METHOD, SYSTEM AND DEVICE FOR REALIZING SERVICES IN THE INTERNET PROTOCOL MULTIMEDIA SUBSYSTEM NETWORK

摘要

A method and system for realizing services in the IP Multimedia Subsystem(IMS) network are disclosed in the present invention. The method includes the following steps: after the User Equipment(UE) in the roaming state registers successfully in the Enhanced Mobile Switch Center (E-MSC) of the local IMS network, the UE sends the session invite message to the Serving Call Session Control Function (S-CSCF) via the Proxy Call Session Control Function(P-CSCF); the S-CSCF sends the session invite message to the E-MSC according to the main call event triggering standard of the initial Filter Criteria(iFC); the E-MSC sends the initial address message to the Public Switched Telephone Network(PSTN) which the called user belongs to according to the called number in the session invite message; after receiving the address completion message returned by the PSTN, the E-MSC sends the ring message to the UE; and after receiving the answer message of the circuit domain sent by the PSTN, the E-MSC connects the IP media carrier between the E-MSC and the UE with the Circuit Switch(CS) media carrier between the E-MSC and the PSTN, and sends the answer message of the Session Initiation Protocol(SIP) to the UE via the S-CSCF and the P-CSCF in order to complete the establishment of the IMS session service. The present invention solves the roaming problem in the original locally deployed IMS network and reduces user reduplicate investment caused by the network evolution process.