A local area network (LAN) supplies networking capability to a group of computers in close proximity to each other such as in an office building, a school, or a home.

A LAN is composed of inter-connected workstations and personal computers which are each capable of accessing and sharing data and devices, such as printers, scanners and data storage devices, games or other applications anywhere on the LAN. LANs are characterized by higher communication and data transfer rates and the lack of any need for leased communication lines. Users can use the LAN to communicate with each other, by sending e-mail or engaging in chat sessions.

Most local area networks use Wi-Fi or Ethernet for connectivity between devices.

The following characteristics differentiate one LAN from another:

                -topology :  The geometric arrangement of devices on the network. For example, devices can be arranged in a ring or in a straight line.

                -protocols : The rules and encoding specifications for sending data. The protocols also determine whether the network uses a                                                     peer-to-peer or client/server architecture.      

                - media :      Devices can be connected by twisted-pair wire, coaxial cables, or fiber optic cables. Some networks do without                                                        connecting media altogether, communicating instead via radio waves.

Power over Ethernet ( PoE ) is a technology for wired Ethernet LANs (local area networks) that allows the electrical current necessary for the operation of each device to be carried by the data cables rather than by power cords. Doing so minimizes the number of wires that must be strung in order to install the network. The result is lower cost, less downtime, easier maintenance, and greater installation flexibility than with traditional wiring. Unlike standards such as Universal Serial Bus which also power devices over the data cables, PoE allows long cable lengths. Power may be carried on the same conductors as the data, or it may be carried on dedicated conductors in the same cable.