In information technology, a network is a series of points or nodes interconnected by means of communication. Networks can interconnect with other networks and contain subnets.

A local area network (LAN) is a group of computers and associated devices that share a common communications line or wireless link. Typically, connected devices share the resources of a single processor or server within a small geographic area (for example, within an office building). Typically, the server has applications and data storage that is shared by multiple computer users. A local area network can serve as few as two or three users (for example, on a home network) or thousands of users (for example, on an FDDI network). See also: WAN and MAN

A wide area network (WAN) is a geographically dispersed telecommunications network. The term distinguishes a broader telecommunications structure from a local area network (LAN). A wide area network can be privately owned or leased, but the term generally connotes the inclusion of public (shared user) networks. An intermediate form of network in terms of geography is a metropolitan area network (MAN).

A metropolitan area network (MAN) is a network that interconnects users with computing resources in a geographic area or region larger than that covered by even a large local area network (LAN) but smaller than the area covered by a single one. wide area network (WAN). The term applies to the interconnection of networks in a city into a single larger network (which can then also offer an efficient connection to a wide area network). It is also used to refer to the interconnection of various local area networks by linking them with trunk lines. This latter use is also sometimes called a campus network.

A backbone is a larger transmission line that carries data collected from smaller lines that interconnect with it.

In a network, a node is a connection point, either a redistribution point or an end point for data transmissions. In general, a node has a programmed or designed capability to recognize and process or forward transmissions to other nodes.