(With the deepening of the reform of the telecommunications system, the telecom industry has formed a competitive format of three full-service operators, and China Mobile is facing new challenges. Based on IP technology, providing multimedia information services through CM-IMS", that is, "wireless base station optical cable extension IP IMS" In the environment of full-service competition, data services such as broadband private lines will be greatly developed. At present, the network construction of each IP metropolitan area network is relatively weak and is in the preliminary construction stage. Each gradually started the construction or expansion of IP metropolitan area network to meet the needs of the whole business field. The construction of IP metropolitan area network has become an important subject of network construction in the metropolitan area at the present stage)