A metropolitan area network (MAN) is a computer network larger than a local area network, covering an area of a few city blocks to the area of an entire city, possibly also including the surrounding areas.
A MAN is optimized for a larger geographical area than a LAN, ranging from several blocks of buildings to entire cities. MANs can also depend on communications channels of moderate-to-high data rates. A MAN might be owned and operated by a single organization, but it usually will be used by many individuals and organizations. MANs might also be owned and operated as public utilities. They will often provide means for inter networking of local networks.
Kenneth C. Laudan and Jane P. Laudan define a metropolitan area network as:
A Metropolitan Area Network (MAN) is a large computer network that spans a metropolitan area or campus. Its geographic scope falls between a WAN and LAN. MANs provide Internet connectivity for LANs in a metropolitan region, and connect them to wider area networks like the Internet.
Also known as a Municipal Area Network, networking technologies used in municipal networks include Asynchronous Transfer Mode (ATM), FDDI, and SMDS. However, these technologies are increasingly being displaced by Ethernet-based connections (e.g., Metro Ethernet). MAN links between local area networks have been built with wireless links using either microwave, radio, or infra-red laser transmission. Most companies rent or lease circuits from common carriers because laying long stretches of cable is expensive.
Distributed-queue dual-bus (DQDB) refers to the metropolitan area network standard for data communication specified in the IEEE 802.6 standard. With DQDB, networks can extend up to 20 miles (30 km) long and operate at speeds of 34–155 Mbit/s.