Wide Area Network (WAN) is a computer network covering vast territories (i.e. any network whose communications connect entire metropolitan areas, regions or even countries and contain dozens, hundreds or even millions of computers). For comparison, Personal area network, Local area network (LAN), Campus area network, or Metropolitan area network (MAN) usually do not go beyond a room, building, or a specific region of a metropolis (i.e. city).
Global networks unite computers located hundreds or even thousands of kilometers away from each other. Often existing, not very high quality, communication lines are used. Typically, a WAN has a lower data transfer rate than a LAN, mainly due to the greater distance of computers from each other, but theoretically, a WAN has the ability to provide the same speed as a LAN, MAN or CAN by using technologies such as fiber optics.
A WAN is used to link LANs and other types of networks together, so users and computers from one location can connect to users and computers from another. Many WANs are built for one particular organization and are private. Others are built by Internet service providers to provide connectivity between an organization’s local network and the Internet. WANs are often built using leased lines. At each end of a leased line, a router connects to a local network on one end and a router within another local network on the other. Leased lines can be very expensive. Instead of using leased lines, wide area networks can also be built using cheaper methods: circuit switching or packet switching. Network protocols including TCP/IP deliver transport and resolve functions. Protocols including packet over SONET/SDH, MPLS, ATM and Frame Relay are often used by service providers to provide links that are used in wide area networks. X.25 was an important early WAN protocol, and is often regarded as the “grandfather” of Frame Relay, as many of the core protocols and features of X.25 are still in use today[when?] (with upgrades) over Frame Relay.
Academic research in WAN can be broken down into three areas: Mathematical models, network emulation and network simulation.
Performance can sometimes be improved through WAFS or WAN optimization.
Wide Area Network (WAN) is a set of computers-nodes remote from each other, whose joint interaction is provided by a communication network of data transmission and special programs of the network operating system. WAN is based on powerful multi-user computing systems (Host – nodes) and specialized computers that perform the functions of communication nodes.