Download 網路概論 Class 1-Protocols, Architecture and Transmission Media

網路概論
Class 1-Protocols, Architecture and
Transmission Media
授課老師
楊人順
2001/09/26
Presentation Outlines
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Network Classifications
Network Devices
Network Software
Network Topologies
Network Protocols
Switching Techniques
Group Discussion
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Network Classification in terms of
transmission technology
• Switch (Inter-media) Network
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Circuit-Switched Network
Message-Switched Network
Packet-Switched Network
Virtual Packet-Switched Network
• Broadcast (non-inter-media) Network
– LAN: Ethernet 10BASE5 and 10BASE2
– Packet Radio Network
– Satellite Network
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Network classification in term of
scale
• Local Area Network (LAN)
– Ethernet, Ether-switch
– Token Ring, Token Bus
– ATM LAN, Wireless LAN
• Metropolitan Area Network
– DQDB
• Wide Area Network
– ISDN, B-ISDN, Internet
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Network Devices
• Repeater : electronically repeating (信號放大/電氣層隔離)
(layer 1)
• Bridge : only to connect LANs with different/some
protocol (實際地址登記辨識/資料流隔離)(layer 2)
• Router : Connect different Network (LAN, MAN, WAN)
and routing + protocol transformation (layer 3)
• Gateway : Connect different Network (WAN-to-WAN) and
protocol transformation (layer 3 or layer 4-7)
• Wireless Devices : wireless Hubs for LAN and Mobile
communication systems
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Network Software
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Telnet
FTP
Email
WWW
Teleshopping (SET-Secure Electronic Transactions安全電
子交易)
– 它是一個用來保護在任何網路上付款卡交易的開放式規格。
SET規格融合了從RSA資料安全的公開鑰匙(Public Key)編成密
碼文件(Cryptography)的使用，以保護任何開放型網路上個人
和金融資訊的隱密性。
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Network Game
Video-on-Demand(隨選視訊)
Video-Conference(視訊會議)
Point-of-Sale(POS) accounting
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Network Topologies
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Point-to-point
Multipoint Broadcast
Switched Network
Internet
(please referred as page 34 Figure 2.1)
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Network Protocols
• What is a Protocol ?
– A communication language between one-to-one or
among many computers in hardware or software.
– Why standardization ? (next slide)
– Functions (pp.35-44)
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Encapsulation
Segmentation and reassembly
Connection control (pp.38 Figure 2.3)
Ordered delivery
Flow control
Error control
Addressing (pp. 41 Figure 2.4) and addressing modes (pp. 42
Table 2.1)
• Multiplexing
• Transmission services
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Why standardization
Standard
protocol
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Three Layer Protocol Model
Application protocol
Application
Transport protocol
Transport
Network Access
Application
Transport
Communications
Network access
Network access
Network
protocol
Network Access
protocol
A simplified layer model
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Why Layering
• Discussion :
– Design: separate layers to handle different function, and
collect similar functions into the same layer
– Maintain: errors are easier to be located, each layer
boundaries with its upper and lower layer only
– Replace: allow changes without affecting other layers
– software engineering issues
• Principles Used in Defining the OSI layers
– (pp. 45 Table 2.2)
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Open System Interconnection
(OSI)
• Developed by International Organization for
Standardization.
• A reference model for current and future protocols
• Layers Descriptions (three layer model  OSI)
– Network access  Physical, Data link and Network
layers
– Transport  Transport and Session layers
– Application  Presentation and Application layers
• OSI layer on network equipments (next slide)
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OSI Reference layers
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Transmission Control
Protocol/Internet Protocol (TCP/IP)
Application
TCP
IP
Network access
(pp.59 Application protocols by using TCP/IP as platform)
Socket Interface
connection operations : end-to-end connection
maintained, flow/error control and connection
resource managements
Packet operations : addressing/routing, p-t-p link
management and network resource managements
Subnet : Hardware and Firmware
Physical
(OSI v.s. TCP/IP : pp.22 Figure 1.11)
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OSI v.s. TCP/IP
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Protocol Data Units (PDUs)
Segment/Reassembly
Application data (application PDU)
Transport
header
Transport
header
Transport SDU
Transport SDU
Transport PDU
Transport PDU
Network PDU
Network PDU
Network SDU
Network
header
Network SDU
Network
header
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Why add Header and Tailor
• Addressing (next slide)
• Synchronization : Intra-Connection and
Inter-Connection synchronization
• Flow and Error Control (Quality of Service)
• Other controls : packetization information
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Addressing Concepts
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Address Modes
Destination
Network Address
System Address
Port/SAP Address
Unicast
Individual
Individual
Individual
Individual
Individual
Group
Individual
All
Group
All
All
Group
Individual
Individual
All
Individual
All
All
All
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All
Multicast
Broadcast
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Switching Techniques
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Circuit Switch
Message Switch
Packet Switch
Virtual Packet Switch
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Group Discussion