Metropolitan area networks, or MANs, are large computer networks usually spanning a city. They typically use wireless infrastructure or Optical fiber connections to link their sites.
IEEE definition
The IEEE 802-2001 standard describes a MAN as being:
| “ | A MAN is optimized for a larger geographical area than is 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 internetworking of local networks. Metropolitan area networks can span up to 50km, devices used are modem and wire/cable | ” |
Implementation
Some technologies used for this purpose are ATM, FDDI, and SMDS. These older technologies are in the process of being displaced by Ethernet-based MANs (e.g. Metro Ethernet) in most areas. MAN links between LANs have been built without cables using either microwave, radio, or infra-red laser links. DQDB, Distributed Queue Dual Bus, is the Metropolitan Area Network standard for data communication. It is specified in the IEEE 802.6 standard. Using DQDB, networks can be up to 30 miles long and operate at speeds of 34 to 155 Mbit/s. Several notable networks started as MANs, such as the Internet peering points MAE-West, MAE-East, and the Sohonet media network.
