1. Network = Net + Work What is flowing ? What different forms flow ? What rules govern flow ? Where does the flow occur ?

2. Data Network What is flowing ? –Data What different forms flow ? –Text, Graphic, Video... What rules govern flow ? –Standard, Protocol... Where does the flow occur ? –Wire, Cable, Atmosphere...

3. Evolution of Networking (1) Individual Computers

4. Evolution of Networking (2) Duplicate equipment and resources Difficult to communicate Difficult to provide management

5. Evolution of Networking (3) LAN: Local Area Network

6. Evolution of Networking (4) WAN: Wide Area Network

7. LAN = Local Area Network 高速、低錯誤率且涵蓋較小地理範 圍 ( 到數千公尺 ) 的數據網路 可連接在同一大樓或地理限制內的 工作站、周邊設備、終端機和其他 設備等。 LAN 的標準指定了纜線，以及 OSI 模型之實體和資料鏈結層的傳訊。 乙太網路、 FDDI 、記號環網路都是 廣泛被使用的 LAN 技術。 全時段連線

8. LAN Equipment: Repeater Regenerates and Repeats the signal.

9. LAN Equipment: HUB Multiport Repeater

10. LAN Equipment: Bridge Filter traffic based on MAC Addresses.

11. LAN Equipment: Switch Multiport Bridge

12. LAN Equipment: Router Path determination Packet switching

13. WAN = Wide Area Network 服務廣大區域使用者的資料通訊網路，通常使用電信 公司所提供的傳輸設備。 訊框中繼、 SMDS 和 X.25 等都是廣域網路的實例。 頻寬較低 ( 與 LAN 比較 ) 全時段或部分時段

14. WAN Media: ISDN & PSTN Part-time connectivity (Dial-up by modem)

15. WAN Media: Frame Relay Full-time connectivity

16. WAN Media: Leased Line Full-time connectivity

17. WAN Equipment: Modem MODEM = MOdulate and DEModulate Syn Modem, Asyn Modem

18. WAN Equipment: Comm. Server Remote Access Server

19. WAN Equipment: WAN Switch Frame Relay switch

20. WAN Equipment: Router LAN and WAN connectivity

21. MAN= metropolitan-area network MAN - 大都會區域網路 (metropolitan- area network) 。 擴展至大都會區域的網路。 MAN 所擴展的區域會大於 LAN ，但小於 WAN 。

22. Digital Bandwidth How much information can flow from one place to another in a given amount of time.

23. Comparing Speed & Distance MediaBandwidthDistance 10Base210-100Mbps185m 10Base510-100Mbps500m 10BaseT10Mbps100m 100BaseTX100Mbps100m 100Base-FX100Mbps2000m 1000Base-LX1000Mbps3000m

24. Analogy for Bandwidth: Pipe

25. Analogy for Bandwidth Brainstorming Highway Radio system

26. Highway Analogy for Bandwidth

27. Audio Analogy for Bandwidth

28. When we say our Lab is capable of 100Mbps, what do we call that speed? Bandwidth Do we get the full 100Mbps? No! What do we call what we actually get? Throughput

29. 資訊抵達或經過網路系統中的某一特定點的速率 The throughput is effected by: –Internetworking devices –Type of data being transferred –Topology –Number of users –User's computer –Server computer –Power and weather-induced outages <= Bandwidth

30. Time Calculations

31. The importance of Bandwidth Finite Save money A key measure of network performace A key to understanding the Internet Increases constantly

32. Maximum Bandwidths and Length Limitations Typical MediaMax. Theoretical Bandwidth Max. Physical Distance 50-Ohm coaxial cable (thinnet) 10-100 Mbps185m 75-Ohm coaxial cable (thicknet) 10-100 Mbps500m CAT5 UTP10 Mbps100m CAT 5 (Fast Ethernet)100 Mbps100m Multimode Fiber100 Mbps2000m Singlemode Fiber1000 Mbps (1 Gbps)3000m Wireless11 MbpsA few hundred meters

33. WAN Services and Bandwidths Type of Service Typical UserBandwidth ModemIndividuals56 Kbps ISDNTelecommuters and small businesses128 Kbps Frame RelaySmall institutions and reliable WANs 56 Kbps to 1544 Mbps T1Larger entities1.544 Mbps T3Larger entities44.736 Mbps STS-1 (OC-1)Phone companies/Backbones51.840 Mbps STS-3 (OC-3)Phone companies/Backbones155.251 Mbps STS-48 (OC-48) Phone companies/Backbones 2.488320 Gbps