A large computer network, which covers the urban area or city. This type of network uses most often optical-fiber connections for communication between its constituent scattered LANs.

Metropolitan networks are built to provide inhabitants access to the Internet, but also by large government organisations, educational or private, which need fast and safe data exchange between points in locality with the participation of no third party. The technologies used in building such networks include ATM, FDDI, SMDS, and recently Gigabit Ethernet. Where it is impossible to use the optical-fiber connections, the wireless radio, infrared or laser connections are commonly used.