A group of two or more computer systems linked together for the purpose of communications or application distribution. There are many types of computer networks, including local area networks (LANs)—made up of computers that are geographically close, and wide area networks (WANs)—where computers are farther apart and are connected by telephone lines or radio waves (see definitions below). Most State highway agencies use both LANs and WANs to link computers in their headquarters, divisions or districts, and remote area offices. Computers on a network are sometimes called “nodes.” Computers and devices that allocate resources for a network are called “servers.”