1. Notion of network

1.1 Channel and network

In communications, there are two basic types of link: channels and networks.

A channel is a direct communication link between a source and a destination, i.e. a point-to-point connection. In video, for example, an RS 422 link between an editing table and a VTR is a channel. The RS 422 "port" is directly connected at a given moment to a well-defined VTR (even if it is bay-switchable). The direct parallel link between a computer and its printer is also a channel.

A network, on the other hand, is an architecture...