Networks

Networks

1. Advantages

   • Hardware can be shared
   • Software can be shared
   • Data can be shared
   • Networked computers can communicate
   • Network computers can be centrally controlled by a network manager
   • Files stored on a server allow easier backup schedules

2. Disadvantages

   • The cost of cabling and setting up is high
   • Viruses spread very quickly
   • Hackers may gain unauthorised access
   • Networks can fail to work properly

3. Types of server

   • File server network
     • A computer on a network that holds files that can be used by other computers on the same network
   • A client server network
     • One computer acting as a file server
   • Peer to peer network
     • All computers are of equal importance

4. Topologies

   • Bus network
     • Advantages
       • Cheap network to set up
       • If a computer fails the network continues to work
     • Disadvantages
       • Speed of data is slow
       • If network cable breaks, none of the computers can access the network
   • Star network
     • Advantages
       • If a cable breaks, all the other computers can still access the server
       • Direct, fast access to file server
     • Disadvantages
       • Expensive due to cabling needs
       • If the file server fails, all the other computers are affected
   • Ring network
     • Advantages
       • Cheap to set up
       • Data speed is continuous
     • Disadvantages
       • If any computers or network cable breaks it can affect the whole network

5. Nets

   • Intranet
     • A network providing similar services to the internet but only available to one company
   • Extranet
     • Part of the intranet that can be accesses by authorised members of the public
   • World Wide Web
     • The collection of multimedia resources or info available on the internet

6. Security

   • Protecting a network from unauthorised access
     • Usernames and passwords
     • Firewalls
     • Access rights
   • Protecting a network from viruses
     • Firewall
     • Anti virus software

7. Data transmission

   • Switch
     • A device that filters data packets and forwards them between segments of the network
   • Network interface cards
     • Computer hardware that allows devices to connect to a wired network
   • Gateway
     • A system allowing a LAN to connect to a WAN like the internet
   • Router
     • Determine the best path for forwarding the packets, by communicating with other routers
   • Bridge
     • Connects a LAN to another LAN