metropolitan area network (MAN) is a computer network that interconnects users with computer resources in a geographic region of the size of a metropolitan area. The term MAN is applied to the interconnection of local area networks (LANs) in a city into a single larger network which may then also offer efficient connection to a wide area network. The term is also used to describe the interconnection of several local area networks in a metropolitan area through the use of point-to-point connections between them 

Metro ethernet

The metro Ethernet rings that did not route IP traffic, instead used one of the various proprietary spanning tree protocol implementations, so that each MAN ring had a root bridge. Because layer 2 switching can not operate if there is a loop in the network, the protocols to support L2 MAN rings all need to block redundant links and thus block part of the ring.[4]:41 Capsuling protocols, such as Multiprotocol Label Switching (MPLS), were also deployed to address the drawbacks of operating L2 metro Ethernet rings.

Uses of MAN

Since a metropolitan area network only refers to relative size, it may also be used to describe a public or private network that attempts to provide connectivity that covers an entire metropolitan area. In this sense, a MAN can be closely related to smart city concepts in several different ways:

  • A MAN may be a large number of privately owned or telecommunication provider interconnects between organizations.
  • A MAN may be a public or free Wi-Fi system provided to residents of a city.
  • A MAN may be a network used by a municipality or company to interconnect its public works systems and internet of things (IoT) devices

It is quite different from WAN Wide area network.