Networks

Networks

1. Disadvantages

   • INCREASED RISK: problems such as viruses can affect every computer on the network
   • DIFFICULTY: expertise is needed to set up and maintain a network
   • COST: networks are expensive to set up

2. Types of network

   • WAN: wide area network
     • A network that spans a large geographical area or multiple organisations
     • Often consists of multiple LANs networked together
   • LAN: local area network
     • A network contained in a single geographical location or organisation

3. Advantages

   • SHARE LOGINS: so the same username and password can be used on every computer and network
   • SHARE RESOURCES: such as printers and internet connection
   • SHARE FILES: so the same files are available whichever computer you use

4. Topology

   • Bus Topology
     • Cheap to install (only one wire needed)
     • 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
   • Star Topology
     • 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
     • Failure of switch will take down the network
     • Expensive ( needs a lot of cabling and a central switch, which is expensive)
   • Ring Topology
     • Cheap to install (one cable per computer)
     • No collisions - only one computer is transmitting on each cable
     • High chance of catastrophic failure (if any cable breaks or any computer goes down, the entire network fails
     • Difficult to add new computers

5. IP Adresses

   • An IP Adress is a unique value assigned to every computer on a network, used to identify it
   • There are 4,228,250,625
     • An IP Address looks like this: 86.188.242.210. Each section can go from 000 - 255
   • An IP address is like a house address. It is needed to send messages like sending letters to houses

6. Internet

   • The internet is a mesh topology
   • Large files are sent in smaller packets and they are reassembled at the destination
   • Routes between nodes are chosen by seeing how much the cost adds up and they choose the smaller route