Topologies

Topologies

1. Ring

   • Data flows in one direction, so goes through all computers to get to destination
   • Each device connected to 2 other devices
   • Devices receive packets in turn until gets to right one
   • Advantages: can transfer data quickly with lots of devices, travels in one direction so no collisions
   • Disadvantages: if one device fails whole network fails, data only flows in one direction

2. Bus

   • All devices connected to one cable, called the bus
   • Terminator at each end so data not sent back along
   • Advantages: easy to install, cheap as not much cable
   • Disadvantages: if main cable damaged whole network fails, slower as more devices as more data collisions, security risk as all computers see data

3. Star

   • Each device connected to hub or switch
   • Hub sends packets to all devices, switch sends it to destination device
   • Advantages: reliable as works with a failed cable, no data collisions so high speed
   • Disadvantages: expensive as uses most cable, extra hardware like switch and hub cost extra money, if hub or switch fails no connection so fails

4. Mesh

   • Connected by series of nodes connected wirelessly - use WiFi
   • Information hops from nodes using quickest safest route (called routing) to reach destination
   • Advantages: cheaper as not many wires so god for large networks, more nodes means faster, if one node breaks can use others, convenient outdoors as no Ethernet
   • Disadvantages: set-up and maintenance difficult and needed constantly, expensive to set-up but revenue gained over tiem, reconnection of nodes difficult