1. 網路概論 Class 1-Protocols, Architecture and Transmission Media 授課老師 楊人順 2001/09/26

2. -2- Presentation Outlines Network Classifications Network Devices Network Software Network Topologies Network Protocols Switching Techniques Group Discussion

3. -3- Network Classification in terms of transmission technology Switch (Inter-media) Network –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

4. -4- 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

5. -5- 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

6. -6- Network Software 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。 Network Game Video-on-Demand( 隨選視訊 ) Video-Conference( 視訊會議 ) Point-of-Sale(POS) accounting

7. -7- Network Topologies Point-to-point Multipoint Broadcast Switched Network Internet (please referred as page 34 Figure 2.1)

8. -8- 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) 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

9. -9- Why standardization Standard protocol

10. -10- Three Layer Protocol Model Application Transport Network Access Application Transport Network Access Communications Network Application protocol Transport protocol Network access protocol Network access protocol A simplified layer model

11. -11- 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)

12. -12- 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)

13. -13- OSI Reference layers

14. -14- Transmission Control Protocol/Internet Protocol (TCP/IP) Application TCP IP Network access Physical Subnet : Hardware and Firmware Packet operations : addressing/routing, p-t-p link management and network resource managements connection operations : end-to-end connection maintained, flow/error control and connection resource managements Socket Interface (OSI v.s. TCP/IP : pp.22 Figure 1.11) (pp.59 Application protocols by using TCP/IP as platform)

15. -15- OSI v.s. TCP/IP

16. -16- Protocol Data Units (PDUs) Segment/Reassembly Application data (application PDU) Transport SDU Network SDU Transport header Transport header Network header Network header Transport PDU Network PDU

17. -17- 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

18. -18- Addressing Concepts

19. -19- Address Modes DestinationNetwork AddressSystem AddressPort/SAP Address UnicastIndividual Group MulticastIndividualAllGroup All Group Individual All BroadcastIndividualAll

20. -20- Switching Techniques Circuit Switch Message Switch Packet Switch Virtual Packet Switch

21. Group Discussion