IP MULTIMEDIA SUB-SYSTEM, PROXY SESSION CONTROL DEVICE, AND COMMUNICATION CONTROL METHOD

摘要

PROBLEM TO BE SOLVED: To provide an IP multimedia sub-system, a proxy session control device, and a communication control method that are able to perform re-registration of a user device corresponding to a working state of the proxy session control device (P-CSCF) regardless of a release the user device is based on.SOLUTION: A P-CSCF 310 comprises: an incoming processing unit 311 for receiving a SIP INVITE including an identifier of UE relayed from an S-CSCF in response to reception of incoming to the UE; a restoration execution unit 313 for executing restoration of a subscriber profile associated with the UE on the basis of receiving the SIP INVITE; and an address holding unit 315 for holding an address of a PCRF included in a response received from a DRA involved in execution of restoration. The restoration execution unit 313 re-establishes a session between the UE and the PCRF on the basis of the held address of the PCRF, and makes the UE perform re-registration to an IP multimedia sub-system.