LANs and WANs

LAN stands for Local Area Network. It is a network that covers a small geographical area, usually a single site such as one building, and it connects individual devices — computers, printers, tablets — within one organisation.

Because everything sits on one site, it is practical for the organisation to own and control the infrastructure itself: the cabling, switches and wireless access points are its own equipment, and its own staff decide who gets access. A village hall where the booking office, main hall and kitchen all link together is running a LAN.

Wide Area Networks

WAN stands for Wide Area Network. It covers a large geographical area and joins two or more networks or LANs at distant locations, so it links whole networks together rather than plugging individual devices straight into each other.

A WAN usually relies on third-party communication links, such as leased lines rented from a telecommunications provider, because running your own cable between distant towns is rarely practical or affordable. A chain of climbing centres with sites in Sheffield and Plymouth could link each site's LAN into one WAN. The internet is a global WAN that connects many separate networks.

A WAN is not only the internet — an organisation can run a private WAN between its own sites. Equally, Wi-Fi covering a single site is not a WAN, because wireless links can sit inside a LAN.

LAN or WAN?

So a LAN suits a single site, while a WAN is needed once sites are far apart — and the difference is about area, ownership and what is being connected, not simply the number of devices.