What's a LAN?

VoIP technology has enabled telephony signals to run over dedicated networks using packet-switched protocols. One of the preferred methods of running VoIP in the corporate sector is to use dedicated lines. Instead of being primarily dependent on the PSTN for its telephone service requirements, companies using VoIP protocols can send and receive telephone calls over their private computer networks. 

A Local Area Network (LAN) is a network in which computers are relatively close together, such as within the same office or building. Note that the term LAN doesn't imply that the network is small. A LAN can, in fact, contain hundreds of computers. What makes a network a LAN is that all those computers are located within close proximity to each other. Usually a LAN is contained within a single building, but a LAN can extend to several buildings on a campus provided the buildings are close to each other.