A metropolitan area network (MAN) is a computer network

Computer network

A computer network, often simply referred to as a network, is a collection of hardware components and computers interconnected by communication channels that allow sharing of resources and information....

 that usually spans a city or a large campus. A MAN usually interconnects a number of local area network

Local area network

A local area network is a computer network that interconnects computers in a limited area such as a home, school, computer laboratory, or office building...

s (LANs) using a high-capacity backbone technology, such as fiber-optical links, and provides up-link services to wide area network

Wide area network

A wide area network is a telecommunication network that covers a broad area . Business and government entities utilize WANs to relay data among employees, clients, buyers, and suppliers from various geographical locations...

s (or WAN) and the Internet

Internet

The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite to serve billions of users worldwide...

.

The IEEE 802-2002 standard describes a MAN as being:
Authors Kenneth C. Laudon and Jane P. Laudon (2001) of Management Information Systems: Managing the Digital Firm 10th ed. define a metropolitan area network as:
It can also be used in cable television.

Implementation

Some technologies used for this purpose are Asynchronous Transfer Mode

Asynchronous Transfer Mode

Asynchronous Transfer Mode is a standard switching technique designed to unify telecommunication and computer networks. It uses asynchronous time-division multiplexing, and it encodes data into small, fixed-sized cells. This differs from approaches such as the Internet Protocol or Ethernet that...

 (ATM), FDDI, and SMDS

SMDS

Switched Multi-megabit Data Service was a connectionless service used to connect LANs, MANs and WANs to exchange data, in early 1990s. In Europe, the service was known as Connectionless Broadband Data Service ....

. These technologies are in the process of being displaced by Ethernet

Ethernet

Ethernet is a family of computer networking technologies for local area networks commercially introduced in 1980. Standardized in IEEE 802.3, Ethernet has largely replaced competing wired LAN technologies....

-based connections (e.g., Metro Ethernet

Metro Ethernet

A Metro Ethernet is a computer network that covers a metropolitan area and that is based on the Ethernet standard. It is commonly used as a metropolitan access network to connect subscribers and businesses to a larger service network or the Internet...

) in most areas. MAN links between local area networks have been built without cables using either microwave

Microwave

Microwaves, a subset of radio waves, have wavelengths ranging from as long as one meter to as short as one millimeter, or equivalently, with frequencies between 300 MHz and 300 GHz. This broad definition includes both UHF and EHF , and various sources use different boundaries...

, radio

Radio

Radio is the transmission of signals through free space by modulation of electromagnetic waves with frequencies below those of visible light. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space...

, or infra-red laser

Free-space optical communication

Free-space optical communication is an optical communication technology that uses light propagating in free space to transmit data for telecommunications or computer networking."Free space" means air, outer space, vacuum, or something similar...

 links. Most companies rent or lease circuits from common carriers because laying long stretches of cable can be expensive.

DQDB, Distributed-queue dual-bus

Distributed-queue dual-bus

In telecommunication, a distributed-queue dual-bus network is a distributed multi-access network that supports integrated communications using a dual bus and distributed queuing, provides access to local or metropolitan area networks, and supports connectionless data transfer,...

, is the metropolitan area network standard for data communication. It is specified in the IEEE 802.6

IEEE 802.6

IEEE 802.6 is a standard governed by the ANSI for Metropolitan Area Networks . It is an improvement of an older standard which used the Fiber distributed data interface network structure. The FDDI-based standard failed due to its expensive implementation and lack of compatibility with current LAN...

 standard. Using DQDB, networks can be up to 20 miles (30 km) 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-West

MAE-West is a major Internet exchange point located on the west coast of the U.S. in San Jose, California and Los Angeles, California. Its name officially stands for "Metropolitan Area Exchange, West", although some note the similarity to the name of the actress Mae West...

, MAE-East

MAE-East

MAE-East is an Internet Exchange Point spread across the east coast of the United States, with locations in Vienna, Virginia; Reston, Virginia; Ashburn, Virginia; New York, New York; and Miami, Florida. It is the eastern branch of the MCI Internet Exchange. Its name officially stands for...

, and the Sohonet

Sohonet

Sohonet is a community-of-interest network for the television, film and media production community.Founded in 1995 by a group of Soho-based post-production companies, Sohonet links many of the British film studios to London's post-production community...

media network.