ARCHIVED: What is a LAN (local area network)?

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Local area networks (LANs) are computer networks ranging in size from
a few computers in a single office to hundreds or even thousands of
devices spread across several buildings. They function to link
computers together and provide shared access to printers, file
servers, and other services. LANs in turn may be plugged into larger
networks, such as larger LANs or wide area networks (WANs), connecting
many computers within an organization to each other and/or to the
Internet.

Because the technologies used to build LANs are extremely diverse, it
is impossible to describe them except in the most general way.
Universal components consist of the physical media that connect
devices, interfaces on the individual devices that connect to the
media, protocols that transmit data across the network, and software
that negotiates, interprets, and administers the network and its
services. Many LANs also include signal repeaters and bridges or
routers, especially if they are large or connect to other networks.

The level of management required to run a LAN depends on the type,
configuration, and number of devices involved, but in some cases it
can be considerable.