1. CHAPTER An Evolution of Physical Network Architectures

2. Chapter Objectives Discuss the different network hardware architectures that span varying sizes of business enterprises Provide an insight into LAN architectural evolution –Centralized, decentralized, mixed etc. Introduce the WAN architecture that is becoming increasingly relevant to the Internet

3. Chapter Modules Small Computer Networks Medium Sized Computer Networks Large Scale Computer Networks Enterprise Computer Networks Wide Area Networks

4. Chapter Focus on Functional Types Distributed –LAN driven –Current trend Centralized –Mini/Mainframe derived –Past trend and probably the future trend Combination –Distributed/ Centralized –Emerging trend

5. MODULE Small Computer Networks

6. Major Types Distributed –Resources and executions are distributed over the network –LAN Centralized –Resources and execution are confined to a central unit –Multi-user Micro A Unix multi-user computer operating under the Unix operating system –Entry-level minicomputers also known as departmental computers

7. LAN Evolution File Server Application Server (Client-Server Technology) Thin-Clients & Terminal Servers Distributed execution Cooperative execution Centralized execution Past Present Future Mainframe architecture of the past

8. IBM 9370 Virtual Machine Example

9. END OF MODULE

10. Suns Computer Network Sun Enterprise Server Pentium

11. Web Research Visit www.sun.com and obtain information about their Sun Enterprise serverswww.sun.com –How are they networked together? –Choose a server to serve 25 workstations Sun Enterprise Server 220REnterprise Server 220R

12. MODULE Medium Sized Computer Networks

13. Major Types Centralized architecture –Past, present and possible future –Minicomputers Decentralized architecture –Present –Very large LANs with Multiple segments Mixed architecture –Combination of both of the above –Large LAN with different network segments

14. Centralized Architecture: Medium Sized Computer Network AS 400 Micro OS 400 Token Ring OS2 / Warp

15. Web Research Visit www.ibm.com to obtain more information about the configuration of an AS 400 computer for:www.ibm.com –Running OS/400 –Functioning as a file server for a Windows net work Name the different IBM server families Visit www.search400.com for additional information on AS/400www.search400.com

16. Decentralized Architecture: A Switched LAN Ethernet Switch Client Ethernet LAN Segments Hub

17. END OF MODULE

18. MODULE Large-Scale Computer Networks

19. Types Centralized Architecture Decentralized Architecture Combination of both

20. Examples Mainframe computer –Centralized Heterogeneous LAN –Distributed

21. Large Scale Centralized Computer Network Concentrator Term. PC Pc Mainframe Front-end Processor DASD Hard Disk Modem Server

22. Mainframe Reference Terminology for Equipment DCE (Data Communication Equipment) –Front-end Processor, Modem Server and Concentrator for example DTE (Data Terminal Equipment) –Terminals, PCs and Printers for example

23. LAN Reference Terminology for Equipment Internetworking devices –Switches, Routers etc. Clients or Workstations –PCs

24. Heterogeneous LAN Architecture RouterSwitch WS Hub WS Server 3 Server 4 LANs With Servers/Minicomputers Server 1 Server 2

25. Switch Switch network traffic between the LAN segments Allows crossover traffic from one segment to another segment Otherwise, the network traffic is confined to the individual segments Used for connecting LAN segments that operate under the same protocol Performs Layer 2 functions –Newer switches may also perform some routing which is a Layer 3 functions Such switches are called Layer 3 switches

26. Router Used for connecting LAN segments that operate under different protocols A more advanced device compared to the switch Routes traffic between different LANs Performs Layer 3 functions

27. Web Research Visit www.whatis.com and get the definition for switches and gatewayswww.whatis.com Access www.cisco.com to obtain further information on the followingwww.cisco.com –Switch –Router

28. END OF MODULE

29. MODULE Enterprise Computer Networks

30. Major Types Centralized –Based on mainframes –Mainframe derived architecture Decentralized –Based on a backbone used of connecting LANs and other computer systems –LAN driven architecture

31. Enterprise Systems Network: Centralized Architecture Mainframe Front End Processor Mini- Computer Term. PC Concentrator LAN Modem Server Ter. External Lines Gateway

32. Enterprise Systems/Campus Network Fiber Optic Backbone (FDDI) Mainframe Systems Bus LAN Ring LAN Modem Gateway WAN Connection Star LAN

33. END OF MODULE

34. MODULE Wide Area Networks

35. Types By virtue of its definition, it is a decentralized network

36. Wide Area Network Overview Public Network (Frame Relay ATM, X.25) LANs Terminal or Microcomputer Campus Network Enterprise Systems Network Mainframe Systems

37. Web Research Access a reference website such as www.whatis.com to obtain information on the following www.whatis.com –ATM, Frame Relay, X.25 –DS1, DS3 etc. –T1, T3 etc. –OC1, OC3 etc. Switches and Routers

38. END OF MODULE

39. END OF MODULE END OF CHAPTER