LAN is a computer network which spans a comparatively small region. Most LANs are limited to a single building or collection of buildings. Though, one LAN can be joined to other LANs over any distance through telephone lines and radio-waves. The system of LANs joined in this way is termed as wide-area network (abbreviated as WAN). Most of the LANs join workstations and personal computers. Each and every node in a LAN has its own CPU by which it executes programs; however it too is able to access data and devices anyplace on the LAN. This means that most users can share costly devices, like laser printers and also data. Users can too use the LAN to communicate with one other, by sending e-mail or engaging in the chat sessions.