1. CSC 363: Local Area Networks DePaul University Winter Quarter 1999 LoriLee M. Sadler

2. Intro to Course How to contact me Office Hours Course Components Schedule

3. Small Group Project 4 Cases from which to choose Final product Group registration on the web

4. The LAN Lab Access hours ID required What’s up there

5. Why do we network computers?

6. Basic Terms Clients Peers Servers

7. Problem: You’re installing a small network for a collections agency. There will be only five stations on the network. Cost is an issue, and the company would prefer not to dedicate an individual’s time to maintaining a network. However, the agency is also concerned about keeping its data safe, and the users are not sophisticated users.

8. Network Types Server-based Peer to Peer Hybrid

9. Server-Based Networks Also called client-server networks Servers –responsible for security and administration single login required for network resources –network services (e.g., printing, file storage) Clients –typically less powerful than servers –need client software to access network services

10. Domains Unique to server-based networks =>collections of networks and services that share security trust information Domain controllers handle security and permissions PDC=> BDC=>

11. Server-based Networks pros & cons Advantages –central security & admin –Optimized dedicated servers –Single-password security –Scales to large # of users Disadvantages –Dedicated servers are more expensive than plain old computers –Expensive NOS and clients –Requires dedicated sysadmin

12. Peer Networks Also called peer-to-peer networks No servers--every machine is a client and a server Users control access and security to each networked resource

13. Workgroups Typically grouped by users rather than by services or resources Password access to individual networked resources Peer machines not optimized for resource sharing

14. Peer Networks Pros and Cons Advantages –Cheap –Easy to set up –No sysadmin –Users control access & “Security” –No reliance on other computers Disadvantages –All advantages are also disadvantages –Inefficient use of peer equipment –Intrusive, easy to break security –Bad idea for large networks

15. Peer Security vs. Server Security Peer Security –One user or all users-- no user-level security –Each shared resource must have its own password –Lots of passwords means more points for hacking Server Security –Centrally managed security –Security controlled by groups of users and appropriate resources

16. Hybrid Networks Combines aspects of peer-to-peer and server networks All the advantages of server-based networks and most of peer-to-peer Some of the disadvantages of server-based networks

17. Would a Peer Network be good for the Collections Agency?

18. Would a Server-based Network be good for the Collections Agency?

19. Server types File Servers Print Servers Application Servers Message Servers Database Servers

20. Server Software Called Network Operating System (NOS) –Windows NT –Novell Netware Requires matching clients

21. Server Hardware Typically more powerful than a client NT requires a minimum of: –Pentium processor –16MB of RAM Reality Check –Pentium II –64-256MB RAM –Large hard drive

22. Client Hardware 486 or better 4MB of RAM or better

23. Problem: You are considering networking topologies for a network for a telemarketing firm. When would a ring network be appropriate? When would a star network be appropriate? When would a bus network be appropriate?

24. Network Topologies Bus Ring Star Mesh

25. Bus Networks

26. Ring Networks

27. Star Networks

28. Mesh Networks

29. Problem: You are designing a network for an office complex. Several buildings must be linked together with high-performance long-distance links, and servers within the building must be linked together with a high-speed backbone. Hundreds of clients computers in each building must be inked together inexpensively. What media will you use?

30. Network Media Copper Glass Air Radio

31. Copper Properties:

32. Glass Properties:

33. Air Properties:

34. Radio Properties:

35. Network protocols: Hardware protocols Hardware-software protocols Software protocols

36. Decision Tree for Networks- Network Type

37. Decision Tree for Servers

38. Decision Tree for Topologies

39. Decision Tree for Media