A Local Area Network, or LAN as it is more widely called, is a group of computers in a localized area. The term localized area could mean a small room, twenty feet by ten feet, or it could mean a factory spanning several acres. Another definition, widely accepted, states that a LAN is a computer network that is confined to a building or a cluster of buildings. A LAN is a network that is typically personal to an organization and is installed for the exclusive use of a particular office or factory of a given organization. It is not often that you will come across two or more organizations in an office complex sharing a LAN.