IMT-2000 core network node systems

The IMT-2000 third-generation network system has been operating in the Japanese market since May 2001. In order to provide value added phone services including CAMEL services, a layered call control architecture has been developed. This architecture could achieve smooth core network migration from 2G to 3G. This system provides MSC/VLR, SGSN, and GGSN functionalities based on ATM technology.