Networks

Networks

1. Advantages

   • Consistent User Experience
   • Shared files
   • Shared resources

2. LAN

   • Local Area Network: A network in a small area or single organisation

3. WAN

   • Wide Area Network: A network that spans a large area or multiple organisations

4. Disadvantages

   • Expensive – extra hardware and wiring needed
   • More room for error – if something goes wrong it can affect every computer
   • Difficult – it requires a technical expertise
   • Malware – viruses and other malicious software can spread through the network

5. Topologies

   • Bus
     • The network consists of a single cable that runs through the network All devices attach to this single cable
       • Disadvantages
         • 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
       • Advantages
         • Cheap to install (only one wire needed)
   • Ring
     • Computers are connected to each other in a ring Communication only goes in one direction
       • Advantages
         • Cheap to install (one cable per computer) No collisions - only one computer is transmitting on each cable
       • Disadvantages
         • High chance of catastrophic failure (if any cable breaks or any computer goes down, the entire network fails Difficult to add new computers
   • Star
     • All computers are connected to a central switch. The switch directs the traffic to the appropriate computer
       • Advantages
         • 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)
       • Disadvantages
         • Expensive (needs a lot of cabling, and a central switch, which is expensive) Failure of the switch will take down the network

6. IP Address

   • Internet Protocol Address
   • Each IP address on a network must be unique to prevent files from going to the wrong recipient.
   • An IP address is a unique value assigned to every computer on a network to identify it.
   • Unique addresses are signed to business and houses. These networks and houses run their own mini network inside with their own Ip address.
   • In all topologies, messages may pass through multiple devices on their way to their intended recipient
   • 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