LAN (Local Area Network) is a computer network within a small area, such as a home, school, computer laboratory, office building or group of buildings. Most LANs connect workstations and personal computers that share a common communications line or wireless link. A local area network may serve as few as two or three users (for example, in a home network) or as many as thousands of users (for example, in an FDDI network. A system of LANs connected each other over any distance via telephone lines and radio waves is called a wide area network(WAN)).
There are many different types of LANs. Among them the Ethernets have been the most common for PCs. Some types of LANs:
Simple LANs generally consist of one or more switches and the switch would always connect to a router, cable modem, or ADSL modem for Internet access. Complex LANs are characterized by their use of redundant links with switches using the spanning tree protocol to prevent loops so that they can manage different traffic types via quality of service, and to segregate traffic with VLANs. A local area network can also include a variety of network devices, such as switches, firewalls, routers, load balancers, and sensors etc.
LANs can maintain connections with other LANs via leased lines, leased services, or the Internet using virtual private network technologies. Depending on how the connections are established and secured in a LAN, and the distance involved, a LAN may also be classified as a metropolitan area network (MAN) or a wide area network (WAN).