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OSI Reference Model
V1.0
Data Customer Service Dept.
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Course Objectives
Grasp the basic knowledge of network
Understand network evolution history and classification ofnetwork
Know standardization organizations in data communication
field Grasp OSI model and each layers function
Grasp the function of different kind of network devices and itsposition
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Course Outline
Chapter I Network Overview
Chapter II OSI Reference Model
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Course Contents
Chapter I Network Overview
Section 1 Definition and Evolution History of Network
Section 2 Classification of Network
Section 3 Network Topology
Section 4 International Standardization Organizations
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Definition of Network
Computer network refers to interconnect the separately distributedcomputers and external communication lines to form a system for
easy info exchanging and resource sharing among multiple pieces of
computers.
IP HotelMobile
Server SOHO
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Network Evolution History
Phase 270s 80s
Phase 4 80s till now
Phase 1 50s 60s
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Course Contents
Chapter I Network Overview
Section 1 Definition and Evolution History of Network
Section 2 Classification of Network
Section 3 Network Topology
Section 4 International Standardization Organizations
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Classification of Network
Local Area Network (LAN)
Metro Area Network (MAN)
Wide Area Network (WAN)
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LAN
LAN usually covers an area of several kilometers and integrated
several independent data devices to enable users to share
network resources.
Features: short distance, low latency, high data-transmitting rate
and reliable transmission.
The infrastructures of LAN include servers, clients, network
equipments and communication media.
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MAN
MAN usually covers an area of several kilometers to
hundreds of kilometers
Data transmission rate ranged from several Kbit/s to several
Gbit/s
Optical fiber is the best transmission media of MAN
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WAN
WAN is mainly used to connect LANs, and provide data
communication within wide areas.
WAN covers an area of hundreds to thousands of
kilometers.
Classification of WAN:
ISDN
DDN
X.25 packet switching networkFrame Relay
ATM
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Course Contents
Chapter I Network Overview
Section 1 Definition and Evolution History of Network
Section 2 Classification of Network
Section 3 Network Topology
Section 4 International Standardization Organizations
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Network Topology
Star Topology
Tree Topology
Distributed Topology
Ring Topology
Bus Topology
Hybrid Topology
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Course Contents
Chapter I Network Overview
Section 1 Definition and Evolution History of Network
Section 2 Classification of Network
Section 3 Network Topology
Section 4 International Standardization Organizations
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Standardization Organizations
International Organization for Standardization (ISO)
International Telecommunications Union (ITU)
Institute of Electrical and Electronics Engineering (IEEE)
American National Standard Institute (ANSI)
Electronic Industries Association/ Telecommunication
Industry Association (EIA / TIA)
Internet Engineering Task Force (IETF)Internet Architecture Board (IAB)
Internet Assigned Numbers Authority (IANA)
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Course Contents
Chapter II OSI Reference Model
Section 1 OSI Model Overview
Section 2 Physical Layer
Section 3 Data-link Layer
Section 4 Network Layer
Section 5 Transport Layer
Section 5 Session/Presentation/Application Layer
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OSI Reference Model Overview
Data Transmission
between Networks
Transport Layer
Data-link Layer
Network Layer
Physical Layer
Data Transmission
between HostsSession Layer
Presentation Layer
Application Layer
OSI RMOpen System Interconnection Reference Model
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Functions of Each Layer
1
2
3
4
5
6
7Provide communication between
application programs
Process data format and encryption
Establish, maintain and manage sessions
Establish end-to-end connection
Addressing and routing
Provide media access and linkmanagement
Bit stream transmission
Transport Layer
Data-link Layer
Physical Layer
Session Layer
Presentation Layer
Application Layer
Network Layer
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Relationship between Each Layer of OSI Model
Only peer layers with same protocol are able to communicate.
Transport Layer
Data-link Layer
Network Layer
Physical Layer
Session Layer
Presentation Layer
Application LayerAPDU
Bits
Frame
Packet
Segment
SPDU
PPDU
Transport Layer
Data-link Layer
Network Layer
Physical Layer
Session Layer
Presentation Layer
Application Layer
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Upper Layer Data
Upper Layer DataTCP Header
IP Header
LLC Header
0101110101001000010
MAC Header
Segment
Packet
Bits
Frame
PDU
FCS
FCS
Data Encapsulation
Transport
Layer
Data-link Layer
Physical
Layer
Network
Layer
Presentation LayerApplication Layer
Session Layer
Upper Layer Data
Upper Layer Data
Upper Layer Data
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Upper Layer Data
LLC Hdr + IP + TCP + Upper Layer Data
IP + TCP + Upper Layer Data
TCP+ Upper Layer Data
Upper Layer Data
0101110101001000010
Transport Layer
Data-link Layer
PhysicalLayer
NetworkLayer
Presentation Layer
Application Layer
Session Layer
Data De-encapsulation
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Study Contents
Chapter II OSI Reference Model
Section 1 OSI Model Overview
Section 2 Physical Layer
Section 3 Data-link Layer
Section 4 Network Layer
Section 5 Transport Layer
Section 5 Session/Presentation/Application Layer
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Physical Layer
EIA/TIA-232V.35Physical Layer
Moves bits between devices
Specified voltage, rate and pin-out cables
Physical Layer is the first and bottom layer of OSIReference Model.
Physical Layer mainly provides bit stream transmission.
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Physical Layer also defines:
Media Type
Connector Type
Signal Type
Function of Physical Layer
Ethernet
8
02.3
V.3
5
Physical
Layer
EIA/TIA-232
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HUB
Host
Host
10Base2Ethernet thin-wire
10Base5Ethernet thick-wire
10BaseTTP
Ethernet/802.3
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HUB works on Physical Layer
The work stations connected via HUB are physically Star
Topology but Bus Topology logically.
All devices are in one Collision Domain
The more terminals, the more collisions
All devices share the bandwidth
Collision Domainan assembling of all the workstations on the
same cable or of all the nodes on the same physical segment or a
group of nodes contending the same bandwidth.
HUB
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Study Contents
Chapter II OSI Reference Model
Section 1 OSI Model Overview
Section 2 Physical Layer
Section 3 Data-link Layer
Section 4 Network Layer
Section 5 Transport Layer
Section 5 Session/Presentation/Application Layer
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802.3 / 802.2
HDLC
EIA/TIA-232
V.35
Data-link Layer
Data-link
Layer
Combines packets into bytes and bytes to
frames
Provides access to media using MAC address
Performs error detection not correction
Physical
Layer
Moves bits between devices
Specified voltage, rate and pin-out cables
Data-link Layer is the second layer of OSI Reference Model
Mainly responsible to precisely transmit the data packet to Network
Layer of destination host.
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Data-link Layer defines:
Physical source and destination addresses
Associate SAP (service access point) to upper layer protocols
Define network topology
Control of frame order
Flow Control
data-
EIA/TIA-232
v.35
802.2
802.3
Function of Data-link Layer
Data-link
Physical
EIA/TIA-232
v.35
FR802.2
802.3
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DataSource
addressFCSLength
Destination
address
Variable Length266 4
00.d0.d0 xx.xx.xx
Distributed bymanufacturer
The manufacturercode assigned by
IEEE
Preamble
Ethernet II uses
Type in this
field.
MAC address
8# Bytes
MAC Address
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Layer 2 Switch and Bridge work on Data-link Layer
Each network segment connected to each port is an
individual Collision Domain
All network segments are in one Broadcast Domain
Broadcast Domainassembly of nodes that receive same
broadcast message, able to be classified into one logical network
segment with other broadcast nodes.
Switch/Bridge
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HUB Bridge Switch Router
Number ofCollision
Domain: 1 4 4 4
Number of
Broadcast
Domain:1 1 1 4
Collision Domain and Broadcast Domain
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Study Contents
Chapter II OSI Reference Model
Section 1 OSI Model Overview
Section 2 Physical Layer
Section 3 Data-link Layer
Section 4 Network Layer
Section 5 Transport Layer
Section 5 Session/Presentation/Application Layer
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Network Layer
EIA/TIA-232
V.35
IP
IPX
Network
Layer
Provides logic addressing which
routers use for path determination
Data-link
Layer
Combines packets into bytes and bytes to
frames
Provides access to media using MAC address
Performs error detection not correction
Physical
Layer
Moves bits between devices
Specifies voltage, rate and pin-out cables
802.3 / 802.2
HDLC
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Defines Logical
Address
Addressing andRouting
Network
LayerIP, IPX
Data-link
Layer
Physical
LayerEIA/TIA-232
v.35
HDLC
802.2
802.3
Functions of Network Layer
FR
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Network Layer address is globally unique, constituted
by two parts: Network address and Host address.
IP
address
IPXaddress
Network address Host address
10. 8.2.48
Network addressHost address
1aceb0b1. 0000.0c00.6e25
Logical Address(1)
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11111111 11111111 00000000 00000000
10101100 00010000 01111010 11001100
Binary Mask
Binary Address
172.16.122.204 255.255.0.0
172 16 122 204
255
Address Mask
255 0 0
Network Host
Logical Address(2)
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Functions:Logical routing
Select best routing path
Broadcast control
Multicast Control
Flow Control
Connected to WAN
Router
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Course Contents
Chapter II OSI Reference Model
Section 1 OSI Model Overview
Section 2 Physical Layer
Section 3 Data-link Layer
Section 4 Network Layer
Section 5 Transport Layer
Section 5 Session/Presentation/Application Layer
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TCP
UDP
SPX
802.3 / 802.2
HDLC
EIA/TIA-232
V.35
IP
IPX
Transport Layer
Transport
Layer
Provides reliable or unreliable delivery
Performs error correction before
retransmit
Network
Layer
Provides logical addressing,
which routers use for path determination
Data-link
Layer
Combines packets into bytes and bytes into frames
Provides access to media using MAC address
Performs error detection not correction
Physical
Layer
Moves bits between devices
Specifies voltage, rate, and pin-out cables
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Functions:
Segment Upper Layer Data
Establish end-to-end connection between application programs
Flow control
Connection-oriented and connectionless Communication
Network
Layer IPXIP
Transport
LayerSPXTCP UDP
Function of Transport Layer
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Synchronizing
Acknowledgement, Synchronizing
Acknowledgement
Data Transmission
Sender Receiver
Connection Established
Connection-oriented Session
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Course Contents
Chapter II OSI Reference Model
Section 1 OSI Model Overview
Section 2 Physical Layer
Section 3 Data-link Layer
Section 4 Network Layer
Section 5 Transport Layer
Section 5 Session/Presentation/Application Layer
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Session Layer
Transport
Layer
Provides reliable or unreliable delivery
Performs error correction before retransmit
Network
Layer
Provides logical addressing,
which routers use for path determination
Data-link
Layer
Combines packets into bytes and bytes into frames
Provides access to media using MAC address Performs error detection not correction
Physical
Layer
Moves bits between devices
Specifies voltage, rate, and pin-out cables
Keeps different applications data separateSession
Layer
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Presentation Layer
Presents data Handles processing such as encryption
PresentationLayer
TransportLayer
Provides reliable or unreliable delivery
Performs error correction before retransmit
Network
Layer
Provides logical addressing,
which routers use for path determination
Data-linkLayer
Combines packets into bytes and bytes into frames Provides access to media using MAC address
Performs error detection not correction
Physical
Layer
Moves bits between devices
Specifies voltage, rate, and pin-out cables
Keeps different applications data separateSession
Layer
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Provides a user interfaceApplication
Layer
Presents data
Handles processing such as encryption
Presentation
Layer
Transport
Layer
Provides reliable or unreliable delivery Performs error correction before retransmit
Network
Layer
Provides logical addressing,
which routers use for path determination
Data-link
Layer
Combines packets into bytes and bytes into frames Provides access to media using MAC address
Performs error detection not correction
Physical
Layer
Moves bits between devices
Specifies voltage, wire speed, and pin-out cables
Keeps different applications data separateSession
Layer
Application Layers
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Summary
Definition of Network
Network Evolution History
Classification of Networks
Network Topology Standardization Organizations in Data
Communication Field
OSI Model and Functions of Each Layer
Common Network Devices
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