Metropolitan area network is basically a large local area network, which usually uses LAN-like technology. One of the main reasons for listing MAN alone is that there is already a standard: DQDB(Distributed Queue Dual Bus), which is IEEE802.6. DQDB is composed of two buses, and all computers are connected to these two buses.

The so-called broadband metropolitan area network is a multimedia communication network with high bandwidth, multi-function and multi-service access, which is based on IP and ATM telecommunications technology and takes optical fiber as transmission medium and integrates data, voice and video services.

It can meet the growing demand of government agencies, financial insurance, schools, companies and enterprises for high-speed and high-quality data communication services, especially the demand of fast-growing Internet users for broadband high-speed Internet access.