A computer network is a collection of computers linked together so that they can communicate with each other.

A computer that is not connected to a network is called a stand-alone computer.

There are two different sorts of computer network:

• ‘Local Area Network’ or ‘LAN’ - the computers are all in the same building or in different buildings on one site permanently connected to each other with special cables.
• ‘Wide Area Network’ or ‘WAN’ - the computers are spread over a large geographical area not permanently connected to each other communicate using telephone lines, radio transmitters or satellite links.