Topologies

Topologies

1. Bus

   • Commonly used for LAN
   • Data is transferd in different directions to all connected devices
   • Advantages
     • Easy to install
     • Cheap
     • Requires little capable
     • easy to add more stations
   • Disadvantages
     • If the main capable fails, the whole network goes down
       • Cable failure is difficult to isolate
     • Network performance greatly decreased under heavy load
   • e.g. ethernet

2. Star

   • Each device is connected to a central host computer
   • Commonly used for wide area network in large companies
   • Advantages
     • Cable failure only effects one station
     • Simple to isolate faults
     • Consistent performance
     • No "collisions" of data as each station has its own cable server
     • Other stations cannot intercept messages (security)
     • Easy to add more stations
     • Different stations can transmit at different speeds
   • Disadvantages
     • Costly
     • requires many cables

3. ring

   • Computers are connected with no central controlling computer
   • All computers can connect/message each other but the connections always travels in one direction
   • Advantages
     • No dependence on a central computer
     • Simple messaging due to connections travelling in one direction
     • Very high transmission rates are possible
   • Disadvantages
     • If one node fails, the whole connection ring is broken