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

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

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

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

Why do we network computers?

Basic Terms Clients Peers Servers

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.

Network Types Server-based Peer to Peer Hybrid

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

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

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

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

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

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

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

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

Would a Peer Network be good for the Collections Agency?

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

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

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

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

Client Hardware 486 or better 4MB of RAM or better

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?

Network Topologies Bus Ring Star Mesh

Bus Networks

Ring Networks

Star Networks

Mesh Networks

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?

Network Media Copper Glass Air Radio

Copper Properties:

Glass Properties:

Air Properties:

Radio Properties:

Network protocols: Hardware protocols Hardware-software protocols Software protocols

Decision Tree for Networks- Network Type

Decision Tree for Servers

Decision Tree for Topologies

Decision Tree for Media