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Local area network

A local area network or LAN is a computer network covering a local area, such as an office or a home. This is different from personal area networks (PANs), metropolitan area networks (MANs) or wide area networks (WANs). LANs are typically faster than WANs.

The earliest popular LAN, ARCnet, was released in 1977 by Datapoint and was originally intended to allow multiple Datapoint 2200s to share disk storage. Like all early LANs, ARCnet was originally vendor-specific. Standardization efforts by the IEEE have resulted in the IEEE 802 series of standards. There are now two common wiring technologies for a LAN, Ethernet and Token Ring. Wireless technologies are starting to evolve and are convenient for mobile computer users.

When using Ethernet the computers are usually wired to a hub or to a switch. This constitutes the physical transport mechanism.

The Spanning tree protocol is often used to maintain a loop free network topology within a LAN, particularly with ethernet.

A number of network protocols may use the basic physical transport mechanism including TCP/IP. In this case DHCP is a convenient way to obtain an IP address rather than using fixed addressing. LANs can be interlinked by connections to form a Wide area network. A router is used to make the connection between LANs.

See also: CHAOSnet, DECnet, Wireless LAN.