Networks

Networks

1. Types of network

   • LAN
     • Network in a small area or single organisation.
   • WAN
     • Network that spans over a large area

2. disadvantages of networks

   • Cost
     • They are expensive to set up
   • Increased risk
     • Problems such as viruses can affect every computer on the network
   • Difficulty
     • Expertise is needed to set them up

3. Networks allow computers to

   • Share files
     • The same files are available whichever computer we use
   • Share resources
     • Such as printers and internet connection
   • Share logins
     • So the same username and password can be used on every computer on the network

4. Topologies

   • Bus topology
     • Advantages
       • cheap to install
     • Disadvantages
       • high chance of catastrophic failure
         • lots of collisions
           • slows down as more computers are added
   • Ring topology
     • Advantages
       • cheap to install
         • No collisions
     • Disadvantages
       • high chance of catastrophic failure
         • Difficult to add new computers
   • Star topology
     • Advantages
       • fast
         • easy to add new computers
           • low chance of catastrophic failure
     • Disadvantages
       • expensive
         • failure of the switch will take down the network
   • Mesh topology
     • Advantages
       • almost impossible to take down
         • easy to add new devices
           • adding new devices does not affect the network
     • Disadvantages
       • complex structure
         • difficult to set up

5. IP address

   • is a unique value used to identify computers on a network
   • messages on a network have an IP address attached this is how a computer knows whether or not to keep a message
   • the difficulty is that there is more devices on a network than there is IP address'
     • to solve this problem, houses and business' run their own mini network inside with a different IP address
   • an IP address is a 32 bit binary number
     • computers can convert this but it is hard for humans to use so we convert it binary to 8 decimal bits at a time