networks

networks

1. bus

   • it uses one single network
     • High chance of catastrophic failure (a break in the central cable takes out the entire network)
       • High chance of collisions (multiple communications on the same cable that corrupt each other, slowing down the network)
         • More computers mean more collisions, so the network gets slower as it gets bigger
           • Cheap to install (only one wire needed)

2. star

   • All computers are connected to a central switch.
     • Expensive (needs a lot of cabling, and a central switch, which is expensive)
       • Failure of the switch will take down the network
         • Fast (low chance of collisions)
           • Easy to add new computers
     • Low chance of catastrophic failure (a broken cable only takes out one computer, the rest of the network is fine)

3. ip address

   • must be unique
     • if it is not unique people can download the thing you have sent
   • We get round this by assigning an “external” IP address to each house or business, then “internal” IP addresses to the computers in that house or business
   • The Internet is a huge network with more devices than it’s possible to assign a unique address to Unique addresses are assigned to businesses and houses
   • An IP Address is a unique value assigned to every computer on a network, used to identify it

4. internet

   • giant mesh of computers
     • It is impossible to break the Internet, since another route can always be found
       • All data on the Internet is split up into small chunks called packets Each packet is numbered and sent independently