Flow control
ndash feedback from the receiver
ndash agreed upon transmission rate Length of messages
ndash long messages disassemble transmit and reassmeble messages
ndash short messages gather several small messages Multiplexing and Demultiplexing
ndash when expensive to set up a separate connection
ndash needed in physical layer Routing split over two or more layers
ndash High level London -gt France or Germany -gt Rome
ndash Low level many available circuits
42
Connection-Oriented and Connectionless Services
Six different types of service
43
Service Primitives (Operations)
Five service primitives for implementing a simple connection-oriented service
A service is formally defined by a set of primitives (operations) available to a user process to access the services
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
9
Business Applications of Networks (2)
The client-server model involves requests and replies
a Two processes are involved
b A communication network is needed
10
Home Network Applications
bull Access to remote information
bull Person-to-person communication
bull Interactive entertainment
bull Electronic commerce
11
Networks for Peoplendash Access to remote information
bull eg financial shopping customized newspapers on-line digital library WWW
ndash Person-to-person communicationbull email video conference newsgroup
ndash Interactive entertainmentbull VOD interactive movies or TVs game playing
12
Home Network Applications (2)
In peer-to-peer system there are no fixed clients and servers
13
Home Network Applications (3)
Some forms of e-commerce
14
Mobile Network Users
Combinations of wireless networks and mobile computing
mobile-commerce
15
Social Issues
bull Politics
bull Religion
bull Sex
bull Privacy
bull Crime
bull junk mail ill-information Each country has different laws Debate rages
16
Network Hardware
bull Local Area Networks
bull Metropolitan Area Networks
bull Wide Area Networks
bull Wireless Networks
bull Home Networks
bull Internetworks
17
Types of transmission technology
bull Broadcast links
bull Point-to-point links
Network Hardware
18
Network Hardwarendash Broadcast networks
bull single communication channel shared by all machines
bull broadcasting or multicasting (via packets)ndash broadcasting a special code in address field
ndash multicasting reserve one bit to indicate multicasting the remaining n-1address bits can hold a group number Each machine can subscribe to any groups
bull used by localized networks (or satellites)
ndash point-to-point networksbull many hops
bull routing algorithms multiple routs are possible
bull used by large networks
19
Classification of interconnected processors by scale
20
Local Area Networks (LANs)
Two broadcast networks(a) Bus(b) Ring
middot Characterics of LANs (a) privated-owned (b) small size (c) transmission technology (d) topology
middot Ethernets are most popular (up to 10 Gbs)
21
Local Area Networks Characteristics
ndash small size
ndash transmission technologybull single cable
bull 10Mbps ~ 10Gbs
bull 10Gbs 10000000000 bps
ndash topology
bull bus
ndash Ethernet (IEEE 8023) 10 or 100 Mbps (10Gbs)
bull ring
ndash IBM token ring (IEEE 8025) 4 or 16 Mbps
Channel allocation of broadcast networksndash static each machine has an allocated time slot
ndash dynamic
22
Metropolitan Area Networks
A metropolitan area network based on cable TV
23
Wide Area Networks (WANs)
Relation between hosts on LANs and the subnet
middotWANs are point-to-point networks
middotWANs consist of two distinct components transmission lines (copper fiber microwave) and switches (electronics optics)
Store-and-forward or packet-switched subnet
24
Network Topology
25
Subnet (WANs)Subnet (WANs) is consists of two components
ndash transmission lines (circuits channels trunks)bull move bits between machines
ndash switching elementsbull connect transmission lines
bull Router also called packet switching nodes intermediate systems and data switching exchanges
bull Operate in store-and-forward or packet-switched mode
26
Wide Area Networks (2)
A stream of packets from sender to receiver (virtual- circuit)
Routing decisions are made locallymiddot How A makes that decision is called the routing algorithm Will be studied in detail in Chapter 5
917 End
27
Wireless Networks
Categories of wireless networksbull System interconnection
(short-range radio eg Bluetooth)bull Wireless LANs
(80211a 80211b 80211g)bull Wireless WANs
(80216 Cellular telephones Satellites)bull Wireless sensor networks
28
Wireless Networks (2)
(a) Bluetooth configuration(b) Wireless LAN
29
Wireless Networks (3)
(a) Individual mobile computers(b) A flying LAN
30
Home Network Categories
Computers (desktop PC PDA shared peripherals) Entertainment (TV DVD VCR camera stereo MP3) Telecomm (telephone cell phone intercom fax) Appliances (microwave fridge clock furnace airco
light) Telemetry (utility meter smokeburglar alarm babycam)
31
Fundamentally different properties
1 Devices have to be easy to install
2 The network and devices have to be foolproof in
operation
3 Low price is essential
4 The network needs sufficient capacity ( for multimedia
application)
5 The network interface and wiring have to be stable for
many years
6 Security and reliability will be very important
(minimize false alarm or misalarm) Home networks may be wired or wireless
32
Internetworks
bull Internetworks connect networks with different hardware
and softwarebull A collection of interconnected networks is called
an internetwork or internetbull Internet is one specific internetbull Gateways are used to make the connection and to
provide the necessary translation (protocol convertion)
33
Network Software
bull Protocol Hierarchies (Layer structure)bull Design Issues for the Layersbull Connection-Oriented and Connectionless Servicesbull Service Primitivesbull The Relationship of Services to Protocols
34
Network Software
Protocol Hierarchiesndash a series of layers (levels)
ndash lower layer provides service to higher layers
ndash protocol bull an agreement between the communication parties on how
communication is to proceed
ndash Peers bull the corresponding layers on different machines
ndash Network architecture a set of layers and protocols
ndash Protocol stack bull a list of protocols used by a certain system one protocol per
layer
35
Network SoftwareProtocol Hierarchies
Layers protocols and interfaces
Peer
Network Architecture A set of layers and protocols Protocol Stack A list of protocols used by a certain system one protocol per layer
Virtual Communication
PhysicalCommunication
36
Layering
To make things simple modularization
Different layer has different functions
Create layer boundary such that description of services can be small number of interactions across boundary are minimized potential for interface standardized
Different level of abstraction in the handling of data (eg syntax semantics)
Provide appropriate services to upper layer
Use service primitives of lower layer
Network Software
37
Protocol Hierarchies (2)
The philosopher-translator-secretary architecture
38
Protocol Hierarchies (3)
Example information flow supporting virtual communication in layer 5
Message segmentation Encapsulation
39
Design Issues for the Layers
bull Addressing (telephone number e-mail address IP addresshellip)
bull Error Control (error correction codes ARQ HARQhellip)bull Flow Control (feedback-based rate-based)bull Multiplexing (gathering several small messages with the
same destination into a single large message or vice versa Demultiplexing)
bull Routing (directing traffic to the destination)
40
Design Issues for Layers
Identify senders and receivers ndash multiple computers and processes addressing
Data transferndash simplex half-duplex full-duplex communication
ndash of logical channels per connections priorities Error control
ndash error detection
ndash error correction Sequencing of pieces
41
Design Issues for Layers Flow control
ndash feedback from the receiver
ndash agreed upon transmission rate Length of messages
ndash long messages disassemble transmit and reassmeble messages
ndash short messages gather several small messages Multiplexing and Demultiplexing
ndash when expensive to set up a separate connection
ndash needed in physical layer Routing split over two or more layers
ndash High level London -gt France or Germany -gt Rome
ndash Low level many available circuits
42
Connection-Oriented and Connectionless Services
Six different types of service
43
Service Primitives (Operations)
Five service primitives for implementing a simple connection-oriented service
A service is formally defined by a set of primitives (operations) available to a user process to access the services
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
10
Home Network Applications
bull Access to remote information
bull Person-to-person communication
bull Interactive entertainment
bull Electronic commerce
11
Networks for Peoplendash Access to remote information
bull eg financial shopping customized newspapers on-line digital library WWW
ndash Person-to-person communicationbull email video conference newsgroup
ndash Interactive entertainmentbull VOD interactive movies or TVs game playing
12
Home Network Applications (2)
In peer-to-peer system there are no fixed clients and servers
13
Home Network Applications (3)
Some forms of e-commerce
14
Mobile Network Users
Combinations of wireless networks and mobile computing
mobile-commerce
15
Social Issues
bull Politics
bull Religion
bull Sex
bull Privacy
bull Crime
bull junk mail ill-information Each country has different laws Debate rages
16
Network Hardware
bull Local Area Networks
bull Metropolitan Area Networks
bull Wide Area Networks
bull Wireless Networks
bull Home Networks
bull Internetworks
17
Types of transmission technology
bull Broadcast links
bull Point-to-point links
Network Hardware
18
Network Hardwarendash Broadcast networks
bull single communication channel shared by all machines
bull broadcasting or multicasting (via packets)ndash broadcasting a special code in address field
ndash multicasting reserve one bit to indicate multicasting the remaining n-1address bits can hold a group number Each machine can subscribe to any groups
bull used by localized networks (or satellites)
ndash point-to-point networksbull many hops
bull routing algorithms multiple routs are possible
bull used by large networks
19
Classification of interconnected processors by scale
20
Local Area Networks (LANs)
Two broadcast networks(a) Bus(b) Ring
middot Characterics of LANs (a) privated-owned (b) small size (c) transmission technology (d) topology
middot Ethernets are most popular (up to 10 Gbs)
21
Local Area Networks Characteristics
ndash small size
ndash transmission technologybull single cable
bull 10Mbps ~ 10Gbs
bull 10Gbs 10000000000 bps
ndash topology
bull bus
ndash Ethernet (IEEE 8023) 10 or 100 Mbps (10Gbs)
bull ring
ndash IBM token ring (IEEE 8025) 4 or 16 Mbps
Channel allocation of broadcast networksndash static each machine has an allocated time slot
ndash dynamic
22
Metropolitan Area Networks
A metropolitan area network based on cable TV
23
Wide Area Networks (WANs)
Relation between hosts on LANs and the subnet
middotWANs are point-to-point networks
middotWANs consist of two distinct components transmission lines (copper fiber microwave) and switches (electronics optics)
Store-and-forward or packet-switched subnet
24
Network Topology
25
Subnet (WANs)Subnet (WANs) is consists of two components
ndash transmission lines (circuits channels trunks)bull move bits between machines
ndash switching elementsbull connect transmission lines
bull Router also called packet switching nodes intermediate systems and data switching exchanges
bull Operate in store-and-forward or packet-switched mode
26
Wide Area Networks (2)
A stream of packets from sender to receiver (virtual- circuit)
Routing decisions are made locallymiddot How A makes that decision is called the routing algorithm Will be studied in detail in Chapter 5
917 End
27
Wireless Networks
Categories of wireless networksbull System interconnection
(short-range radio eg Bluetooth)bull Wireless LANs
(80211a 80211b 80211g)bull Wireless WANs
(80216 Cellular telephones Satellites)bull Wireless sensor networks
28
Wireless Networks (2)
(a) Bluetooth configuration(b) Wireless LAN
29
Wireless Networks (3)
(a) Individual mobile computers(b) A flying LAN
30
Home Network Categories
Computers (desktop PC PDA shared peripherals) Entertainment (TV DVD VCR camera stereo MP3) Telecomm (telephone cell phone intercom fax) Appliances (microwave fridge clock furnace airco
light) Telemetry (utility meter smokeburglar alarm babycam)
31
Fundamentally different properties
1 Devices have to be easy to install
2 The network and devices have to be foolproof in
operation
3 Low price is essential
4 The network needs sufficient capacity ( for multimedia
application)
5 The network interface and wiring have to be stable for
many years
6 Security and reliability will be very important
(minimize false alarm or misalarm) Home networks may be wired or wireless
32
Internetworks
bull Internetworks connect networks with different hardware
and softwarebull A collection of interconnected networks is called
an internetwork or internetbull Internet is one specific internetbull Gateways are used to make the connection and to
provide the necessary translation (protocol convertion)
33
Network Software
bull Protocol Hierarchies (Layer structure)bull Design Issues for the Layersbull Connection-Oriented and Connectionless Servicesbull Service Primitivesbull The Relationship of Services to Protocols
34
Network Software
Protocol Hierarchiesndash a series of layers (levels)
ndash lower layer provides service to higher layers
ndash protocol bull an agreement between the communication parties on how
communication is to proceed
ndash Peers bull the corresponding layers on different machines
ndash Network architecture a set of layers and protocols
ndash Protocol stack bull a list of protocols used by a certain system one protocol per
layer
35
Network SoftwareProtocol Hierarchies
Layers protocols and interfaces
Peer
Network Architecture A set of layers and protocols Protocol Stack A list of protocols used by a certain system one protocol per layer
Virtual Communication
PhysicalCommunication
36
Layering
To make things simple modularization
Different layer has different functions
Create layer boundary such that description of services can be small number of interactions across boundary are minimized potential for interface standardized
Different level of abstraction in the handling of data (eg syntax semantics)
Provide appropriate services to upper layer
Use service primitives of lower layer
Network Software
37
Protocol Hierarchies (2)
The philosopher-translator-secretary architecture
38
Protocol Hierarchies (3)
Example information flow supporting virtual communication in layer 5
Message segmentation Encapsulation
39
Design Issues for the Layers
bull Addressing (telephone number e-mail address IP addresshellip)
bull Error Control (error correction codes ARQ HARQhellip)bull Flow Control (feedback-based rate-based)bull Multiplexing (gathering several small messages with the
same destination into a single large message or vice versa Demultiplexing)
bull Routing (directing traffic to the destination)
40
Design Issues for Layers
Identify senders and receivers ndash multiple computers and processes addressing
Data transferndash simplex half-duplex full-duplex communication
ndash of logical channels per connections priorities Error control
ndash error detection
ndash error correction Sequencing of pieces
41
Design Issues for Layers Flow control
ndash feedback from the receiver
ndash agreed upon transmission rate Length of messages
ndash long messages disassemble transmit and reassmeble messages
ndash short messages gather several small messages Multiplexing and Demultiplexing
ndash when expensive to set up a separate connection
ndash needed in physical layer Routing split over two or more layers
ndash High level London -gt France or Germany -gt Rome
ndash Low level many available circuits
42
Connection-Oriented and Connectionless Services
Six different types of service
43
Service Primitives (Operations)
Five service primitives for implementing a simple connection-oriented service
A service is formally defined by a set of primitives (operations) available to a user process to access the services
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
11
Networks for Peoplendash Access to remote information
bull eg financial shopping customized newspapers on-line digital library WWW
ndash Person-to-person communicationbull email video conference newsgroup
ndash Interactive entertainmentbull VOD interactive movies or TVs game playing
12
Home Network Applications (2)
In peer-to-peer system there are no fixed clients and servers
13
Home Network Applications (3)
Some forms of e-commerce
14
Mobile Network Users
Combinations of wireless networks and mobile computing
mobile-commerce
15
Social Issues
bull Politics
bull Religion
bull Sex
bull Privacy
bull Crime
bull junk mail ill-information Each country has different laws Debate rages
16
Network Hardware
bull Local Area Networks
bull Metropolitan Area Networks
bull Wide Area Networks
bull Wireless Networks
bull Home Networks
bull Internetworks
17
Types of transmission technology
bull Broadcast links
bull Point-to-point links
Network Hardware
18
Network Hardwarendash Broadcast networks
bull single communication channel shared by all machines
bull broadcasting or multicasting (via packets)ndash broadcasting a special code in address field
ndash multicasting reserve one bit to indicate multicasting the remaining n-1address bits can hold a group number Each machine can subscribe to any groups
bull used by localized networks (or satellites)
ndash point-to-point networksbull many hops
bull routing algorithms multiple routs are possible
bull used by large networks
19
Classification of interconnected processors by scale
20
Local Area Networks (LANs)
Two broadcast networks(a) Bus(b) Ring
middot Characterics of LANs (a) privated-owned (b) small size (c) transmission technology (d) topology
middot Ethernets are most popular (up to 10 Gbs)
21
Local Area Networks Characteristics
ndash small size
ndash transmission technologybull single cable
bull 10Mbps ~ 10Gbs
bull 10Gbs 10000000000 bps
ndash topology
bull bus
ndash Ethernet (IEEE 8023) 10 or 100 Mbps (10Gbs)
bull ring
ndash IBM token ring (IEEE 8025) 4 or 16 Mbps
Channel allocation of broadcast networksndash static each machine has an allocated time slot
ndash dynamic
22
Metropolitan Area Networks
A metropolitan area network based on cable TV
23
Wide Area Networks (WANs)
Relation between hosts on LANs and the subnet
middotWANs are point-to-point networks
middotWANs consist of two distinct components transmission lines (copper fiber microwave) and switches (electronics optics)
Store-and-forward or packet-switched subnet
24
Network Topology
25
Subnet (WANs)Subnet (WANs) is consists of two components
ndash transmission lines (circuits channels trunks)bull move bits between machines
ndash switching elementsbull connect transmission lines
bull Router also called packet switching nodes intermediate systems and data switching exchanges
bull Operate in store-and-forward or packet-switched mode
26
Wide Area Networks (2)
A stream of packets from sender to receiver (virtual- circuit)
Routing decisions are made locallymiddot How A makes that decision is called the routing algorithm Will be studied in detail in Chapter 5
917 End
27
Wireless Networks
Categories of wireless networksbull System interconnection
(short-range radio eg Bluetooth)bull Wireless LANs
(80211a 80211b 80211g)bull Wireless WANs
(80216 Cellular telephones Satellites)bull Wireless sensor networks
28
Wireless Networks (2)
(a) Bluetooth configuration(b) Wireless LAN
29
Wireless Networks (3)
(a) Individual mobile computers(b) A flying LAN
30
Home Network Categories
Computers (desktop PC PDA shared peripherals) Entertainment (TV DVD VCR camera stereo MP3) Telecomm (telephone cell phone intercom fax) Appliances (microwave fridge clock furnace airco
light) Telemetry (utility meter smokeburglar alarm babycam)
31
Fundamentally different properties
1 Devices have to be easy to install
2 The network and devices have to be foolproof in
operation
3 Low price is essential
4 The network needs sufficient capacity ( for multimedia
application)
5 The network interface and wiring have to be stable for
many years
6 Security and reliability will be very important
(minimize false alarm or misalarm) Home networks may be wired or wireless
32
Internetworks
bull Internetworks connect networks with different hardware
and softwarebull A collection of interconnected networks is called
an internetwork or internetbull Internet is one specific internetbull Gateways are used to make the connection and to
provide the necessary translation (protocol convertion)
33
Network Software
bull Protocol Hierarchies (Layer structure)bull Design Issues for the Layersbull Connection-Oriented and Connectionless Servicesbull Service Primitivesbull The Relationship of Services to Protocols
34
Network Software
Protocol Hierarchiesndash a series of layers (levels)
ndash lower layer provides service to higher layers
ndash protocol bull an agreement between the communication parties on how
communication is to proceed
ndash Peers bull the corresponding layers on different machines
ndash Network architecture a set of layers and protocols
ndash Protocol stack bull a list of protocols used by a certain system one protocol per
layer
35
Network SoftwareProtocol Hierarchies
Layers protocols and interfaces
Peer
Network Architecture A set of layers and protocols Protocol Stack A list of protocols used by a certain system one protocol per layer
Virtual Communication
PhysicalCommunication
36
Layering
To make things simple modularization
Different layer has different functions
Create layer boundary such that description of services can be small number of interactions across boundary are minimized potential for interface standardized
Different level of abstraction in the handling of data (eg syntax semantics)
Provide appropriate services to upper layer
Use service primitives of lower layer
Network Software
37
Protocol Hierarchies (2)
The philosopher-translator-secretary architecture
38
Protocol Hierarchies (3)
Example information flow supporting virtual communication in layer 5
Message segmentation Encapsulation
39
Design Issues for the Layers
bull Addressing (telephone number e-mail address IP addresshellip)
bull Error Control (error correction codes ARQ HARQhellip)bull Flow Control (feedback-based rate-based)bull Multiplexing (gathering several small messages with the
same destination into a single large message or vice versa Demultiplexing)
bull Routing (directing traffic to the destination)
40
Design Issues for Layers
Identify senders and receivers ndash multiple computers and processes addressing
Data transferndash simplex half-duplex full-duplex communication
ndash of logical channels per connections priorities Error control
ndash error detection
ndash error correction Sequencing of pieces
41
Design Issues for Layers Flow control
ndash feedback from the receiver
ndash agreed upon transmission rate Length of messages
ndash long messages disassemble transmit and reassmeble messages
ndash short messages gather several small messages Multiplexing and Demultiplexing
ndash when expensive to set up a separate connection
ndash needed in physical layer Routing split over two or more layers
ndash High level London -gt France or Germany -gt Rome
ndash Low level many available circuits
42
Connection-Oriented and Connectionless Services
Six different types of service
43
Service Primitives (Operations)
Five service primitives for implementing a simple connection-oriented service
A service is formally defined by a set of primitives (operations) available to a user process to access the services
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
12
Home Network Applications (2)
In peer-to-peer system there are no fixed clients and servers
13
Home Network Applications (3)
Some forms of e-commerce
14
Mobile Network Users
Combinations of wireless networks and mobile computing
mobile-commerce
15
Social Issues
bull Politics
bull Religion
bull Sex
bull Privacy
bull Crime
bull junk mail ill-information Each country has different laws Debate rages
16
Network Hardware
bull Local Area Networks
bull Metropolitan Area Networks
bull Wide Area Networks
bull Wireless Networks
bull Home Networks
bull Internetworks
17
Types of transmission technology
bull Broadcast links
bull Point-to-point links
Network Hardware
18
Network Hardwarendash Broadcast networks
bull single communication channel shared by all machines
bull broadcasting or multicasting (via packets)ndash broadcasting a special code in address field
ndash multicasting reserve one bit to indicate multicasting the remaining n-1address bits can hold a group number Each machine can subscribe to any groups
bull used by localized networks (or satellites)
ndash point-to-point networksbull many hops
bull routing algorithms multiple routs are possible
bull used by large networks
19
Classification of interconnected processors by scale
20
Local Area Networks (LANs)
Two broadcast networks(a) Bus(b) Ring
middot Characterics of LANs (a) privated-owned (b) small size (c) transmission technology (d) topology
middot Ethernets are most popular (up to 10 Gbs)
21
Local Area Networks Characteristics
ndash small size
ndash transmission technologybull single cable
bull 10Mbps ~ 10Gbs
bull 10Gbs 10000000000 bps
ndash topology
bull bus
ndash Ethernet (IEEE 8023) 10 or 100 Mbps (10Gbs)
bull ring
ndash IBM token ring (IEEE 8025) 4 or 16 Mbps
Channel allocation of broadcast networksndash static each machine has an allocated time slot
ndash dynamic
22
Metropolitan Area Networks
A metropolitan area network based on cable TV
23
Wide Area Networks (WANs)
Relation between hosts on LANs and the subnet
middotWANs are point-to-point networks
middotWANs consist of two distinct components transmission lines (copper fiber microwave) and switches (electronics optics)
Store-and-forward or packet-switched subnet
24
Network Topology
25
Subnet (WANs)Subnet (WANs) is consists of two components
ndash transmission lines (circuits channels trunks)bull move bits between machines
ndash switching elementsbull connect transmission lines
bull Router also called packet switching nodes intermediate systems and data switching exchanges
bull Operate in store-and-forward or packet-switched mode
26
Wide Area Networks (2)
A stream of packets from sender to receiver (virtual- circuit)
Routing decisions are made locallymiddot How A makes that decision is called the routing algorithm Will be studied in detail in Chapter 5
917 End
27
Wireless Networks
Categories of wireless networksbull System interconnection
(short-range radio eg Bluetooth)bull Wireless LANs
(80211a 80211b 80211g)bull Wireless WANs
(80216 Cellular telephones Satellites)bull Wireless sensor networks
28
Wireless Networks (2)
(a) Bluetooth configuration(b) Wireless LAN
29
Wireless Networks (3)
(a) Individual mobile computers(b) A flying LAN
30
Home Network Categories
Computers (desktop PC PDA shared peripherals) Entertainment (TV DVD VCR camera stereo MP3) Telecomm (telephone cell phone intercom fax) Appliances (microwave fridge clock furnace airco
light) Telemetry (utility meter smokeburglar alarm babycam)
31
Fundamentally different properties
1 Devices have to be easy to install
2 The network and devices have to be foolproof in
operation
3 Low price is essential
4 The network needs sufficient capacity ( for multimedia
application)
5 The network interface and wiring have to be stable for
many years
6 Security and reliability will be very important
(minimize false alarm or misalarm) Home networks may be wired or wireless
32
Internetworks
bull Internetworks connect networks with different hardware
and softwarebull A collection of interconnected networks is called
an internetwork or internetbull Internet is one specific internetbull Gateways are used to make the connection and to
provide the necessary translation (protocol convertion)
33
Network Software
bull Protocol Hierarchies (Layer structure)bull Design Issues for the Layersbull Connection-Oriented and Connectionless Servicesbull Service Primitivesbull The Relationship of Services to Protocols
34
Network Software
Protocol Hierarchiesndash a series of layers (levels)
ndash lower layer provides service to higher layers
ndash protocol bull an agreement between the communication parties on how
communication is to proceed
ndash Peers bull the corresponding layers on different machines
ndash Network architecture a set of layers and protocols
ndash Protocol stack bull a list of protocols used by a certain system one protocol per
layer
35
Network SoftwareProtocol Hierarchies
Layers protocols and interfaces
Peer
Network Architecture A set of layers and protocols Protocol Stack A list of protocols used by a certain system one protocol per layer
Virtual Communication
PhysicalCommunication
36
Layering
To make things simple modularization
Different layer has different functions
Create layer boundary such that description of services can be small number of interactions across boundary are minimized potential for interface standardized
Different level of abstraction in the handling of data (eg syntax semantics)
Provide appropriate services to upper layer
Use service primitives of lower layer
Network Software
37
Protocol Hierarchies (2)
The philosopher-translator-secretary architecture
38
Protocol Hierarchies (3)
Example information flow supporting virtual communication in layer 5
Message segmentation Encapsulation
39
Design Issues for the Layers
bull Addressing (telephone number e-mail address IP addresshellip)
bull Error Control (error correction codes ARQ HARQhellip)bull Flow Control (feedback-based rate-based)bull Multiplexing (gathering several small messages with the
same destination into a single large message or vice versa Demultiplexing)
bull Routing (directing traffic to the destination)
40
Design Issues for Layers
Identify senders and receivers ndash multiple computers and processes addressing
Data transferndash simplex half-duplex full-duplex communication
ndash of logical channels per connections priorities Error control
ndash error detection
ndash error correction Sequencing of pieces
41
Design Issues for Layers Flow control
ndash feedback from the receiver
ndash agreed upon transmission rate Length of messages
ndash long messages disassemble transmit and reassmeble messages
ndash short messages gather several small messages Multiplexing and Demultiplexing
ndash when expensive to set up a separate connection
ndash needed in physical layer Routing split over two or more layers
ndash High level London -gt France or Germany -gt Rome
ndash Low level many available circuits
42
Connection-Oriented and Connectionless Services
Six different types of service
43
Service Primitives (Operations)
Five service primitives for implementing a simple connection-oriented service
A service is formally defined by a set of primitives (operations) available to a user process to access the services
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
13
Home Network Applications (3)
Some forms of e-commerce
14
Mobile Network Users
Combinations of wireless networks and mobile computing
mobile-commerce
15
Social Issues
bull Politics
bull Religion
bull Sex
bull Privacy
bull Crime
bull junk mail ill-information Each country has different laws Debate rages
16
Network Hardware
bull Local Area Networks
bull Metropolitan Area Networks
bull Wide Area Networks
bull Wireless Networks
bull Home Networks
bull Internetworks
17
Types of transmission technology
bull Broadcast links
bull Point-to-point links
Network Hardware
18
Network Hardwarendash Broadcast networks
bull single communication channel shared by all machines
bull broadcasting or multicasting (via packets)ndash broadcasting a special code in address field
ndash multicasting reserve one bit to indicate multicasting the remaining n-1address bits can hold a group number Each machine can subscribe to any groups
bull used by localized networks (or satellites)
ndash point-to-point networksbull many hops
bull routing algorithms multiple routs are possible
bull used by large networks
19
Classification of interconnected processors by scale
20
Local Area Networks (LANs)
Two broadcast networks(a) Bus(b) Ring
middot Characterics of LANs (a) privated-owned (b) small size (c) transmission technology (d) topology
middot Ethernets are most popular (up to 10 Gbs)
21
Local Area Networks Characteristics
ndash small size
ndash transmission technologybull single cable
bull 10Mbps ~ 10Gbs
bull 10Gbs 10000000000 bps
ndash topology
bull bus
ndash Ethernet (IEEE 8023) 10 or 100 Mbps (10Gbs)
bull ring
ndash IBM token ring (IEEE 8025) 4 or 16 Mbps
Channel allocation of broadcast networksndash static each machine has an allocated time slot
ndash dynamic
22
Metropolitan Area Networks
A metropolitan area network based on cable TV
23
Wide Area Networks (WANs)
Relation between hosts on LANs and the subnet
middotWANs are point-to-point networks
middotWANs consist of two distinct components transmission lines (copper fiber microwave) and switches (electronics optics)
Store-and-forward or packet-switched subnet
24
Network Topology
25
Subnet (WANs)Subnet (WANs) is consists of two components
ndash transmission lines (circuits channels trunks)bull move bits between machines
ndash switching elementsbull connect transmission lines
bull Router also called packet switching nodes intermediate systems and data switching exchanges
bull Operate in store-and-forward or packet-switched mode
26
Wide Area Networks (2)
A stream of packets from sender to receiver (virtual- circuit)
Routing decisions are made locallymiddot How A makes that decision is called the routing algorithm Will be studied in detail in Chapter 5
917 End
27
Wireless Networks
Categories of wireless networksbull System interconnection
(short-range radio eg Bluetooth)bull Wireless LANs
(80211a 80211b 80211g)bull Wireless WANs
(80216 Cellular telephones Satellites)bull Wireless sensor networks
28
Wireless Networks (2)
(a) Bluetooth configuration(b) Wireless LAN
29
Wireless Networks (3)
(a) Individual mobile computers(b) A flying LAN
30
Home Network Categories
Computers (desktop PC PDA shared peripherals) Entertainment (TV DVD VCR camera stereo MP3) Telecomm (telephone cell phone intercom fax) Appliances (microwave fridge clock furnace airco
light) Telemetry (utility meter smokeburglar alarm babycam)
31
Fundamentally different properties
1 Devices have to be easy to install
2 The network and devices have to be foolproof in
operation
3 Low price is essential
4 The network needs sufficient capacity ( for multimedia
application)
5 The network interface and wiring have to be stable for
many years
6 Security and reliability will be very important
(minimize false alarm or misalarm) Home networks may be wired or wireless
32
Internetworks
bull Internetworks connect networks with different hardware
and softwarebull A collection of interconnected networks is called
an internetwork or internetbull Internet is one specific internetbull Gateways are used to make the connection and to
provide the necessary translation (protocol convertion)
33
Network Software
bull Protocol Hierarchies (Layer structure)bull Design Issues for the Layersbull Connection-Oriented and Connectionless Servicesbull Service Primitivesbull The Relationship of Services to Protocols
34
Network Software
Protocol Hierarchiesndash a series of layers (levels)
ndash lower layer provides service to higher layers
ndash protocol bull an agreement between the communication parties on how
communication is to proceed
ndash Peers bull the corresponding layers on different machines
ndash Network architecture a set of layers and protocols
ndash Protocol stack bull a list of protocols used by a certain system one protocol per
layer
35
Network SoftwareProtocol Hierarchies
Layers protocols and interfaces
Peer
Network Architecture A set of layers and protocols Protocol Stack A list of protocols used by a certain system one protocol per layer
Virtual Communication
PhysicalCommunication
36
Layering
To make things simple modularization
Different layer has different functions
Create layer boundary such that description of services can be small number of interactions across boundary are minimized potential for interface standardized
Different level of abstraction in the handling of data (eg syntax semantics)
Provide appropriate services to upper layer
Use service primitives of lower layer
Network Software
37
Protocol Hierarchies (2)
The philosopher-translator-secretary architecture
38
Protocol Hierarchies (3)
Example information flow supporting virtual communication in layer 5
Message segmentation Encapsulation
39
Design Issues for the Layers
bull Addressing (telephone number e-mail address IP addresshellip)
bull Error Control (error correction codes ARQ HARQhellip)bull Flow Control (feedback-based rate-based)bull Multiplexing (gathering several small messages with the
same destination into a single large message or vice versa Demultiplexing)
bull Routing (directing traffic to the destination)
40
Design Issues for Layers
Identify senders and receivers ndash multiple computers and processes addressing
Data transferndash simplex half-duplex full-duplex communication
ndash of logical channels per connections priorities Error control
ndash error detection
ndash error correction Sequencing of pieces
41
Design Issues for Layers Flow control
ndash feedback from the receiver
ndash agreed upon transmission rate Length of messages
ndash long messages disassemble transmit and reassmeble messages
ndash short messages gather several small messages Multiplexing and Demultiplexing
ndash when expensive to set up a separate connection
ndash needed in physical layer Routing split over two or more layers
ndash High level London -gt France or Germany -gt Rome
ndash Low level many available circuits
42
Connection-Oriented and Connectionless Services
Six different types of service
43
Service Primitives (Operations)
Five service primitives for implementing a simple connection-oriented service
A service is formally defined by a set of primitives (operations) available to a user process to access the services
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
14
Mobile Network Users
Combinations of wireless networks and mobile computing
mobile-commerce
15
Social Issues
bull Politics
bull Religion
bull Sex
bull Privacy
bull Crime
bull junk mail ill-information Each country has different laws Debate rages
16
Network Hardware
bull Local Area Networks
bull Metropolitan Area Networks
bull Wide Area Networks
bull Wireless Networks
bull Home Networks
bull Internetworks
17
Types of transmission technology
bull Broadcast links
bull Point-to-point links
Network Hardware
18
Network Hardwarendash Broadcast networks
bull single communication channel shared by all machines
bull broadcasting or multicasting (via packets)ndash broadcasting a special code in address field
ndash multicasting reserve one bit to indicate multicasting the remaining n-1address bits can hold a group number Each machine can subscribe to any groups
bull used by localized networks (or satellites)
ndash point-to-point networksbull many hops
bull routing algorithms multiple routs are possible
bull used by large networks
19
Classification of interconnected processors by scale
20
Local Area Networks (LANs)
Two broadcast networks(a) Bus(b) Ring
middot Characterics of LANs (a) privated-owned (b) small size (c) transmission technology (d) topology
middot Ethernets are most popular (up to 10 Gbs)
21
Local Area Networks Characteristics
ndash small size
ndash transmission technologybull single cable
bull 10Mbps ~ 10Gbs
bull 10Gbs 10000000000 bps
ndash topology
bull bus
ndash Ethernet (IEEE 8023) 10 or 100 Mbps (10Gbs)
bull ring
ndash IBM token ring (IEEE 8025) 4 or 16 Mbps
Channel allocation of broadcast networksndash static each machine has an allocated time slot
ndash dynamic
22
Metropolitan Area Networks
A metropolitan area network based on cable TV
23
Wide Area Networks (WANs)
Relation between hosts on LANs and the subnet
middotWANs are point-to-point networks
middotWANs consist of two distinct components transmission lines (copper fiber microwave) and switches (electronics optics)
Store-and-forward or packet-switched subnet
24
Network Topology
25
Subnet (WANs)Subnet (WANs) is consists of two components
ndash transmission lines (circuits channels trunks)bull move bits between machines
ndash switching elementsbull connect transmission lines
bull Router also called packet switching nodes intermediate systems and data switching exchanges
bull Operate in store-and-forward or packet-switched mode
26
Wide Area Networks (2)
A stream of packets from sender to receiver (virtual- circuit)
Routing decisions are made locallymiddot How A makes that decision is called the routing algorithm Will be studied in detail in Chapter 5
917 End
27
Wireless Networks
Categories of wireless networksbull System interconnection
(short-range radio eg Bluetooth)bull Wireless LANs
(80211a 80211b 80211g)bull Wireless WANs
(80216 Cellular telephones Satellites)bull Wireless sensor networks
28
Wireless Networks (2)
(a) Bluetooth configuration(b) Wireless LAN
29
Wireless Networks (3)
(a) Individual mobile computers(b) A flying LAN
30
Home Network Categories
Computers (desktop PC PDA shared peripherals) Entertainment (TV DVD VCR camera stereo MP3) Telecomm (telephone cell phone intercom fax) Appliances (microwave fridge clock furnace airco
light) Telemetry (utility meter smokeburglar alarm babycam)
31
Fundamentally different properties
1 Devices have to be easy to install
2 The network and devices have to be foolproof in
operation
3 Low price is essential
4 The network needs sufficient capacity ( for multimedia
application)
5 The network interface and wiring have to be stable for
many years
6 Security and reliability will be very important
(minimize false alarm or misalarm) Home networks may be wired or wireless
32
Internetworks
bull Internetworks connect networks with different hardware
and softwarebull A collection of interconnected networks is called
an internetwork or internetbull Internet is one specific internetbull Gateways are used to make the connection and to
provide the necessary translation (protocol convertion)
33
Network Software
bull Protocol Hierarchies (Layer structure)bull Design Issues for the Layersbull Connection-Oriented and Connectionless Servicesbull Service Primitivesbull The Relationship of Services to Protocols
34
Network Software
Protocol Hierarchiesndash a series of layers (levels)
ndash lower layer provides service to higher layers
ndash protocol bull an agreement between the communication parties on how
communication is to proceed
ndash Peers bull the corresponding layers on different machines
ndash Network architecture a set of layers and protocols
ndash Protocol stack bull a list of protocols used by a certain system one protocol per
layer
35
Network SoftwareProtocol Hierarchies
Layers protocols and interfaces
Peer
Network Architecture A set of layers and protocols Protocol Stack A list of protocols used by a certain system one protocol per layer
Virtual Communication
PhysicalCommunication
36
Layering
To make things simple modularization
Different layer has different functions
Create layer boundary such that description of services can be small number of interactions across boundary are minimized potential for interface standardized
Different level of abstraction in the handling of data (eg syntax semantics)
Provide appropriate services to upper layer
Use service primitives of lower layer
Network Software
37
Protocol Hierarchies (2)
The philosopher-translator-secretary architecture
38
Protocol Hierarchies (3)
Example information flow supporting virtual communication in layer 5
Message segmentation Encapsulation
39
Design Issues for the Layers
bull Addressing (telephone number e-mail address IP addresshellip)
bull Error Control (error correction codes ARQ HARQhellip)bull Flow Control (feedback-based rate-based)bull Multiplexing (gathering several small messages with the
same destination into a single large message or vice versa Demultiplexing)
bull Routing (directing traffic to the destination)
40
Design Issues for Layers
Identify senders and receivers ndash multiple computers and processes addressing
Data transferndash simplex half-duplex full-duplex communication
ndash of logical channels per connections priorities Error control
ndash error detection
ndash error correction Sequencing of pieces
41
Design Issues for Layers Flow control
ndash feedback from the receiver
ndash agreed upon transmission rate Length of messages
ndash long messages disassemble transmit and reassmeble messages
ndash short messages gather several small messages Multiplexing and Demultiplexing
ndash when expensive to set up a separate connection
ndash needed in physical layer Routing split over two or more layers
ndash High level London -gt France or Germany -gt Rome
ndash Low level many available circuits
42
Connection-Oriented and Connectionless Services
Six different types of service
43
Service Primitives (Operations)
Five service primitives for implementing a simple connection-oriented service
A service is formally defined by a set of primitives (operations) available to a user process to access the services
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
15
Social Issues
bull Politics
bull Religion
bull Sex
bull Privacy
bull Crime
bull junk mail ill-information Each country has different laws Debate rages
16
Network Hardware
bull Local Area Networks
bull Metropolitan Area Networks
bull Wide Area Networks
bull Wireless Networks
bull Home Networks
bull Internetworks
17
Types of transmission technology
bull Broadcast links
bull Point-to-point links
Network Hardware
18
Network Hardwarendash Broadcast networks
bull single communication channel shared by all machines
bull broadcasting or multicasting (via packets)ndash broadcasting a special code in address field
ndash multicasting reserve one bit to indicate multicasting the remaining n-1address bits can hold a group number Each machine can subscribe to any groups
bull used by localized networks (or satellites)
ndash point-to-point networksbull many hops
bull routing algorithms multiple routs are possible
bull used by large networks
19
Classification of interconnected processors by scale
20
Local Area Networks (LANs)
Two broadcast networks(a) Bus(b) Ring
middot Characterics of LANs (a) privated-owned (b) small size (c) transmission technology (d) topology
middot Ethernets are most popular (up to 10 Gbs)
21
Local Area Networks Characteristics
ndash small size
ndash transmission technologybull single cable
bull 10Mbps ~ 10Gbs
bull 10Gbs 10000000000 bps
ndash topology
bull bus
ndash Ethernet (IEEE 8023) 10 or 100 Mbps (10Gbs)
bull ring
ndash IBM token ring (IEEE 8025) 4 or 16 Mbps
Channel allocation of broadcast networksndash static each machine has an allocated time slot
ndash dynamic
22
Metropolitan Area Networks
A metropolitan area network based on cable TV
23
Wide Area Networks (WANs)
Relation between hosts on LANs and the subnet
middotWANs are point-to-point networks
middotWANs consist of two distinct components transmission lines (copper fiber microwave) and switches (electronics optics)
Store-and-forward or packet-switched subnet
24
Network Topology
25
Subnet (WANs)Subnet (WANs) is consists of two components
ndash transmission lines (circuits channels trunks)bull move bits between machines
ndash switching elementsbull connect transmission lines
bull Router also called packet switching nodes intermediate systems and data switching exchanges
bull Operate in store-and-forward or packet-switched mode
26
Wide Area Networks (2)
A stream of packets from sender to receiver (virtual- circuit)
Routing decisions are made locallymiddot How A makes that decision is called the routing algorithm Will be studied in detail in Chapter 5
917 End
27
Wireless Networks
Categories of wireless networksbull System interconnection
(short-range radio eg Bluetooth)bull Wireless LANs
(80211a 80211b 80211g)bull Wireless WANs
(80216 Cellular telephones Satellites)bull Wireless sensor networks
28
Wireless Networks (2)
(a) Bluetooth configuration(b) Wireless LAN
29
Wireless Networks (3)
(a) Individual mobile computers(b) A flying LAN
30
Home Network Categories
Computers (desktop PC PDA shared peripherals) Entertainment (TV DVD VCR camera stereo MP3) Telecomm (telephone cell phone intercom fax) Appliances (microwave fridge clock furnace airco
light) Telemetry (utility meter smokeburglar alarm babycam)
31
Fundamentally different properties
1 Devices have to be easy to install
2 The network and devices have to be foolproof in
operation
3 Low price is essential
4 The network needs sufficient capacity ( for multimedia
application)
5 The network interface and wiring have to be stable for
many years
6 Security and reliability will be very important
(minimize false alarm or misalarm) Home networks may be wired or wireless
32
Internetworks
bull Internetworks connect networks with different hardware
and softwarebull A collection of interconnected networks is called
an internetwork or internetbull Internet is one specific internetbull Gateways are used to make the connection and to
provide the necessary translation (protocol convertion)
33
Network Software
bull Protocol Hierarchies (Layer structure)bull Design Issues for the Layersbull Connection-Oriented and Connectionless Servicesbull Service Primitivesbull The Relationship of Services to Protocols
34
Network Software
Protocol Hierarchiesndash a series of layers (levels)
ndash lower layer provides service to higher layers
ndash protocol bull an agreement between the communication parties on how
communication is to proceed
ndash Peers bull the corresponding layers on different machines
ndash Network architecture a set of layers and protocols
ndash Protocol stack bull a list of protocols used by a certain system one protocol per
layer
35
Network SoftwareProtocol Hierarchies
Layers protocols and interfaces
Peer
Network Architecture A set of layers and protocols Protocol Stack A list of protocols used by a certain system one protocol per layer
Virtual Communication
PhysicalCommunication
36
Layering
To make things simple modularization
Different layer has different functions
Create layer boundary such that description of services can be small number of interactions across boundary are minimized potential for interface standardized
Different level of abstraction in the handling of data (eg syntax semantics)
Provide appropriate services to upper layer
Use service primitives of lower layer
Network Software
37
Protocol Hierarchies (2)
The philosopher-translator-secretary architecture
38
Protocol Hierarchies (3)
Example information flow supporting virtual communication in layer 5
Message segmentation Encapsulation
39
Design Issues for the Layers
bull Addressing (telephone number e-mail address IP addresshellip)
bull Error Control (error correction codes ARQ HARQhellip)bull Flow Control (feedback-based rate-based)bull Multiplexing (gathering several small messages with the
same destination into a single large message or vice versa Demultiplexing)
bull Routing (directing traffic to the destination)
40
Design Issues for Layers
Identify senders and receivers ndash multiple computers and processes addressing
Data transferndash simplex half-duplex full-duplex communication
ndash of logical channels per connections priorities Error control
ndash error detection
ndash error correction Sequencing of pieces
41
Design Issues for Layers Flow control
ndash feedback from the receiver
ndash agreed upon transmission rate Length of messages
ndash long messages disassemble transmit and reassmeble messages
ndash short messages gather several small messages Multiplexing and Demultiplexing
ndash when expensive to set up a separate connection
ndash needed in physical layer Routing split over two or more layers
ndash High level London -gt France or Germany -gt Rome
ndash Low level many available circuits
42
Connection-Oriented and Connectionless Services
Six different types of service
43
Service Primitives (Operations)
Five service primitives for implementing a simple connection-oriented service
A service is formally defined by a set of primitives (operations) available to a user process to access the services
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
16
Network Hardware
bull Local Area Networks
bull Metropolitan Area Networks
bull Wide Area Networks
bull Wireless Networks
bull Home Networks
bull Internetworks
17
Types of transmission technology
bull Broadcast links
bull Point-to-point links
Network Hardware
18
Network Hardwarendash Broadcast networks
bull single communication channel shared by all machines
bull broadcasting or multicasting (via packets)ndash broadcasting a special code in address field
ndash multicasting reserve one bit to indicate multicasting the remaining n-1address bits can hold a group number Each machine can subscribe to any groups
bull used by localized networks (or satellites)
ndash point-to-point networksbull many hops
bull routing algorithms multiple routs are possible
bull used by large networks
19
Classification of interconnected processors by scale
20
Local Area Networks (LANs)
Two broadcast networks(a) Bus(b) Ring
middot Characterics of LANs (a) privated-owned (b) small size (c) transmission technology (d) topology
middot Ethernets are most popular (up to 10 Gbs)
21
Local Area Networks Characteristics
ndash small size
ndash transmission technologybull single cable
bull 10Mbps ~ 10Gbs
bull 10Gbs 10000000000 bps
ndash topology
bull bus
ndash Ethernet (IEEE 8023) 10 or 100 Mbps (10Gbs)
bull ring
ndash IBM token ring (IEEE 8025) 4 or 16 Mbps
Channel allocation of broadcast networksndash static each machine has an allocated time slot
ndash dynamic
22
Metropolitan Area Networks
A metropolitan area network based on cable TV
23
Wide Area Networks (WANs)
Relation between hosts on LANs and the subnet
middotWANs are point-to-point networks
middotWANs consist of two distinct components transmission lines (copper fiber microwave) and switches (electronics optics)
Store-and-forward or packet-switched subnet
24
Network Topology
25
Subnet (WANs)Subnet (WANs) is consists of two components
ndash transmission lines (circuits channels trunks)bull move bits between machines
ndash switching elementsbull connect transmission lines
bull Router also called packet switching nodes intermediate systems and data switching exchanges
bull Operate in store-and-forward or packet-switched mode
26
Wide Area Networks (2)
A stream of packets from sender to receiver (virtual- circuit)
Routing decisions are made locallymiddot How A makes that decision is called the routing algorithm Will be studied in detail in Chapter 5
917 End
27
Wireless Networks
Categories of wireless networksbull System interconnection
(short-range radio eg Bluetooth)bull Wireless LANs
(80211a 80211b 80211g)bull Wireless WANs
(80216 Cellular telephones Satellites)bull Wireless sensor networks
28
Wireless Networks (2)
(a) Bluetooth configuration(b) Wireless LAN
29
Wireless Networks (3)
(a) Individual mobile computers(b) A flying LAN
30
Home Network Categories
Computers (desktop PC PDA shared peripherals) Entertainment (TV DVD VCR camera stereo MP3) Telecomm (telephone cell phone intercom fax) Appliances (microwave fridge clock furnace airco
light) Telemetry (utility meter smokeburglar alarm babycam)
31
Fundamentally different properties
1 Devices have to be easy to install
2 The network and devices have to be foolproof in
operation
3 Low price is essential
4 The network needs sufficient capacity ( for multimedia
application)
5 The network interface and wiring have to be stable for
many years
6 Security and reliability will be very important
(minimize false alarm or misalarm) Home networks may be wired or wireless
32
Internetworks
bull Internetworks connect networks with different hardware
and softwarebull A collection of interconnected networks is called
an internetwork or internetbull Internet is one specific internetbull Gateways are used to make the connection and to
provide the necessary translation (protocol convertion)
33
Network Software
bull Protocol Hierarchies (Layer structure)bull Design Issues for the Layersbull Connection-Oriented and Connectionless Servicesbull Service Primitivesbull The Relationship of Services to Protocols
34
Network Software
Protocol Hierarchiesndash a series of layers (levels)
ndash lower layer provides service to higher layers
ndash protocol bull an agreement between the communication parties on how
communication is to proceed
ndash Peers bull the corresponding layers on different machines
ndash Network architecture a set of layers and protocols
ndash Protocol stack bull a list of protocols used by a certain system one protocol per
layer
35
Network SoftwareProtocol Hierarchies
Layers protocols and interfaces
Peer
Network Architecture A set of layers and protocols Protocol Stack A list of protocols used by a certain system one protocol per layer
Virtual Communication
PhysicalCommunication
36
Layering
To make things simple modularization
Different layer has different functions
Create layer boundary such that description of services can be small number of interactions across boundary are minimized potential for interface standardized
Different level of abstraction in the handling of data (eg syntax semantics)
Provide appropriate services to upper layer
Use service primitives of lower layer
Network Software
37
Protocol Hierarchies (2)
The philosopher-translator-secretary architecture
38
Protocol Hierarchies (3)
Example information flow supporting virtual communication in layer 5
Message segmentation Encapsulation
39
Design Issues for the Layers
bull Addressing (telephone number e-mail address IP addresshellip)
bull Error Control (error correction codes ARQ HARQhellip)bull Flow Control (feedback-based rate-based)bull Multiplexing (gathering several small messages with the
same destination into a single large message or vice versa Demultiplexing)
bull Routing (directing traffic to the destination)
40
Design Issues for Layers
Identify senders and receivers ndash multiple computers and processes addressing
Data transferndash simplex half-duplex full-duplex communication
ndash of logical channels per connections priorities Error control
ndash error detection
ndash error correction Sequencing of pieces
41
Design Issues for Layers Flow control
ndash feedback from the receiver
ndash agreed upon transmission rate Length of messages
ndash long messages disassemble transmit and reassmeble messages
ndash short messages gather several small messages Multiplexing and Demultiplexing
ndash when expensive to set up a separate connection
ndash needed in physical layer Routing split over two or more layers
ndash High level London -gt France or Germany -gt Rome
ndash Low level many available circuits
42
Connection-Oriented and Connectionless Services
Six different types of service
43
Service Primitives (Operations)
Five service primitives for implementing a simple connection-oriented service
A service is formally defined by a set of primitives (operations) available to a user process to access the services
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
17
Types of transmission technology
bull Broadcast links
bull Point-to-point links
Network Hardware
18
Network Hardwarendash Broadcast networks
bull single communication channel shared by all machines
bull broadcasting or multicasting (via packets)ndash broadcasting a special code in address field
ndash multicasting reserve one bit to indicate multicasting the remaining n-1address bits can hold a group number Each machine can subscribe to any groups
bull used by localized networks (or satellites)
ndash point-to-point networksbull many hops
bull routing algorithms multiple routs are possible
bull used by large networks
19
Classification of interconnected processors by scale
20
Local Area Networks (LANs)
Two broadcast networks(a) Bus(b) Ring
middot Characterics of LANs (a) privated-owned (b) small size (c) transmission technology (d) topology
middot Ethernets are most popular (up to 10 Gbs)
21
Local Area Networks Characteristics
ndash small size
ndash transmission technologybull single cable
bull 10Mbps ~ 10Gbs
bull 10Gbs 10000000000 bps
ndash topology
bull bus
ndash Ethernet (IEEE 8023) 10 or 100 Mbps (10Gbs)
bull ring
ndash IBM token ring (IEEE 8025) 4 or 16 Mbps
Channel allocation of broadcast networksndash static each machine has an allocated time slot
ndash dynamic
22
Metropolitan Area Networks
A metropolitan area network based on cable TV
23
Wide Area Networks (WANs)
Relation between hosts on LANs and the subnet
middotWANs are point-to-point networks
middotWANs consist of two distinct components transmission lines (copper fiber microwave) and switches (electronics optics)
Store-and-forward or packet-switched subnet
24
Network Topology
25
Subnet (WANs)Subnet (WANs) is consists of two components
ndash transmission lines (circuits channels trunks)bull move bits between machines
ndash switching elementsbull connect transmission lines
bull Router also called packet switching nodes intermediate systems and data switching exchanges
bull Operate in store-and-forward or packet-switched mode
26
Wide Area Networks (2)
A stream of packets from sender to receiver (virtual- circuit)
Routing decisions are made locallymiddot How A makes that decision is called the routing algorithm Will be studied in detail in Chapter 5
917 End
27
Wireless Networks
Categories of wireless networksbull System interconnection
(short-range radio eg Bluetooth)bull Wireless LANs
(80211a 80211b 80211g)bull Wireless WANs
(80216 Cellular telephones Satellites)bull Wireless sensor networks
28
Wireless Networks (2)
(a) Bluetooth configuration(b) Wireless LAN
29
Wireless Networks (3)
(a) Individual mobile computers(b) A flying LAN
30
Home Network Categories
Computers (desktop PC PDA shared peripherals) Entertainment (TV DVD VCR camera stereo MP3) Telecomm (telephone cell phone intercom fax) Appliances (microwave fridge clock furnace airco
light) Telemetry (utility meter smokeburglar alarm babycam)
31
Fundamentally different properties
1 Devices have to be easy to install
2 The network and devices have to be foolproof in
operation
3 Low price is essential
4 The network needs sufficient capacity ( for multimedia
application)
5 The network interface and wiring have to be stable for
many years
6 Security and reliability will be very important
(minimize false alarm or misalarm) Home networks may be wired or wireless
32
Internetworks
bull Internetworks connect networks with different hardware
and softwarebull A collection of interconnected networks is called
an internetwork or internetbull Internet is one specific internetbull Gateways are used to make the connection and to
provide the necessary translation (protocol convertion)
33
Network Software
bull Protocol Hierarchies (Layer structure)bull Design Issues for the Layersbull Connection-Oriented and Connectionless Servicesbull Service Primitivesbull The Relationship of Services to Protocols
34
Network Software
Protocol Hierarchiesndash a series of layers (levels)
ndash lower layer provides service to higher layers
ndash protocol bull an agreement between the communication parties on how
communication is to proceed
ndash Peers bull the corresponding layers on different machines
ndash Network architecture a set of layers and protocols
ndash Protocol stack bull a list of protocols used by a certain system one protocol per
layer
35
Network SoftwareProtocol Hierarchies
Layers protocols and interfaces
Peer
Network Architecture A set of layers and protocols Protocol Stack A list of protocols used by a certain system one protocol per layer
Virtual Communication
PhysicalCommunication
36
Layering
To make things simple modularization
Different layer has different functions
Create layer boundary such that description of services can be small number of interactions across boundary are minimized potential for interface standardized
Different level of abstraction in the handling of data (eg syntax semantics)
Provide appropriate services to upper layer
Use service primitives of lower layer
Network Software
37
Protocol Hierarchies (2)
The philosopher-translator-secretary architecture
38
Protocol Hierarchies (3)
Example information flow supporting virtual communication in layer 5
Message segmentation Encapsulation
39
Design Issues for the Layers
bull Addressing (telephone number e-mail address IP addresshellip)
bull Error Control (error correction codes ARQ HARQhellip)bull Flow Control (feedback-based rate-based)bull Multiplexing (gathering several small messages with the
same destination into a single large message or vice versa Demultiplexing)
bull Routing (directing traffic to the destination)
40
Design Issues for Layers
Identify senders and receivers ndash multiple computers and processes addressing
Data transferndash simplex half-duplex full-duplex communication
ndash of logical channels per connections priorities Error control
ndash error detection
ndash error correction Sequencing of pieces
41
Design Issues for Layers Flow control
ndash feedback from the receiver
ndash agreed upon transmission rate Length of messages
ndash long messages disassemble transmit and reassmeble messages
ndash short messages gather several small messages Multiplexing and Demultiplexing
ndash when expensive to set up a separate connection
ndash needed in physical layer Routing split over two or more layers
ndash High level London -gt France or Germany -gt Rome
ndash Low level many available circuits
42
Connection-Oriented and Connectionless Services
Six different types of service
43
Service Primitives (Operations)
Five service primitives for implementing a simple connection-oriented service
A service is formally defined by a set of primitives (operations) available to a user process to access the services
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
18
Network Hardwarendash Broadcast networks
bull single communication channel shared by all machines
bull broadcasting or multicasting (via packets)ndash broadcasting a special code in address field
ndash multicasting reserve one bit to indicate multicasting the remaining n-1address bits can hold a group number Each machine can subscribe to any groups
bull used by localized networks (or satellites)
ndash point-to-point networksbull many hops
bull routing algorithms multiple routs are possible
bull used by large networks
19
Classification of interconnected processors by scale
20
Local Area Networks (LANs)
Two broadcast networks(a) Bus(b) Ring
middot Characterics of LANs (a) privated-owned (b) small size (c) transmission technology (d) topology
middot Ethernets are most popular (up to 10 Gbs)
21
Local Area Networks Characteristics
ndash small size
ndash transmission technologybull single cable
bull 10Mbps ~ 10Gbs
bull 10Gbs 10000000000 bps
ndash topology
bull bus
ndash Ethernet (IEEE 8023) 10 or 100 Mbps (10Gbs)
bull ring
ndash IBM token ring (IEEE 8025) 4 or 16 Mbps
Channel allocation of broadcast networksndash static each machine has an allocated time slot
ndash dynamic
22
Metropolitan Area Networks
A metropolitan area network based on cable TV
23
Wide Area Networks (WANs)
Relation between hosts on LANs and the subnet
middotWANs are point-to-point networks
middotWANs consist of two distinct components transmission lines (copper fiber microwave) and switches (electronics optics)
Store-and-forward or packet-switched subnet
24
Network Topology
25
Subnet (WANs)Subnet (WANs) is consists of two components
ndash transmission lines (circuits channels trunks)bull move bits between machines
ndash switching elementsbull connect transmission lines
bull Router also called packet switching nodes intermediate systems and data switching exchanges
bull Operate in store-and-forward or packet-switched mode
26
Wide Area Networks (2)
A stream of packets from sender to receiver (virtual- circuit)
Routing decisions are made locallymiddot How A makes that decision is called the routing algorithm Will be studied in detail in Chapter 5
917 End
27
Wireless Networks
Categories of wireless networksbull System interconnection
(short-range radio eg Bluetooth)bull Wireless LANs
(80211a 80211b 80211g)bull Wireless WANs
(80216 Cellular telephones Satellites)bull Wireless sensor networks
28
Wireless Networks (2)
(a) Bluetooth configuration(b) Wireless LAN
29
Wireless Networks (3)
(a) Individual mobile computers(b) A flying LAN
30
Home Network Categories
Computers (desktop PC PDA shared peripherals) Entertainment (TV DVD VCR camera stereo MP3) Telecomm (telephone cell phone intercom fax) Appliances (microwave fridge clock furnace airco
light) Telemetry (utility meter smokeburglar alarm babycam)
31
Fundamentally different properties
1 Devices have to be easy to install
2 The network and devices have to be foolproof in
operation
3 Low price is essential
4 The network needs sufficient capacity ( for multimedia
application)
5 The network interface and wiring have to be stable for
many years
6 Security and reliability will be very important
(minimize false alarm or misalarm) Home networks may be wired or wireless
32
Internetworks
bull Internetworks connect networks with different hardware
and softwarebull A collection of interconnected networks is called
an internetwork or internetbull Internet is one specific internetbull Gateways are used to make the connection and to
provide the necessary translation (protocol convertion)
33
Network Software
bull Protocol Hierarchies (Layer structure)bull Design Issues for the Layersbull Connection-Oriented and Connectionless Servicesbull Service Primitivesbull The Relationship of Services to Protocols
34
Network Software
Protocol Hierarchiesndash a series of layers (levels)
ndash lower layer provides service to higher layers
ndash protocol bull an agreement between the communication parties on how
communication is to proceed
ndash Peers bull the corresponding layers on different machines
ndash Network architecture a set of layers and protocols
ndash Protocol stack bull a list of protocols used by a certain system one protocol per
layer
35
Network SoftwareProtocol Hierarchies
Layers protocols and interfaces
Peer
Network Architecture A set of layers and protocols Protocol Stack A list of protocols used by a certain system one protocol per layer
Virtual Communication
PhysicalCommunication
36
Layering
To make things simple modularization
Different layer has different functions
Create layer boundary such that description of services can be small number of interactions across boundary are minimized potential for interface standardized
Different level of abstraction in the handling of data (eg syntax semantics)
Provide appropriate services to upper layer
Use service primitives of lower layer
Network Software
37
Protocol Hierarchies (2)
The philosopher-translator-secretary architecture
38
Protocol Hierarchies (3)
Example information flow supporting virtual communication in layer 5
Message segmentation Encapsulation
39
Design Issues for the Layers
bull Addressing (telephone number e-mail address IP addresshellip)
bull Error Control (error correction codes ARQ HARQhellip)bull Flow Control (feedback-based rate-based)bull Multiplexing (gathering several small messages with the
same destination into a single large message or vice versa Demultiplexing)
bull Routing (directing traffic to the destination)
40
Design Issues for Layers
Identify senders and receivers ndash multiple computers and processes addressing
Data transferndash simplex half-duplex full-duplex communication
ndash of logical channels per connections priorities Error control
ndash error detection
ndash error correction Sequencing of pieces
41
Design Issues for Layers Flow control
ndash feedback from the receiver
ndash agreed upon transmission rate Length of messages
ndash long messages disassemble transmit and reassmeble messages
ndash short messages gather several small messages Multiplexing and Demultiplexing
ndash when expensive to set up a separate connection
ndash needed in physical layer Routing split over two or more layers
ndash High level London -gt France or Germany -gt Rome
ndash Low level many available circuits
42
Connection-Oriented and Connectionless Services
Six different types of service
43
Service Primitives (Operations)
Five service primitives for implementing a simple connection-oriented service
A service is formally defined by a set of primitives (operations) available to a user process to access the services
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
19
Classification of interconnected processors by scale
20
Local Area Networks (LANs)
Two broadcast networks(a) Bus(b) Ring
middot Characterics of LANs (a) privated-owned (b) small size (c) transmission technology (d) topology
middot Ethernets are most popular (up to 10 Gbs)
21
Local Area Networks Characteristics
ndash small size
ndash transmission technologybull single cable
bull 10Mbps ~ 10Gbs
bull 10Gbs 10000000000 bps
ndash topology
bull bus
ndash Ethernet (IEEE 8023) 10 or 100 Mbps (10Gbs)
bull ring
ndash IBM token ring (IEEE 8025) 4 or 16 Mbps
Channel allocation of broadcast networksndash static each machine has an allocated time slot
ndash dynamic
22
Metropolitan Area Networks
A metropolitan area network based on cable TV
23
Wide Area Networks (WANs)
Relation between hosts on LANs and the subnet
middotWANs are point-to-point networks
middotWANs consist of two distinct components transmission lines (copper fiber microwave) and switches (electronics optics)
Store-and-forward or packet-switched subnet
24
Network Topology
25
Subnet (WANs)Subnet (WANs) is consists of two components
ndash transmission lines (circuits channels trunks)bull move bits between machines
ndash switching elementsbull connect transmission lines
bull Router also called packet switching nodes intermediate systems and data switching exchanges
bull Operate in store-and-forward or packet-switched mode
26
Wide Area Networks (2)
A stream of packets from sender to receiver (virtual- circuit)
Routing decisions are made locallymiddot How A makes that decision is called the routing algorithm Will be studied in detail in Chapter 5
917 End
27
Wireless Networks
Categories of wireless networksbull System interconnection
(short-range radio eg Bluetooth)bull Wireless LANs
(80211a 80211b 80211g)bull Wireless WANs
(80216 Cellular telephones Satellites)bull Wireless sensor networks
28
Wireless Networks (2)
(a) Bluetooth configuration(b) Wireless LAN
29
Wireless Networks (3)
(a) Individual mobile computers(b) A flying LAN
30
Home Network Categories
Computers (desktop PC PDA shared peripherals) Entertainment (TV DVD VCR camera stereo MP3) Telecomm (telephone cell phone intercom fax) Appliances (microwave fridge clock furnace airco
light) Telemetry (utility meter smokeburglar alarm babycam)
31
Fundamentally different properties
1 Devices have to be easy to install
2 The network and devices have to be foolproof in
operation
3 Low price is essential
4 The network needs sufficient capacity ( for multimedia
application)
5 The network interface and wiring have to be stable for
many years
6 Security and reliability will be very important
(minimize false alarm or misalarm) Home networks may be wired or wireless
32
Internetworks
bull Internetworks connect networks with different hardware
and softwarebull A collection of interconnected networks is called
an internetwork or internetbull Internet is one specific internetbull Gateways are used to make the connection and to
provide the necessary translation (protocol convertion)
33
Network Software
bull Protocol Hierarchies (Layer structure)bull Design Issues for the Layersbull Connection-Oriented and Connectionless Servicesbull Service Primitivesbull The Relationship of Services to Protocols
34
Network Software
Protocol Hierarchiesndash a series of layers (levels)
ndash lower layer provides service to higher layers
ndash protocol bull an agreement between the communication parties on how
communication is to proceed
ndash Peers bull the corresponding layers on different machines
ndash Network architecture a set of layers and protocols
ndash Protocol stack bull a list of protocols used by a certain system one protocol per
layer
35
Network SoftwareProtocol Hierarchies
Layers protocols and interfaces
Peer
Network Architecture A set of layers and protocols Protocol Stack A list of protocols used by a certain system one protocol per layer
Virtual Communication
PhysicalCommunication
36
Layering
To make things simple modularization
Different layer has different functions
Create layer boundary such that description of services can be small number of interactions across boundary are minimized potential for interface standardized
Different level of abstraction in the handling of data (eg syntax semantics)
Provide appropriate services to upper layer
Use service primitives of lower layer
Network Software
37
Protocol Hierarchies (2)
The philosopher-translator-secretary architecture
38
Protocol Hierarchies (3)
Example information flow supporting virtual communication in layer 5
Message segmentation Encapsulation
39
Design Issues for the Layers
bull Addressing (telephone number e-mail address IP addresshellip)
bull Error Control (error correction codes ARQ HARQhellip)bull Flow Control (feedback-based rate-based)bull Multiplexing (gathering several small messages with the
same destination into a single large message or vice versa Demultiplexing)
bull Routing (directing traffic to the destination)
40
Design Issues for Layers
Identify senders and receivers ndash multiple computers and processes addressing
Data transferndash simplex half-duplex full-duplex communication
ndash of logical channels per connections priorities Error control
ndash error detection
ndash error correction Sequencing of pieces
41
Design Issues for Layers Flow control
ndash feedback from the receiver
ndash agreed upon transmission rate Length of messages
ndash long messages disassemble transmit and reassmeble messages
ndash short messages gather several small messages Multiplexing and Demultiplexing
ndash when expensive to set up a separate connection
ndash needed in physical layer Routing split over two or more layers
ndash High level London -gt France or Germany -gt Rome
ndash Low level many available circuits
42
Connection-Oriented and Connectionless Services
Six different types of service
43
Service Primitives (Operations)
Five service primitives for implementing a simple connection-oriented service
A service is formally defined by a set of primitives (operations) available to a user process to access the services
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
20
Local Area Networks (LANs)
Two broadcast networks(a) Bus(b) Ring
middot Characterics of LANs (a) privated-owned (b) small size (c) transmission technology (d) topology
middot Ethernets are most popular (up to 10 Gbs)
21
Local Area Networks Characteristics
ndash small size
ndash transmission technologybull single cable
bull 10Mbps ~ 10Gbs
bull 10Gbs 10000000000 bps
ndash topology
bull bus
ndash Ethernet (IEEE 8023) 10 or 100 Mbps (10Gbs)
bull ring
ndash IBM token ring (IEEE 8025) 4 or 16 Mbps
Channel allocation of broadcast networksndash static each machine has an allocated time slot
ndash dynamic
22
Metropolitan Area Networks
A metropolitan area network based on cable TV
23
Wide Area Networks (WANs)
Relation between hosts on LANs and the subnet
middotWANs are point-to-point networks
middotWANs consist of two distinct components transmission lines (copper fiber microwave) and switches (electronics optics)
Store-and-forward or packet-switched subnet
24
Network Topology
25
Subnet (WANs)Subnet (WANs) is consists of two components
ndash transmission lines (circuits channels trunks)bull move bits between machines
ndash switching elementsbull connect transmission lines
bull Router also called packet switching nodes intermediate systems and data switching exchanges
bull Operate in store-and-forward or packet-switched mode
26
Wide Area Networks (2)
A stream of packets from sender to receiver (virtual- circuit)
Routing decisions are made locallymiddot How A makes that decision is called the routing algorithm Will be studied in detail in Chapter 5
917 End
27
Wireless Networks
Categories of wireless networksbull System interconnection
(short-range radio eg Bluetooth)bull Wireless LANs
(80211a 80211b 80211g)bull Wireless WANs
(80216 Cellular telephones Satellites)bull Wireless sensor networks
28
Wireless Networks (2)
(a) Bluetooth configuration(b) Wireless LAN
29
Wireless Networks (3)
(a) Individual mobile computers(b) A flying LAN
30
Home Network Categories
Computers (desktop PC PDA shared peripherals) Entertainment (TV DVD VCR camera stereo MP3) Telecomm (telephone cell phone intercom fax) Appliances (microwave fridge clock furnace airco
light) Telemetry (utility meter smokeburglar alarm babycam)
31
Fundamentally different properties
1 Devices have to be easy to install
2 The network and devices have to be foolproof in
operation
3 Low price is essential
4 The network needs sufficient capacity ( for multimedia
application)
5 The network interface and wiring have to be stable for
many years
6 Security and reliability will be very important
(minimize false alarm or misalarm) Home networks may be wired or wireless
32
Internetworks
bull Internetworks connect networks with different hardware
and softwarebull A collection of interconnected networks is called
an internetwork or internetbull Internet is one specific internetbull Gateways are used to make the connection and to
provide the necessary translation (protocol convertion)
33
Network Software
bull Protocol Hierarchies (Layer structure)bull Design Issues for the Layersbull Connection-Oriented and Connectionless Servicesbull Service Primitivesbull The Relationship of Services to Protocols
34
Network Software
Protocol Hierarchiesndash a series of layers (levels)
ndash lower layer provides service to higher layers
ndash protocol bull an agreement between the communication parties on how
communication is to proceed
ndash Peers bull the corresponding layers on different machines
ndash Network architecture a set of layers and protocols
ndash Protocol stack bull a list of protocols used by a certain system one protocol per
layer
35
Network SoftwareProtocol Hierarchies
Layers protocols and interfaces
Peer
Network Architecture A set of layers and protocols Protocol Stack A list of protocols used by a certain system one protocol per layer
Virtual Communication
PhysicalCommunication
36
Layering
To make things simple modularization
Different layer has different functions
Create layer boundary such that description of services can be small number of interactions across boundary are minimized potential for interface standardized
Different level of abstraction in the handling of data (eg syntax semantics)
Provide appropriate services to upper layer
Use service primitives of lower layer
Network Software
37
Protocol Hierarchies (2)
The philosopher-translator-secretary architecture
38
Protocol Hierarchies (3)
Example information flow supporting virtual communication in layer 5
Message segmentation Encapsulation
39
Design Issues for the Layers
bull Addressing (telephone number e-mail address IP addresshellip)
bull Error Control (error correction codes ARQ HARQhellip)bull Flow Control (feedback-based rate-based)bull Multiplexing (gathering several small messages with the
same destination into a single large message or vice versa Demultiplexing)
bull Routing (directing traffic to the destination)
40
Design Issues for Layers
Identify senders and receivers ndash multiple computers and processes addressing
Data transferndash simplex half-duplex full-duplex communication
ndash of logical channels per connections priorities Error control
ndash error detection
ndash error correction Sequencing of pieces
41
Design Issues for Layers Flow control
ndash feedback from the receiver
ndash agreed upon transmission rate Length of messages
ndash long messages disassemble transmit and reassmeble messages
ndash short messages gather several small messages Multiplexing and Demultiplexing
ndash when expensive to set up a separate connection
ndash needed in physical layer Routing split over two or more layers
ndash High level London -gt France or Germany -gt Rome
ndash Low level many available circuits
42
Connection-Oriented and Connectionless Services
Six different types of service
43
Service Primitives (Operations)
Five service primitives for implementing a simple connection-oriented service
A service is formally defined by a set of primitives (operations) available to a user process to access the services
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
21
Local Area Networks Characteristics
ndash small size
ndash transmission technologybull single cable
bull 10Mbps ~ 10Gbs
bull 10Gbs 10000000000 bps
ndash topology
bull bus
ndash Ethernet (IEEE 8023) 10 or 100 Mbps (10Gbs)
bull ring
ndash IBM token ring (IEEE 8025) 4 or 16 Mbps
Channel allocation of broadcast networksndash static each machine has an allocated time slot
ndash dynamic
22
Metropolitan Area Networks
A metropolitan area network based on cable TV
23
Wide Area Networks (WANs)
Relation between hosts on LANs and the subnet
middotWANs are point-to-point networks
middotWANs consist of two distinct components transmission lines (copper fiber microwave) and switches (electronics optics)
Store-and-forward or packet-switched subnet
24
Network Topology
25
Subnet (WANs)Subnet (WANs) is consists of two components
ndash transmission lines (circuits channels trunks)bull move bits between machines
ndash switching elementsbull connect transmission lines
bull Router also called packet switching nodes intermediate systems and data switching exchanges
bull Operate in store-and-forward or packet-switched mode
26
Wide Area Networks (2)
A stream of packets from sender to receiver (virtual- circuit)
Routing decisions are made locallymiddot How A makes that decision is called the routing algorithm Will be studied in detail in Chapter 5
917 End
27
Wireless Networks
Categories of wireless networksbull System interconnection
(short-range radio eg Bluetooth)bull Wireless LANs
(80211a 80211b 80211g)bull Wireless WANs
(80216 Cellular telephones Satellites)bull Wireless sensor networks
28
Wireless Networks (2)
(a) Bluetooth configuration(b) Wireless LAN
29
Wireless Networks (3)
(a) Individual mobile computers(b) A flying LAN
30
Home Network Categories
Computers (desktop PC PDA shared peripherals) Entertainment (TV DVD VCR camera stereo MP3) Telecomm (telephone cell phone intercom fax) Appliances (microwave fridge clock furnace airco
light) Telemetry (utility meter smokeburglar alarm babycam)
31
Fundamentally different properties
1 Devices have to be easy to install
2 The network and devices have to be foolproof in
operation
3 Low price is essential
4 The network needs sufficient capacity ( for multimedia
application)
5 The network interface and wiring have to be stable for
many years
6 Security and reliability will be very important
(minimize false alarm or misalarm) Home networks may be wired or wireless
32
Internetworks
bull Internetworks connect networks with different hardware
and softwarebull A collection of interconnected networks is called
an internetwork or internetbull Internet is one specific internetbull Gateways are used to make the connection and to
provide the necessary translation (protocol convertion)
33
Network Software
bull Protocol Hierarchies (Layer structure)bull Design Issues for the Layersbull Connection-Oriented and Connectionless Servicesbull Service Primitivesbull The Relationship of Services to Protocols
34
Network Software
Protocol Hierarchiesndash a series of layers (levels)
ndash lower layer provides service to higher layers
ndash protocol bull an agreement between the communication parties on how
communication is to proceed
ndash Peers bull the corresponding layers on different machines
ndash Network architecture a set of layers and protocols
ndash Protocol stack bull a list of protocols used by a certain system one protocol per
layer
35
Network SoftwareProtocol Hierarchies
Layers protocols and interfaces
Peer
Network Architecture A set of layers and protocols Protocol Stack A list of protocols used by a certain system one protocol per layer
Virtual Communication
PhysicalCommunication
36
Layering
To make things simple modularization
Different layer has different functions
Create layer boundary such that description of services can be small number of interactions across boundary are minimized potential for interface standardized
Different level of abstraction in the handling of data (eg syntax semantics)
Provide appropriate services to upper layer
Use service primitives of lower layer
Network Software
37
Protocol Hierarchies (2)
The philosopher-translator-secretary architecture
38
Protocol Hierarchies (3)
Example information flow supporting virtual communication in layer 5
Message segmentation Encapsulation
39
Design Issues for the Layers
bull Addressing (telephone number e-mail address IP addresshellip)
bull Error Control (error correction codes ARQ HARQhellip)bull Flow Control (feedback-based rate-based)bull Multiplexing (gathering several small messages with the
same destination into a single large message or vice versa Demultiplexing)
bull Routing (directing traffic to the destination)
40
Design Issues for Layers
Identify senders and receivers ndash multiple computers and processes addressing
Data transferndash simplex half-duplex full-duplex communication
ndash of logical channels per connections priorities Error control
ndash error detection
ndash error correction Sequencing of pieces
41
Design Issues for Layers Flow control
ndash feedback from the receiver
ndash agreed upon transmission rate Length of messages
ndash long messages disassemble transmit and reassmeble messages
ndash short messages gather several small messages Multiplexing and Demultiplexing
ndash when expensive to set up a separate connection
ndash needed in physical layer Routing split over two or more layers
ndash High level London -gt France or Germany -gt Rome
ndash Low level many available circuits
42
Connection-Oriented and Connectionless Services
Six different types of service
43
Service Primitives (Operations)
Five service primitives for implementing a simple connection-oriented service
A service is formally defined by a set of primitives (operations) available to a user process to access the services
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
22
Metropolitan Area Networks
A metropolitan area network based on cable TV
23
Wide Area Networks (WANs)
Relation between hosts on LANs and the subnet
middotWANs are point-to-point networks
middotWANs consist of two distinct components transmission lines (copper fiber microwave) and switches (electronics optics)
Store-and-forward or packet-switched subnet
24
Network Topology
25
Subnet (WANs)Subnet (WANs) is consists of two components
ndash transmission lines (circuits channels trunks)bull move bits between machines
ndash switching elementsbull connect transmission lines
bull Router also called packet switching nodes intermediate systems and data switching exchanges
bull Operate in store-and-forward or packet-switched mode
26
Wide Area Networks (2)
A stream of packets from sender to receiver (virtual- circuit)
Routing decisions are made locallymiddot How A makes that decision is called the routing algorithm Will be studied in detail in Chapter 5
917 End
27
Wireless Networks
Categories of wireless networksbull System interconnection
(short-range radio eg Bluetooth)bull Wireless LANs
(80211a 80211b 80211g)bull Wireless WANs
(80216 Cellular telephones Satellites)bull Wireless sensor networks
28
Wireless Networks (2)
(a) Bluetooth configuration(b) Wireless LAN
29
Wireless Networks (3)
(a) Individual mobile computers(b) A flying LAN
30
Home Network Categories
Computers (desktop PC PDA shared peripherals) Entertainment (TV DVD VCR camera stereo MP3) Telecomm (telephone cell phone intercom fax) Appliances (microwave fridge clock furnace airco
light) Telemetry (utility meter smokeburglar alarm babycam)
31
Fundamentally different properties
1 Devices have to be easy to install
2 The network and devices have to be foolproof in
operation
3 Low price is essential
4 The network needs sufficient capacity ( for multimedia
application)
5 The network interface and wiring have to be stable for
many years
6 Security and reliability will be very important
(minimize false alarm or misalarm) Home networks may be wired or wireless
32
Internetworks
bull Internetworks connect networks with different hardware
and softwarebull A collection of interconnected networks is called
an internetwork or internetbull Internet is one specific internetbull Gateways are used to make the connection and to
provide the necessary translation (protocol convertion)
33
Network Software
bull Protocol Hierarchies (Layer structure)bull Design Issues for the Layersbull Connection-Oriented and Connectionless Servicesbull Service Primitivesbull The Relationship of Services to Protocols
34
Network Software
Protocol Hierarchiesndash a series of layers (levels)
ndash lower layer provides service to higher layers
ndash protocol bull an agreement between the communication parties on how
communication is to proceed
ndash Peers bull the corresponding layers on different machines
ndash Network architecture a set of layers and protocols
ndash Protocol stack bull a list of protocols used by a certain system one protocol per
layer
35
Network SoftwareProtocol Hierarchies
Layers protocols and interfaces
Peer
Network Architecture A set of layers and protocols Protocol Stack A list of protocols used by a certain system one protocol per layer
Virtual Communication
PhysicalCommunication
36
Layering
To make things simple modularization
Different layer has different functions
Create layer boundary such that description of services can be small number of interactions across boundary are minimized potential for interface standardized
Different level of abstraction in the handling of data (eg syntax semantics)
Provide appropriate services to upper layer
Use service primitives of lower layer
Network Software
37
Protocol Hierarchies (2)
The philosopher-translator-secretary architecture
38
Protocol Hierarchies (3)
Example information flow supporting virtual communication in layer 5
Message segmentation Encapsulation
39
Design Issues for the Layers
bull Addressing (telephone number e-mail address IP addresshellip)
bull Error Control (error correction codes ARQ HARQhellip)bull Flow Control (feedback-based rate-based)bull Multiplexing (gathering several small messages with the
same destination into a single large message or vice versa Demultiplexing)
bull Routing (directing traffic to the destination)
40
Design Issues for Layers
Identify senders and receivers ndash multiple computers and processes addressing
Data transferndash simplex half-duplex full-duplex communication
ndash of logical channels per connections priorities Error control
ndash error detection
ndash error correction Sequencing of pieces
41
Design Issues for Layers Flow control
ndash feedback from the receiver
ndash agreed upon transmission rate Length of messages
ndash long messages disassemble transmit and reassmeble messages
ndash short messages gather several small messages Multiplexing and Demultiplexing
ndash when expensive to set up a separate connection
ndash needed in physical layer Routing split over two or more layers
ndash High level London -gt France or Germany -gt Rome
ndash Low level many available circuits
42
Connection-Oriented and Connectionless Services
Six different types of service
43
Service Primitives (Operations)
Five service primitives for implementing a simple connection-oriented service
A service is formally defined by a set of primitives (operations) available to a user process to access the services
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
23
Wide Area Networks (WANs)
Relation between hosts on LANs and the subnet
middotWANs are point-to-point networks
middotWANs consist of two distinct components transmission lines (copper fiber microwave) and switches (electronics optics)
Store-and-forward or packet-switched subnet
24
Network Topology
25
Subnet (WANs)Subnet (WANs) is consists of two components
ndash transmission lines (circuits channels trunks)bull move bits between machines
ndash switching elementsbull connect transmission lines
bull Router also called packet switching nodes intermediate systems and data switching exchanges
bull Operate in store-and-forward or packet-switched mode
26
Wide Area Networks (2)
A stream of packets from sender to receiver (virtual- circuit)
Routing decisions are made locallymiddot How A makes that decision is called the routing algorithm Will be studied in detail in Chapter 5
917 End
27
Wireless Networks
Categories of wireless networksbull System interconnection
(short-range radio eg Bluetooth)bull Wireless LANs
(80211a 80211b 80211g)bull Wireless WANs
(80216 Cellular telephones Satellites)bull Wireless sensor networks
28
Wireless Networks (2)
(a) Bluetooth configuration(b) Wireless LAN
29
Wireless Networks (3)
(a) Individual mobile computers(b) A flying LAN
30
Home Network Categories
Computers (desktop PC PDA shared peripherals) Entertainment (TV DVD VCR camera stereo MP3) Telecomm (telephone cell phone intercom fax) Appliances (microwave fridge clock furnace airco
light) Telemetry (utility meter smokeburglar alarm babycam)
31
Fundamentally different properties
1 Devices have to be easy to install
2 The network and devices have to be foolproof in
operation
3 Low price is essential
4 The network needs sufficient capacity ( for multimedia
application)
5 The network interface and wiring have to be stable for
many years
6 Security and reliability will be very important
(minimize false alarm or misalarm) Home networks may be wired or wireless
32
Internetworks
bull Internetworks connect networks with different hardware
and softwarebull A collection of interconnected networks is called
an internetwork or internetbull Internet is one specific internetbull Gateways are used to make the connection and to
provide the necessary translation (protocol convertion)
33
Network Software
bull Protocol Hierarchies (Layer structure)bull Design Issues for the Layersbull Connection-Oriented and Connectionless Servicesbull Service Primitivesbull The Relationship of Services to Protocols
34
Network Software
Protocol Hierarchiesndash a series of layers (levels)
ndash lower layer provides service to higher layers
ndash protocol bull an agreement between the communication parties on how
communication is to proceed
ndash Peers bull the corresponding layers on different machines
ndash Network architecture a set of layers and protocols
ndash Protocol stack bull a list of protocols used by a certain system one protocol per
layer
35
Network SoftwareProtocol Hierarchies
Layers protocols and interfaces
Peer
Network Architecture A set of layers and protocols Protocol Stack A list of protocols used by a certain system one protocol per layer
Virtual Communication
PhysicalCommunication
36
Layering
To make things simple modularization
Different layer has different functions
Create layer boundary such that description of services can be small number of interactions across boundary are minimized potential for interface standardized
Different level of abstraction in the handling of data (eg syntax semantics)
Provide appropriate services to upper layer
Use service primitives of lower layer
Network Software
37
Protocol Hierarchies (2)
The philosopher-translator-secretary architecture
38
Protocol Hierarchies (3)
Example information flow supporting virtual communication in layer 5
Message segmentation Encapsulation
39
Design Issues for the Layers
bull Addressing (telephone number e-mail address IP addresshellip)
bull Error Control (error correction codes ARQ HARQhellip)bull Flow Control (feedback-based rate-based)bull Multiplexing (gathering several small messages with the
same destination into a single large message or vice versa Demultiplexing)
bull Routing (directing traffic to the destination)
40
Design Issues for Layers
Identify senders and receivers ndash multiple computers and processes addressing
Data transferndash simplex half-duplex full-duplex communication
ndash of logical channels per connections priorities Error control
ndash error detection
ndash error correction Sequencing of pieces
41
Design Issues for Layers Flow control
ndash feedback from the receiver
ndash agreed upon transmission rate Length of messages
ndash long messages disassemble transmit and reassmeble messages
ndash short messages gather several small messages Multiplexing and Demultiplexing
ndash when expensive to set up a separate connection
ndash needed in physical layer Routing split over two or more layers
ndash High level London -gt France or Germany -gt Rome
ndash Low level many available circuits
42
Connection-Oriented and Connectionless Services
Six different types of service
43
Service Primitives (Operations)
Five service primitives for implementing a simple connection-oriented service
A service is formally defined by a set of primitives (operations) available to a user process to access the services
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
24
Network Topology
25
Subnet (WANs)Subnet (WANs) is consists of two components
ndash transmission lines (circuits channels trunks)bull move bits between machines
ndash switching elementsbull connect transmission lines
bull Router also called packet switching nodes intermediate systems and data switching exchanges
bull Operate in store-and-forward or packet-switched mode
26
Wide Area Networks (2)
A stream of packets from sender to receiver (virtual- circuit)
Routing decisions are made locallymiddot How A makes that decision is called the routing algorithm Will be studied in detail in Chapter 5
917 End
27
Wireless Networks
Categories of wireless networksbull System interconnection
(short-range radio eg Bluetooth)bull Wireless LANs
(80211a 80211b 80211g)bull Wireless WANs
(80216 Cellular telephones Satellites)bull Wireless sensor networks
28
Wireless Networks (2)
(a) Bluetooth configuration(b) Wireless LAN
29
Wireless Networks (3)
(a) Individual mobile computers(b) A flying LAN
30
Home Network Categories
Computers (desktop PC PDA shared peripherals) Entertainment (TV DVD VCR camera stereo MP3) Telecomm (telephone cell phone intercom fax) Appliances (microwave fridge clock furnace airco
light) Telemetry (utility meter smokeburglar alarm babycam)
31
Fundamentally different properties
1 Devices have to be easy to install
2 The network and devices have to be foolproof in
operation
3 Low price is essential
4 The network needs sufficient capacity ( for multimedia
application)
5 The network interface and wiring have to be stable for
many years
6 Security and reliability will be very important
(minimize false alarm or misalarm) Home networks may be wired or wireless
32
Internetworks
bull Internetworks connect networks with different hardware
and softwarebull A collection of interconnected networks is called
an internetwork or internetbull Internet is one specific internetbull Gateways are used to make the connection and to
provide the necessary translation (protocol convertion)
33
Network Software
bull Protocol Hierarchies (Layer structure)bull Design Issues for the Layersbull Connection-Oriented and Connectionless Servicesbull Service Primitivesbull The Relationship of Services to Protocols
34
Network Software
Protocol Hierarchiesndash a series of layers (levels)
ndash lower layer provides service to higher layers
ndash protocol bull an agreement between the communication parties on how
communication is to proceed
ndash Peers bull the corresponding layers on different machines
ndash Network architecture a set of layers and protocols
ndash Protocol stack bull a list of protocols used by a certain system one protocol per
layer
35
Network SoftwareProtocol Hierarchies
Layers protocols and interfaces
Peer
Network Architecture A set of layers and protocols Protocol Stack A list of protocols used by a certain system one protocol per layer
Virtual Communication
PhysicalCommunication
36
Layering
To make things simple modularization
Different layer has different functions
Create layer boundary such that description of services can be small number of interactions across boundary are minimized potential for interface standardized
Different level of abstraction in the handling of data (eg syntax semantics)
Provide appropriate services to upper layer
Use service primitives of lower layer
Network Software
37
Protocol Hierarchies (2)
The philosopher-translator-secretary architecture
38
Protocol Hierarchies (3)
Example information flow supporting virtual communication in layer 5
Message segmentation Encapsulation
39
Design Issues for the Layers
bull Addressing (telephone number e-mail address IP addresshellip)
bull Error Control (error correction codes ARQ HARQhellip)bull Flow Control (feedback-based rate-based)bull Multiplexing (gathering several small messages with the
same destination into a single large message or vice versa Demultiplexing)
bull Routing (directing traffic to the destination)
40
Design Issues for Layers
Identify senders and receivers ndash multiple computers and processes addressing
Data transferndash simplex half-duplex full-duplex communication
ndash of logical channels per connections priorities Error control
ndash error detection
ndash error correction Sequencing of pieces
41
Design Issues for Layers Flow control
ndash feedback from the receiver
ndash agreed upon transmission rate Length of messages
ndash long messages disassemble transmit and reassmeble messages
ndash short messages gather several small messages Multiplexing and Demultiplexing
ndash when expensive to set up a separate connection
ndash needed in physical layer Routing split over two or more layers
ndash High level London -gt France or Germany -gt Rome
ndash Low level many available circuits
42
Connection-Oriented and Connectionless Services
Six different types of service
43
Service Primitives (Operations)
Five service primitives for implementing a simple connection-oriented service
A service is formally defined by a set of primitives (operations) available to a user process to access the services
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
25
Subnet (WANs)Subnet (WANs) is consists of two components
ndash transmission lines (circuits channels trunks)bull move bits between machines
ndash switching elementsbull connect transmission lines
bull Router also called packet switching nodes intermediate systems and data switching exchanges
bull Operate in store-and-forward or packet-switched mode
26
Wide Area Networks (2)
A stream of packets from sender to receiver (virtual- circuit)
Routing decisions are made locallymiddot How A makes that decision is called the routing algorithm Will be studied in detail in Chapter 5
917 End
27
Wireless Networks
Categories of wireless networksbull System interconnection
(short-range radio eg Bluetooth)bull Wireless LANs
(80211a 80211b 80211g)bull Wireless WANs
(80216 Cellular telephones Satellites)bull Wireless sensor networks
28
Wireless Networks (2)
(a) Bluetooth configuration(b) Wireless LAN
29
Wireless Networks (3)
(a) Individual mobile computers(b) A flying LAN
30
Home Network Categories
Computers (desktop PC PDA shared peripherals) Entertainment (TV DVD VCR camera stereo MP3) Telecomm (telephone cell phone intercom fax) Appliances (microwave fridge clock furnace airco
light) Telemetry (utility meter smokeburglar alarm babycam)
31
Fundamentally different properties
1 Devices have to be easy to install
2 The network and devices have to be foolproof in
operation
3 Low price is essential
4 The network needs sufficient capacity ( for multimedia
application)
5 The network interface and wiring have to be stable for
many years
6 Security and reliability will be very important
(minimize false alarm or misalarm) Home networks may be wired or wireless
32
Internetworks
bull Internetworks connect networks with different hardware
and softwarebull A collection of interconnected networks is called
an internetwork or internetbull Internet is one specific internetbull Gateways are used to make the connection and to
provide the necessary translation (protocol convertion)
33
Network Software
bull Protocol Hierarchies (Layer structure)bull Design Issues for the Layersbull Connection-Oriented and Connectionless Servicesbull Service Primitivesbull The Relationship of Services to Protocols
34
Network Software
Protocol Hierarchiesndash a series of layers (levels)
ndash lower layer provides service to higher layers
ndash protocol bull an agreement between the communication parties on how
communication is to proceed
ndash Peers bull the corresponding layers on different machines
ndash Network architecture a set of layers and protocols
ndash Protocol stack bull a list of protocols used by a certain system one protocol per
layer
35
Network SoftwareProtocol Hierarchies
Layers protocols and interfaces
Peer
Network Architecture A set of layers and protocols Protocol Stack A list of protocols used by a certain system one protocol per layer
Virtual Communication
PhysicalCommunication
36
Layering
To make things simple modularization
Different layer has different functions
Create layer boundary such that description of services can be small number of interactions across boundary are minimized potential for interface standardized
Different level of abstraction in the handling of data (eg syntax semantics)
Provide appropriate services to upper layer
Use service primitives of lower layer
Network Software
37
Protocol Hierarchies (2)
The philosopher-translator-secretary architecture
38
Protocol Hierarchies (3)
Example information flow supporting virtual communication in layer 5
Message segmentation Encapsulation
39
Design Issues for the Layers
bull Addressing (telephone number e-mail address IP addresshellip)
bull Error Control (error correction codes ARQ HARQhellip)bull Flow Control (feedback-based rate-based)bull Multiplexing (gathering several small messages with the
same destination into a single large message or vice versa Demultiplexing)
bull Routing (directing traffic to the destination)
40
Design Issues for Layers
Identify senders and receivers ndash multiple computers and processes addressing
Data transferndash simplex half-duplex full-duplex communication
ndash of logical channels per connections priorities Error control
ndash error detection
ndash error correction Sequencing of pieces
41
Design Issues for Layers Flow control
ndash feedback from the receiver
ndash agreed upon transmission rate Length of messages
ndash long messages disassemble transmit and reassmeble messages
ndash short messages gather several small messages Multiplexing and Demultiplexing
ndash when expensive to set up a separate connection
ndash needed in physical layer Routing split over two or more layers
ndash High level London -gt France or Germany -gt Rome
ndash Low level many available circuits
42
Connection-Oriented and Connectionless Services
Six different types of service
43
Service Primitives (Operations)
Five service primitives for implementing a simple connection-oriented service
A service is formally defined by a set of primitives (operations) available to a user process to access the services
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
26
Wide Area Networks (2)
A stream of packets from sender to receiver (virtual- circuit)
Routing decisions are made locallymiddot How A makes that decision is called the routing algorithm Will be studied in detail in Chapter 5
917 End
27
Wireless Networks
Categories of wireless networksbull System interconnection
(short-range radio eg Bluetooth)bull Wireless LANs
(80211a 80211b 80211g)bull Wireless WANs
(80216 Cellular telephones Satellites)bull Wireless sensor networks
28
Wireless Networks (2)
(a) Bluetooth configuration(b) Wireless LAN
29
Wireless Networks (3)
(a) Individual mobile computers(b) A flying LAN
30
Home Network Categories
Computers (desktop PC PDA shared peripherals) Entertainment (TV DVD VCR camera stereo MP3) Telecomm (telephone cell phone intercom fax) Appliances (microwave fridge clock furnace airco
light) Telemetry (utility meter smokeburglar alarm babycam)
31
Fundamentally different properties
1 Devices have to be easy to install
2 The network and devices have to be foolproof in
operation
3 Low price is essential
4 The network needs sufficient capacity ( for multimedia
application)
5 The network interface and wiring have to be stable for
many years
6 Security and reliability will be very important
(minimize false alarm or misalarm) Home networks may be wired or wireless
32
Internetworks
bull Internetworks connect networks with different hardware
and softwarebull A collection of interconnected networks is called
an internetwork or internetbull Internet is one specific internetbull Gateways are used to make the connection and to
provide the necessary translation (protocol convertion)
33
Network Software
bull Protocol Hierarchies (Layer structure)bull Design Issues for the Layersbull Connection-Oriented and Connectionless Servicesbull Service Primitivesbull The Relationship of Services to Protocols
34
Network Software
Protocol Hierarchiesndash a series of layers (levels)
ndash lower layer provides service to higher layers
ndash protocol bull an agreement between the communication parties on how
communication is to proceed
ndash Peers bull the corresponding layers on different machines
ndash Network architecture a set of layers and protocols
ndash Protocol stack bull a list of protocols used by a certain system one protocol per
layer
35
Network SoftwareProtocol Hierarchies
Layers protocols and interfaces
Peer
Network Architecture A set of layers and protocols Protocol Stack A list of protocols used by a certain system one protocol per layer
Virtual Communication
PhysicalCommunication
36
Layering
To make things simple modularization
Different layer has different functions
Create layer boundary such that description of services can be small number of interactions across boundary are minimized potential for interface standardized
Different level of abstraction in the handling of data (eg syntax semantics)
Provide appropriate services to upper layer
Use service primitives of lower layer
Network Software
37
Protocol Hierarchies (2)
The philosopher-translator-secretary architecture
38
Protocol Hierarchies (3)
Example information flow supporting virtual communication in layer 5
Message segmentation Encapsulation
39
Design Issues for the Layers
bull Addressing (telephone number e-mail address IP addresshellip)
bull Error Control (error correction codes ARQ HARQhellip)bull Flow Control (feedback-based rate-based)bull Multiplexing (gathering several small messages with the
same destination into a single large message or vice versa Demultiplexing)
bull Routing (directing traffic to the destination)
40
Design Issues for Layers
Identify senders and receivers ndash multiple computers and processes addressing
Data transferndash simplex half-duplex full-duplex communication
ndash of logical channels per connections priorities Error control
ndash error detection
ndash error correction Sequencing of pieces
41
Design Issues for Layers Flow control
ndash feedback from the receiver
ndash agreed upon transmission rate Length of messages
ndash long messages disassemble transmit and reassmeble messages
ndash short messages gather several small messages Multiplexing and Demultiplexing
ndash when expensive to set up a separate connection
ndash needed in physical layer Routing split over two or more layers
ndash High level London -gt France or Germany -gt Rome
ndash Low level many available circuits
42
Connection-Oriented and Connectionless Services
Six different types of service
43
Service Primitives (Operations)
Five service primitives for implementing a simple connection-oriented service
A service is formally defined by a set of primitives (operations) available to a user process to access the services
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
27
Wireless Networks
Categories of wireless networksbull System interconnection
(short-range radio eg Bluetooth)bull Wireless LANs
(80211a 80211b 80211g)bull Wireless WANs
(80216 Cellular telephones Satellites)bull Wireless sensor networks
28
Wireless Networks (2)
(a) Bluetooth configuration(b) Wireless LAN
29
Wireless Networks (3)
(a) Individual mobile computers(b) A flying LAN
30
Home Network Categories
Computers (desktop PC PDA shared peripherals) Entertainment (TV DVD VCR camera stereo MP3) Telecomm (telephone cell phone intercom fax) Appliances (microwave fridge clock furnace airco
light) Telemetry (utility meter smokeburglar alarm babycam)
31
Fundamentally different properties
1 Devices have to be easy to install
2 The network and devices have to be foolproof in
operation
3 Low price is essential
4 The network needs sufficient capacity ( for multimedia
application)
5 The network interface and wiring have to be stable for
many years
6 Security and reliability will be very important
(minimize false alarm or misalarm) Home networks may be wired or wireless
32
Internetworks
bull Internetworks connect networks with different hardware
and softwarebull A collection of interconnected networks is called
an internetwork or internetbull Internet is one specific internetbull Gateways are used to make the connection and to
provide the necessary translation (protocol convertion)
33
Network Software
bull Protocol Hierarchies (Layer structure)bull Design Issues for the Layersbull Connection-Oriented and Connectionless Servicesbull Service Primitivesbull The Relationship of Services to Protocols
34
Network Software
Protocol Hierarchiesndash a series of layers (levels)
ndash lower layer provides service to higher layers
ndash protocol bull an agreement between the communication parties on how
communication is to proceed
ndash Peers bull the corresponding layers on different machines
ndash Network architecture a set of layers and protocols
ndash Protocol stack bull a list of protocols used by a certain system one protocol per
layer
35
Network SoftwareProtocol Hierarchies
Layers protocols and interfaces
Peer
Network Architecture A set of layers and protocols Protocol Stack A list of protocols used by a certain system one protocol per layer
Virtual Communication
PhysicalCommunication
36
Layering
To make things simple modularization
Different layer has different functions
Create layer boundary such that description of services can be small number of interactions across boundary are minimized potential for interface standardized
Different level of abstraction in the handling of data (eg syntax semantics)
Provide appropriate services to upper layer
Use service primitives of lower layer
Network Software
37
Protocol Hierarchies (2)
The philosopher-translator-secretary architecture
38
Protocol Hierarchies (3)
Example information flow supporting virtual communication in layer 5
Message segmentation Encapsulation
39
Design Issues for the Layers
bull Addressing (telephone number e-mail address IP addresshellip)
bull Error Control (error correction codes ARQ HARQhellip)bull Flow Control (feedback-based rate-based)bull Multiplexing (gathering several small messages with the
same destination into a single large message or vice versa Demultiplexing)
bull Routing (directing traffic to the destination)
40
Design Issues for Layers
Identify senders and receivers ndash multiple computers and processes addressing
Data transferndash simplex half-duplex full-duplex communication
ndash of logical channels per connections priorities Error control
ndash error detection
ndash error correction Sequencing of pieces
41
Design Issues for Layers Flow control
ndash feedback from the receiver
ndash agreed upon transmission rate Length of messages
ndash long messages disassemble transmit and reassmeble messages
ndash short messages gather several small messages Multiplexing and Demultiplexing
ndash when expensive to set up a separate connection
ndash needed in physical layer Routing split over two or more layers
ndash High level London -gt France or Germany -gt Rome
ndash Low level many available circuits
42
Connection-Oriented and Connectionless Services
Six different types of service
43
Service Primitives (Operations)
Five service primitives for implementing a simple connection-oriented service
A service is formally defined by a set of primitives (operations) available to a user process to access the services
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
28
Wireless Networks (2)
(a) Bluetooth configuration(b) Wireless LAN
29
Wireless Networks (3)
(a) Individual mobile computers(b) A flying LAN
30
Home Network Categories
Computers (desktop PC PDA shared peripherals) Entertainment (TV DVD VCR camera stereo MP3) Telecomm (telephone cell phone intercom fax) Appliances (microwave fridge clock furnace airco
light) Telemetry (utility meter smokeburglar alarm babycam)
31
Fundamentally different properties
1 Devices have to be easy to install
2 The network and devices have to be foolproof in
operation
3 Low price is essential
4 The network needs sufficient capacity ( for multimedia
application)
5 The network interface and wiring have to be stable for
many years
6 Security and reliability will be very important
(minimize false alarm or misalarm) Home networks may be wired or wireless
32
Internetworks
bull Internetworks connect networks with different hardware
and softwarebull A collection of interconnected networks is called
an internetwork or internetbull Internet is one specific internetbull Gateways are used to make the connection and to
provide the necessary translation (protocol convertion)
33
Network Software
bull Protocol Hierarchies (Layer structure)bull Design Issues for the Layersbull Connection-Oriented and Connectionless Servicesbull Service Primitivesbull The Relationship of Services to Protocols
34
Network Software
Protocol Hierarchiesndash a series of layers (levels)
ndash lower layer provides service to higher layers
ndash protocol bull an agreement between the communication parties on how
communication is to proceed
ndash Peers bull the corresponding layers on different machines
ndash Network architecture a set of layers and protocols
ndash Protocol stack bull a list of protocols used by a certain system one protocol per
layer
35
Network SoftwareProtocol Hierarchies
Layers protocols and interfaces
Peer
Network Architecture A set of layers and protocols Protocol Stack A list of protocols used by a certain system one protocol per layer
Virtual Communication
PhysicalCommunication
36
Layering
To make things simple modularization
Different layer has different functions
Create layer boundary such that description of services can be small number of interactions across boundary are minimized potential for interface standardized
Different level of abstraction in the handling of data (eg syntax semantics)
Provide appropriate services to upper layer
Use service primitives of lower layer
Network Software
37
Protocol Hierarchies (2)
The philosopher-translator-secretary architecture
38
Protocol Hierarchies (3)
Example information flow supporting virtual communication in layer 5
Message segmentation Encapsulation
39
Design Issues for the Layers
bull Addressing (telephone number e-mail address IP addresshellip)
bull Error Control (error correction codes ARQ HARQhellip)bull Flow Control (feedback-based rate-based)bull Multiplexing (gathering several small messages with the
same destination into a single large message or vice versa Demultiplexing)
bull Routing (directing traffic to the destination)
40
Design Issues for Layers
Identify senders and receivers ndash multiple computers and processes addressing
Data transferndash simplex half-duplex full-duplex communication
ndash of logical channels per connections priorities Error control
ndash error detection
ndash error correction Sequencing of pieces
41
Design Issues for Layers Flow control
ndash feedback from the receiver
ndash agreed upon transmission rate Length of messages
ndash long messages disassemble transmit and reassmeble messages
ndash short messages gather several small messages Multiplexing and Demultiplexing
ndash when expensive to set up a separate connection
ndash needed in physical layer Routing split over two or more layers
ndash High level London -gt France or Germany -gt Rome
ndash Low level many available circuits
42
Connection-Oriented and Connectionless Services
Six different types of service
43
Service Primitives (Operations)
Five service primitives for implementing a simple connection-oriented service
A service is formally defined by a set of primitives (operations) available to a user process to access the services
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
29
Wireless Networks (3)
(a) Individual mobile computers(b) A flying LAN
30
Home Network Categories
Computers (desktop PC PDA shared peripherals) Entertainment (TV DVD VCR camera stereo MP3) Telecomm (telephone cell phone intercom fax) Appliances (microwave fridge clock furnace airco
light) Telemetry (utility meter smokeburglar alarm babycam)
31
Fundamentally different properties
1 Devices have to be easy to install
2 The network and devices have to be foolproof in
operation
3 Low price is essential
4 The network needs sufficient capacity ( for multimedia
application)
5 The network interface and wiring have to be stable for
many years
6 Security and reliability will be very important
(minimize false alarm or misalarm) Home networks may be wired or wireless
32
Internetworks
bull Internetworks connect networks with different hardware
and softwarebull A collection of interconnected networks is called
an internetwork or internetbull Internet is one specific internetbull Gateways are used to make the connection and to
provide the necessary translation (protocol convertion)
33
Network Software
bull Protocol Hierarchies (Layer structure)bull Design Issues for the Layersbull Connection-Oriented and Connectionless Servicesbull Service Primitivesbull The Relationship of Services to Protocols
34
Network Software
Protocol Hierarchiesndash a series of layers (levels)
ndash lower layer provides service to higher layers
ndash protocol bull an agreement between the communication parties on how
communication is to proceed
ndash Peers bull the corresponding layers on different machines
ndash Network architecture a set of layers and protocols
ndash Protocol stack bull a list of protocols used by a certain system one protocol per
layer
35
Network SoftwareProtocol Hierarchies
Layers protocols and interfaces
Peer
Network Architecture A set of layers and protocols Protocol Stack A list of protocols used by a certain system one protocol per layer
Virtual Communication
PhysicalCommunication
36
Layering
To make things simple modularization
Different layer has different functions
Create layer boundary such that description of services can be small number of interactions across boundary are minimized potential for interface standardized
Different level of abstraction in the handling of data (eg syntax semantics)
Provide appropriate services to upper layer
Use service primitives of lower layer
Network Software
37
Protocol Hierarchies (2)
The philosopher-translator-secretary architecture
38
Protocol Hierarchies (3)
Example information flow supporting virtual communication in layer 5
Message segmentation Encapsulation
39
Design Issues for the Layers
bull Addressing (telephone number e-mail address IP addresshellip)
bull Error Control (error correction codes ARQ HARQhellip)bull Flow Control (feedback-based rate-based)bull Multiplexing (gathering several small messages with the
same destination into a single large message or vice versa Demultiplexing)
bull Routing (directing traffic to the destination)
40
Design Issues for Layers
Identify senders and receivers ndash multiple computers and processes addressing
Data transferndash simplex half-duplex full-duplex communication
ndash of logical channels per connections priorities Error control
ndash error detection
ndash error correction Sequencing of pieces
41
Design Issues for Layers Flow control
ndash feedback from the receiver
ndash agreed upon transmission rate Length of messages
ndash long messages disassemble transmit and reassmeble messages
ndash short messages gather several small messages Multiplexing and Demultiplexing
ndash when expensive to set up a separate connection
ndash needed in physical layer Routing split over two or more layers
ndash High level London -gt France or Germany -gt Rome
ndash Low level many available circuits
42
Connection-Oriented and Connectionless Services
Six different types of service
43
Service Primitives (Operations)
Five service primitives for implementing a simple connection-oriented service
A service is formally defined by a set of primitives (operations) available to a user process to access the services
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
30
Home Network Categories
Computers (desktop PC PDA shared peripherals) Entertainment (TV DVD VCR camera stereo MP3) Telecomm (telephone cell phone intercom fax) Appliances (microwave fridge clock furnace airco
light) Telemetry (utility meter smokeburglar alarm babycam)
31
Fundamentally different properties
1 Devices have to be easy to install
2 The network and devices have to be foolproof in
operation
3 Low price is essential
4 The network needs sufficient capacity ( for multimedia
application)
5 The network interface and wiring have to be stable for
many years
6 Security and reliability will be very important
(minimize false alarm or misalarm) Home networks may be wired or wireless
32
Internetworks
bull Internetworks connect networks with different hardware
and softwarebull A collection of interconnected networks is called
an internetwork or internetbull Internet is one specific internetbull Gateways are used to make the connection and to
provide the necessary translation (protocol convertion)
33
Network Software
bull Protocol Hierarchies (Layer structure)bull Design Issues for the Layersbull Connection-Oriented and Connectionless Servicesbull Service Primitivesbull The Relationship of Services to Protocols
34
Network Software
Protocol Hierarchiesndash a series of layers (levels)
ndash lower layer provides service to higher layers
ndash protocol bull an agreement between the communication parties on how
communication is to proceed
ndash Peers bull the corresponding layers on different machines
ndash Network architecture a set of layers and protocols
ndash Protocol stack bull a list of protocols used by a certain system one protocol per
layer
35
Network SoftwareProtocol Hierarchies
Layers protocols and interfaces
Peer
Network Architecture A set of layers and protocols Protocol Stack A list of protocols used by a certain system one protocol per layer
Virtual Communication
PhysicalCommunication
36
Layering
To make things simple modularization
Different layer has different functions
Create layer boundary such that description of services can be small number of interactions across boundary are minimized potential for interface standardized
Different level of abstraction in the handling of data (eg syntax semantics)
Provide appropriate services to upper layer
Use service primitives of lower layer
Network Software
37
Protocol Hierarchies (2)
The philosopher-translator-secretary architecture
38
Protocol Hierarchies (3)
Example information flow supporting virtual communication in layer 5
Message segmentation Encapsulation
39
Design Issues for the Layers
bull Addressing (telephone number e-mail address IP addresshellip)
bull Error Control (error correction codes ARQ HARQhellip)bull Flow Control (feedback-based rate-based)bull Multiplexing (gathering several small messages with the
same destination into a single large message or vice versa Demultiplexing)
bull Routing (directing traffic to the destination)
40
Design Issues for Layers
Identify senders and receivers ndash multiple computers and processes addressing
Data transferndash simplex half-duplex full-duplex communication
ndash of logical channels per connections priorities Error control
ndash error detection
ndash error correction Sequencing of pieces
41
Design Issues for Layers Flow control
ndash feedback from the receiver
ndash agreed upon transmission rate Length of messages
ndash long messages disassemble transmit and reassmeble messages
ndash short messages gather several small messages Multiplexing and Demultiplexing
ndash when expensive to set up a separate connection
ndash needed in physical layer Routing split over two or more layers
ndash High level London -gt France or Germany -gt Rome
ndash Low level many available circuits
42
Connection-Oriented and Connectionless Services
Six different types of service
43
Service Primitives (Operations)
Five service primitives for implementing a simple connection-oriented service
A service is formally defined by a set of primitives (operations) available to a user process to access the services
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
31
Fundamentally different properties
1 Devices have to be easy to install
2 The network and devices have to be foolproof in
operation
3 Low price is essential
4 The network needs sufficient capacity ( for multimedia
application)
5 The network interface and wiring have to be stable for
many years
6 Security and reliability will be very important
(minimize false alarm or misalarm) Home networks may be wired or wireless
32
Internetworks
bull Internetworks connect networks with different hardware
and softwarebull A collection of interconnected networks is called
an internetwork or internetbull Internet is one specific internetbull Gateways are used to make the connection and to
provide the necessary translation (protocol convertion)
33
Network Software
bull Protocol Hierarchies (Layer structure)bull Design Issues for the Layersbull Connection-Oriented and Connectionless Servicesbull Service Primitivesbull The Relationship of Services to Protocols
34
Network Software
Protocol Hierarchiesndash a series of layers (levels)
ndash lower layer provides service to higher layers
ndash protocol bull an agreement between the communication parties on how
communication is to proceed
ndash Peers bull the corresponding layers on different machines
ndash Network architecture a set of layers and protocols
ndash Protocol stack bull a list of protocols used by a certain system one protocol per
layer
35
Network SoftwareProtocol Hierarchies
Layers protocols and interfaces
Peer
Network Architecture A set of layers and protocols Protocol Stack A list of protocols used by a certain system one protocol per layer
Virtual Communication
PhysicalCommunication
36
Layering
To make things simple modularization
Different layer has different functions
Create layer boundary such that description of services can be small number of interactions across boundary are minimized potential for interface standardized
Different level of abstraction in the handling of data (eg syntax semantics)
Provide appropriate services to upper layer
Use service primitives of lower layer
Network Software
37
Protocol Hierarchies (2)
The philosopher-translator-secretary architecture
38
Protocol Hierarchies (3)
Example information flow supporting virtual communication in layer 5
Message segmentation Encapsulation
39
Design Issues for the Layers
bull Addressing (telephone number e-mail address IP addresshellip)
bull Error Control (error correction codes ARQ HARQhellip)bull Flow Control (feedback-based rate-based)bull Multiplexing (gathering several small messages with the
same destination into a single large message or vice versa Demultiplexing)
bull Routing (directing traffic to the destination)
40
Design Issues for Layers
Identify senders and receivers ndash multiple computers and processes addressing
Data transferndash simplex half-duplex full-duplex communication
ndash of logical channels per connections priorities Error control
ndash error detection
ndash error correction Sequencing of pieces
41
Design Issues for Layers Flow control
ndash feedback from the receiver
ndash agreed upon transmission rate Length of messages
ndash long messages disassemble transmit and reassmeble messages
ndash short messages gather several small messages Multiplexing and Demultiplexing
ndash when expensive to set up a separate connection
ndash needed in physical layer Routing split over two or more layers
ndash High level London -gt France or Germany -gt Rome
ndash Low level many available circuits
42
Connection-Oriented and Connectionless Services
Six different types of service
43
Service Primitives (Operations)
Five service primitives for implementing a simple connection-oriented service
A service is formally defined by a set of primitives (operations) available to a user process to access the services
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
32
Internetworks
bull Internetworks connect networks with different hardware
and softwarebull A collection of interconnected networks is called
an internetwork or internetbull Internet is one specific internetbull Gateways are used to make the connection and to
provide the necessary translation (protocol convertion)
33
Network Software
bull Protocol Hierarchies (Layer structure)bull Design Issues for the Layersbull Connection-Oriented and Connectionless Servicesbull Service Primitivesbull The Relationship of Services to Protocols
34
Network Software
Protocol Hierarchiesndash a series of layers (levels)
ndash lower layer provides service to higher layers
ndash protocol bull an agreement between the communication parties on how
communication is to proceed
ndash Peers bull the corresponding layers on different machines
ndash Network architecture a set of layers and protocols
ndash Protocol stack bull a list of protocols used by a certain system one protocol per
layer
35
Network SoftwareProtocol Hierarchies
Layers protocols and interfaces
Peer
Network Architecture A set of layers and protocols Protocol Stack A list of protocols used by a certain system one protocol per layer
Virtual Communication
PhysicalCommunication
36
Layering
To make things simple modularization
Different layer has different functions
Create layer boundary such that description of services can be small number of interactions across boundary are minimized potential for interface standardized
Different level of abstraction in the handling of data (eg syntax semantics)
Provide appropriate services to upper layer
Use service primitives of lower layer
Network Software
37
Protocol Hierarchies (2)
The philosopher-translator-secretary architecture
38
Protocol Hierarchies (3)
Example information flow supporting virtual communication in layer 5
Message segmentation Encapsulation
39
Design Issues for the Layers
bull Addressing (telephone number e-mail address IP addresshellip)
bull Error Control (error correction codes ARQ HARQhellip)bull Flow Control (feedback-based rate-based)bull Multiplexing (gathering several small messages with the
same destination into a single large message or vice versa Demultiplexing)
bull Routing (directing traffic to the destination)
40
Design Issues for Layers
Identify senders and receivers ndash multiple computers and processes addressing
Data transferndash simplex half-duplex full-duplex communication
ndash of logical channels per connections priorities Error control
ndash error detection
ndash error correction Sequencing of pieces
41
Design Issues for Layers Flow control
ndash feedback from the receiver
ndash agreed upon transmission rate Length of messages
ndash long messages disassemble transmit and reassmeble messages
ndash short messages gather several small messages Multiplexing and Demultiplexing
ndash when expensive to set up a separate connection
ndash needed in physical layer Routing split over two or more layers
ndash High level London -gt France or Germany -gt Rome
ndash Low level many available circuits
42
Connection-Oriented and Connectionless Services
Six different types of service
43
Service Primitives (Operations)
Five service primitives for implementing a simple connection-oriented service
A service is formally defined by a set of primitives (operations) available to a user process to access the services
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
33
Network Software
bull Protocol Hierarchies (Layer structure)bull Design Issues for the Layersbull Connection-Oriented and Connectionless Servicesbull Service Primitivesbull The Relationship of Services to Protocols
34
Network Software
Protocol Hierarchiesndash a series of layers (levels)
ndash lower layer provides service to higher layers
ndash protocol bull an agreement between the communication parties on how
communication is to proceed
ndash Peers bull the corresponding layers on different machines
ndash Network architecture a set of layers and protocols
ndash Protocol stack bull a list of protocols used by a certain system one protocol per
layer
35
Network SoftwareProtocol Hierarchies
Layers protocols and interfaces
Peer
Network Architecture A set of layers and protocols Protocol Stack A list of protocols used by a certain system one protocol per layer
Virtual Communication
PhysicalCommunication
36
Layering
To make things simple modularization
Different layer has different functions
Create layer boundary such that description of services can be small number of interactions across boundary are minimized potential for interface standardized
Different level of abstraction in the handling of data (eg syntax semantics)
Provide appropriate services to upper layer
Use service primitives of lower layer
Network Software
37
Protocol Hierarchies (2)
The philosopher-translator-secretary architecture
38
Protocol Hierarchies (3)
Example information flow supporting virtual communication in layer 5
Message segmentation Encapsulation
39
Design Issues for the Layers
bull Addressing (telephone number e-mail address IP addresshellip)
bull Error Control (error correction codes ARQ HARQhellip)bull Flow Control (feedback-based rate-based)bull Multiplexing (gathering several small messages with the
same destination into a single large message or vice versa Demultiplexing)
bull Routing (directing traffic to the destination)
40
Design Issues for Layers
Identify senders and receivers ndash multiple computers and processes addressing
Data transferndash simplex half-duplex full-duplex communication
ndash of logical channels per connections priorities Error control
ndash error detection
ndash error correction Sequencing of pieces
41
Design Issues for Layers Flow control
ndash feedback from the receiver
ndash agreed upon transmission rate Length of messages
ndash long messages disassemble transmit and reassmeble messages
ndash short messages gather several small messages Multiplexing and Demultiplexing
ndash when expensive to set up a separate connection
ndash needed in physical layer Routing split over two or more layers
ndash High level London -gt France or Germany -gt Rome
ndash Low level many available circuits
42
Connection-Oriented and Connectionless Services
Six different types of service
43
Service Primitives (Operations)
Five service primitives for implementing a simple connection-oriented service
A service is formally defined by a set of primitives (operations) available to a user process to access the services
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
34
Network Software
Protocol Hierarchiesndash a series of layers (levels)
ndash lower layer provides service to higher layers
ndash protocol bull an agreement between the communication parties on how
communication is to proceed
ndash Peers bull the corresponding layers on different machines
ndash Network architecture a set of layers and protocols
ndash Protocol stack bull a list of protocols used by a certain system one protocol per
layer
35
Network SoftwareProtocol Hierarchies
Layers protocols and interfaces
Peer
Network Architecture A set of layers and protocols Protocol Stack A list of protocols used by a certain system one protocol per layer
Virtual Communication
PhysicalCommunication
36
Layering
To make things simple modularization
Different layer has different functions
Create layer boundary such that description of services can be small number of interactions across boundary are minimized potential for interface standardized
Different level of abstraction in the handling of data (eg syntax semantics)
Provide appropriate services to upper layer
Use service primitives of lower layer
Network Software
37
Protocol Hierarchies (2)
The philosopher-translator-secretary architecture
38
Protocol Hierarchies (3)
Example information flow supporting virtual communication in layer 5
Message segmentation Encapsulation
39
Design Issues for the Layers
bull Addressing (telephone number e-mail address IP addresshellip)
bull Error Control (error correction codes ARQ HARQhellip)bull Flow Control (feedback-based rate-based)bull Multiplexing (gathering several small messages with the
same destination into a single large message or vice versa Demultiplexing)
bull Routing (directing traffic to the destination)
40
Design Issues for Layers
Identify senders and receivers ndash multiple computers and processes addressing
Data transferndash simplex half-duplex full-duplex communication
ndash of logical channels per connections priorities Error control
ndash error detection
ndash error correction Sequencing of pieces
41
Design Issues for Layers Flow control
ndash feedback from the receiver
ndash agreed upon transmission rate Length of messages
ndash long messages disassemble transmit and reassmeble messages
ndash short messages gather several small messages Multiplexing and Demultiplexing
ndash when expensive to set up a separate connection
ndash needed in physical layer Routing split over two or more layers
ndash High level London -gt France or Germany -gt Rome
ndash Low level many available circuits
42
Connection-Oriented and Connectionless Services
Six different types of service
43
Service Primitives (Operations)
Five service primitives for implementing a simple connection-oriented service
A service is formally defined by a set of primitives (operations) available to a user process to access the services
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
35
Network SoftwareProtocol Hierarchies
Layers protocols and interfaces
Peer
Network Architecture A set of layers and protocols Protocol Stack A list of protocols used by a certain system one protocol per layer
Virtual Communication
PhysicalCommunication
36
Layering
To make things simple modularization
Different layer has different functions
Create layer boundary such that description of services can be small number of interactions across boundary are minimized potential for interface standardized
Different level of abstraction in the handling of data (eg syntax semantics)
Provide appropriate services to upper layer
Use service primitives of lower layer
Network Software
37
Protocol Hierarchies (2)
The philosopher-translator-secretary architecture
38
Protocol Hierarchies (3)
Example information flow supporting virtual communication in layer 5
Message segmentation Encapsulation
39
Design Issues for the Layers
bull Addressing (telephone number e-mail address IP addresshellip)
bull Error Control (error correction codes ARQ HARQhellip)bull Flow Control (feedback-based rate-based)bull Multiplexing (gathering several small messages with the
same destination into a single large message or vice versa Demultiplexing)
bull Routing (directing traffic to the destination)
40
Design Issues for Layers
Identify senders and receivers ndash multiple computers and processes addressing
Data transferndash simplex half-duplex full-duplex communication
ndash of logical channels per connections priorities Error control
ndash error detection
ndash error correction Sequencing of pieces
41
Design Issues for Layers Flow control
ndash feedback from the receiver
ndash agreed upon transmission rate Length of messages
ndash long messages disassemble transmit and reassmeble messages
ndash short messages gather several small messages Multiplexing and Demultiplexing
ndash when expensive to set up a separate connection
ndash needed in physical layer Routing split over two or more layers
ndash High level London -gt France or Germany -gt Rome
ndash Low level many available circuits
42
Connection-Oriented and Connectionless Services
Six different types of service
43
Service Primitives (Operations)
Five service primitives for implementing a simple connection-oriented service
A service is formally defined by a set of primitives (operations) available to a user process to access the services
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
36
Layering
To make things simple modularization
Different layer has different functions
Create layer boundary such that description of services can be small number of interactions across boundary are minimized potential for interface standardized
Different level of abstraction in the handling of data (eg syntax semantics)
Provide appropriate services to upper layer
Use service primitives of lower layer
Network Software
37
Protocol Hierarchies (2)
The philosopher-translator-secretary architecture
38
Protocol Hierarchies (3)
Example information flow supporting virtual communication in layer 5
Message segmentation Encapsulation
39
Design Issues for the Layers
bull Addressing (telephone number e-mail address IP addresshellip)
bull Error Control (error correction codes ARQ HARQhellip)bull Flow Control (feedback-based rate-based)bull Multiplexing (gathering several small messages with the
same destination into a single large message or vice versa Demultiplexing)
bull Routing (directing traffic to the destination)
40
Design Issues for Layers
Identify senders and receivers ndash multiple computers and processes addressing
Data transferndash simplex half-duplex full-duplex communication
ndash of logical channels per connections priorities Error control
ndash error detection
ndash error correction Sequencing of pieces
41
Design Issues for Layers Flow control
ndash feedback from the receiver
ndash agreed upon transmission rate Length of messages
ndash long messages disassemble transmit and reassmeble messages
ndash short messages gather several small messages Multiplexing and Demultiplexing
ndash when expensive to set up a separate connection
ndash needed in physical layer Routing split over two or more layers
ndash High level London -gt France or Germany -gt Rome
ndash Low level many available circuits
42
Connection-Oriented and Connectionless Services
Six different types of service
43
Service Primitives (Operations)
Five service primitives for implementing a simple connection-oriented service
A service is formally defined by a set of primitives (operations) available to a user process to access the services
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
37
Protocol Hierarchies (2)
The philosopher-translator-secretary architecture
38
Protocol Hierarchies (3)
Example information flow supporting virtual communication in layer 5
Message segmentation Encapsulation
39
Design Issues for the Layers
bull Addressing (telephone number e-mail address IP addresshellip)
bull Error Control (error correction codes ARQ HARQhellip)bull Flow Control (feedback-based rate-based)bull Multiplexing (gathering several small messages with the
same destination into a single large message or vice versa Demultiplexing)
bull Routing (directing traffic to the destination)
40
Design Issues for Layers
Identify senders and receivers ndash multiple computers and processes addressing
Data transferndash simplex half-duplex full-duplex communication
ndash of logical channels per connections priorities Error control
ndash error detection
ndash error correction Sequencing of pieces
41
Design Issues for Layers Flow control
ndash feedback from the receiver
ndash agreed upon transmission rate Length of messages
ndash long messages disassemble transmit and reassmeble messages
ndash short messages gather several small messages Multiplexing and Demultiplexing
ndash when expensive to set up a separate connection
ndash needed in physical layer Routing split over two or more layers
ndash High level London -gt France or Germany -gt Rome
ndash Low level many available circuits
42
Connection-Oriented and Connectionless Services
Six different types of service
43
Service Primitives (Operations)
Five service primitives for implementing a simple connection-oriented service
A service is formally defined by a set of primitives (operations) available to a user process to access the services
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
38
Protocol Hierarchies (3)
Example information flow supporting virtual communication in layer 5
Message segmentation Encapsulation
39
Design Issues for the Layers
bull Addressing (telephone number e-mail address IP addresshellip)
bull Error Control (error correction codes ARQ HARQhellip)bull Flow Control (feedback-based rate-based)bull Multiplexing (gathering several small messages with the
same destination into a single large message or vice versa Demultiplexing)
bull Routing (directing traffic to the destination)
40
Design Issues for Layers
Identify senders and receivers ndash multiple computers and processes addressing
Data transferndash simplex half-duplex full-duplex communication
ndash of logical channels per connections priorities Error control
ndash error detection
ndash error correction Sequencing of pieces
41
Design Issues for Layers Flow control
ndash feedback from the receiver
ndash agreed upon transmission rate Length of messages
ndash long messages disassemble transmit and reassmeble messages
ndash short messages gather several small messages Multiplexing and Demultiplexing
ndash when expensive to set up a separate connection
ndash needed in physical layer Routing split over two or more layers
ndash High level London -gt France or Germany -gt Rome
ndash Low level many available circuits
42
Connection-Oriented and Connectionless Services
Six different types of service
43
Service Primitives (Operations)
Five service primitives for implementing a simple connection-oriented service
A service is formally defined by a set of primitives (operations) available to a user process to access the services
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
39
Design Issues for the Layers
bull Addressing (telephone number e-mail address IP addresshellip)
bull Error Control (error correction codes ARQ HARQhellip)bull Flow Control (feedback-based rate-based)bull Multiplexing (gathering several small messages with the
same destination into a single large message or vice versa Demultiplexing)
bull Routing (directing traffic to the destination)
40
Design Issues for Layers
Identify senders and receivers ndash multiple computers and processes addressing
Data transferndash simplex half-duplex full-duplex communication
ndash of logical channels per connections priorities Error control
ndash error detection
ndash error correction Sequencing of pieces
41
Design Issues for Layers Flow control
ndash feedback from the receiver
ndash agreed upon transmission rate Length of messages
ndash long messages disassemble transmit and reassmeble messages
ndash short messages gather several small messages Multiplexing and Demultiplexing
ndash when expensive to set up a separate connection
ndash needed in physical layer Routing split over two or more layers
ndash High level London -gt France or Germany -gt Rome
ndash Low level many available circuits
42
Connection-Oriented and Connectionless Services
Six different types of service
43
Service Primitives (Operations)
Five service primitives for implementing a simple connection-oriented service
A service is formally defined by a set of primitives (operations) available to a user process to access the services
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
40
Design Issues for Layers
Identify senders and receivers ndash multiple computers and processes addressing
Data transferndash simplex half-duplex full-duplex communication
ndash of logical channels per connections priorities Error control
ndash error detection
ndash error correction Sequencing of pieces
41
Design Issues for Layers Flow control
ndash feedback from the receiver
ndash agreed upon transmission rate Length of messages
ndash long messages disassemble transmit and reassmeble messages
ndash short messages gather several small messages Multiplexing and Demultiplexing
ndash when expensive to set up a separate connection
ndash needed in physical layer Routing split over two or more layers
ndash High level London -gt France or Germany -gt Rome
ndash Low level many available circuits
42
Connection-Oriented and Connectionless Services
Six different types of service
43
Service Primitives (Operations)
Five service primitives for implementing a simple connection-oriented service
A service is formally defined by a set of primitives (operations) available to a user process to access the services
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
41
Design Issues for Layers Flow control
ndash feedback from the receiver
ndash agreed upon transmission rate Length of messages
ndash long messages disassemble transmit and reassmeble messages
ndash short messages gather several small messages Multiplexing and Demultiplexing
ndash when expensive to set up a separate connection
ndash needed in physical layer Routing split over two or more layers
ndash High level London -gt France or Germany -gt Rome
ndash Low level many available circuits
42
Connection-Oriented and Connectionless Services
Six different types of service
43
Service Primitives (Operations)
Five service primitives for implementing a simple connection-oriented service
A service is formally defined by a set of primitives (operations) available to a user process to access the services
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
42
Connection-Oriented and Connectionless Services
Six different types of service
43
Service Primitives (Operations)
Five service primitives for implementing a simple connection-oriented service
A service is formally defined by a set of primitives (operations) available to a user process to access the services
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
43
Service Primitives (Operations)
Five service primitives for implementing a simple connection-oriented service
A service is formally defined by a set of primitives (operations) available to a user process to access the services
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
44
Service Primitives (2)
Packets sent in a simple client-server interaction on a connection-oriented network
If the protocol stack is located in the operating system
the primitives are normally system calls
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
45
Services to Protocols Relationship
The relationship between a service and a protocol
middotThe service defines what operations the layer is prepared to perform on behalf of its users
middotA service is a set of primitives that a layer provides to the layer above it
middotA protocol is a set of rules governing the format and meaning of the packets which areexchanged by the peer entities in the same layer
Service Providers
Service Users
Services related to the interfaces between layers Protocols related to the packets sent between peer entities on different machine
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
46
Reference Models
bull The OSI Reference Model
bull The TCPIP Reference Model
bull A Comparison of OSI and TCPIP
bull A Critique of the OSI Model and Protocols
bull A Critique of the TCPIP Reference Model
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
47
The design principle of the OSI reference model
bull A layer should be created where a different abstraction is needed
bull Each layer should perform a well defined functionbull The function of each layer can be chosen as an
international standardbull The layer boundaries should be chosen to
minimize the information flow across the interfaces
bull The number of layers should be not too large or not too small
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
48
Reference Models
The OSI reference model
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
49
The functions of the seven layersbull The physical layer is concerned with transmitting raw bits over a
communication channelbull The data link layer performs flow control and also transforms a
raw transmission facility into a line that appears error free (ARQ)bull The network layer controls the operation of the subnet eg
routing flow control internetworkinghellipbull The transport layer performs assembling and disassembling
isolates the upper layers from the changes in the network hardware and determines the type of services
bull The session layer establishes sessions (dialog control hellip)bull The presentation layer is concerned with the syntax and semanticsbull The application layer contains a variety of commonly used
protocols (eg Hyper Text Transfer Protocol for WWW file transfer e-mail network newshellip)
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
50
Reference Models (2)
The TCPIP reference model
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
51
Reference Models (3)
Protocols and networks in the TCPIP model initially
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
52
Comparing OSI and TCPIP Models
Concepts central to the OSI modelbull Services defines layerrsquos semantics
bull Interfaces tells the processes above it how to access it
bull ProtocolsProbably the biggest contribution of the OSI model is to make the
distinction between these three concepts explicit
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
53
A Critique of the OSI Model and Protocols
Why OSI did not take over the world
bull Bad timing
bull Bad technology
bull Bad implementations
bull Bad politics
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
54
Bad Timing
The apocalypse of the two elephants
new discovery
investment opportunity
right time to make
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
55
Bad Technology
bull The choice of seven layers was political
- session and presentation layers are nearly empty
- Data and network layers are overfull
bull The OSI model is extraordinarily complex
bull Some functions eg addressing flow control error control reappear again and again
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
56
Bad Implementations
bull Huge Unwieldy and Slow
Bad Politicsbull Bureaucrats involved too much (European
telecommunication ministries community us government)
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
57
A Critique of the TCPIP Reference Model
Problemsbull Service interface and protocol not distinguishedbull Not a general modelbull Host-to-network ldquolayerrdquo not really a layer (is an interface)bull No mention of physical and data link layersbull Minor protocols deeply entrenched hard to replace
(The virtual terminal protocol TELNET was designed for mechanical teletype terminal)
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
58
Hybrid Model
The hybrid reference model to be used in this book
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
59
Example Networks
bull The Internet
bull Connection-Oriented Networks X25 Frame Relay and ATM
bull Ethernet
bull Wireless LANs 80211
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
60
The ARPANET
(a) Structure of the telephone system(b) Baranrsquos proposed distributed switching system
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
61
1048576
Original backbone of Internet
Wide area network around which TCPIP was developed Funding from Advanced Research Project Agency1048576 Initial speed 50 Kbps
ARPANET (1969-1989)
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
62
The ARPANET (2)
The original ARPANET design
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
63
The ARPANET (3)
Growth of the ARPANET (a) December 1969 (b) July 1970(c) March 1971 (d) April 1972 (e) September 1972
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
64
NSFNET
The NSFNET backbone in 1988
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
65
Funded by National Science Foundation1048576 Motivation Internet backbone to connect all scientists and engineers1048576 Introduced Internet hierarchy ndash Wide area backbone spanning geographic US ndash Many mid-level (regional) networks that attach to backbone ndash Campus networks at lowest level1048576 Initial speed 1544 Mbps
NSFNET (1987-1992)
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
66
Internet Usage
Traditional applications (1970 ndash 1990)
bull E-mail
bull News
bull Remote login
bull File transferWorld Wide Web changed all that and brought millions of new
nonacademic users
Internet Service Providers (ISP) offer individual users at home the ability to call up one of their machines and connect to the Internet to access all kinds of services
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
67
Architecture of the Internet
Overview of the Internet
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
68
ATM Virtual Circuits
A virtual circuit
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
69
ATM Virtual Circuits (2)
An ATM cell
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
70
The ATM Reference Model
The ATM reference model
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
71
The ATM Reference Model (2)
The ATM layers and sublayers and their functions
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
72
Ethernet
Architecture of the original Ethernet
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
73
Wireless LANs
(a) Wireless networking with a base station(b) Ad hoc networking
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
74
Wireless LANs (2)
The range of a single radio may not cover the entire system
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
75
Wireless LANs (3)
A multicell 80211 network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
76
Network Standardization
bull Whorsquos Who in the Telecommunications Worldbull Whorsquos Who in the International Standards Worldbull Whorsquos Who in the Internet Standards World
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
77
Telecommunication International Telecommunication Union (ITU) Telecommunications Standardization Sector (ITU-T)
International Standard International Standards Organization (ISO) ANSI (USA) ETSI (Europe) BSI (Great Britain) AFNOR(France) IEEE
Internet Standard Internet Activities Board (IAB 1983) Internet Research Task Force (IRTF) Internet Engineering Task Force (IETF) Request for Comments (RFC) httpcache2cisnctuedutwDocumentsrfc ftpftpmeriteduinternetdocumentsrfc Internet Draft Standard Internet Standard
Standard Organizations
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
78
ITU
bull Main sectorsbull Radiocommunicationsbull Telecommunications Standardizationbull Development
bull Classes of Membersbull National governmentsbull Sector membersbull Associate membersbull Regulatory agencies
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
79
IEEE 802 Standards
The 802 working groups The important ones are marked with The ones marked with are hibernating The one marked with dagger gave up
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
80
Metric Units
The principal metric prefixes
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
81
1969 ARPANET
1970rsquos ALOHA Ethernet DECNet SNA
1980rsquos Proliferation of LAN (Ethernet Token Ring)
1987 High speed LANMAN (FDDI) BISDN (ATM)
1990 High speed WAN (NSFNET 45 Mbps)
1993 High speed Ethernet (Fast Ethernet EtherSwitch)
1996 Interent II (622Mbps)
1998 Gigabit Ethernet
History of Networking
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
82
TANET 199112 64Kbps 199212 256Kbps 199410 512Kbps 199512 T1 19975 T3 Current Status T3 to USA by the end of 1998 (Policy routing enforced) T3 backbone around the island Add a T3 from MOE to CCU Internet II (19996)
HiNet (1994) SeedNet(數位聯合股份公司 )
History of Taiwanrsquos Network
![Art history1stweek [โหมดความเข้ากันได้] · PDF fileMesopotamian Art-today Classical Age Medieval Age Renaissance Art 16th-18th century 18th-19th](https://img.pdfslide.tips/doc/110x75/5a9ec01a7f8b9a62178bc041/art-history1stweek-art-today.jpg)
