Networks

Networks

1. Definition: Two or more computers that are linked together so that they are able to share resources.

2. Shared Resources

   • Hardware
     • Printers
     • Scanners
   • Software
   • Internet connection
   • Data

3. Peer to Peer Networks

   • Equal status
   • Share resources
   • Basic knowledge
   • Small/home
   • More people = speed decreases

4. Client - Server Network

   • Powerful computer = server
   • Server stores data, in control
   • Dependent on server
   • Programs stored on server

5. LAN

   • Local area network
     • Small area
     • Single building
     • Cheap to build and run
     • Uses cable, wireless, microwave and infrared

6. WAN

   • Wide Area Network
     • Wide geographical area
     • Lots of different buildings
     • Expensive telecommunication links
     • Expensive to build and run

7. Network Topologies

   • Star
     • +ve
       • Fault tolerant
       • Load tolerant
       • Easy to add extra devices
     • -ve
       • Higher cost
       • Dependence on server
   • Ring
     • +ve
       • Equal access
       • Easy to add extra devices
     • -ve
       • Break = whole network fails
       • Difficult to locate faults
       • Can't keep network running when adding new devices
   • Bus
     • All devices are connected to a backbone - shared cable
     • Signals passed in either direction
     • Cost-effective
     • Easy to install

8. Intranet

   • Internal private network

9. Extranet

   • External network - allows customer access