A client (1) is coupled to a modem pool (2) and a server (5) by a communication link in a wide area network.

The computers can be located on a single computer network or on a plurality of interconnected computer networks such as two local area networks (LANs) coupled by a wide area network (WAN).

For the telephone, an inter-city or long-distance network is used (trunk network, toll network, long distance network).

Sometimes people mistakenly want to identify a Wide-Area Network (WAN) by the size of the network or by the devices that compose the network.