| 摘要 |
PROBLEM TO BE SOLVED: To provide a communication control device, a communication system, and a communication control method that can avoid wasteful use of resources of an IP multimedia subsystem (IMS) by keeping subscriber information in an old P-CSCF, even when a mobile terminal (UE) for some reason makes a request for re-registration with the IMS.SOLUTION: An S-CSCF 310: acquires a SIP REGISTER containing the address of a P-CSCF 320 that relays control information transmitted/received by a mobile terminal for the establishment of a voice call; performs registration of subscriber information associated with the mobile terminal on the basis of the acquired SIP REGISTER; retains the acquired P-CSCF 320 address in an address retention unit; and upon having acquired a registration request, if the address retention unit has the P-CSCF address, transmits on the basis of the P-CSCF address retained in the address retention unit, a Deregistration request requesting a P-CSCF that is assigned the P-CSCF address to delete the subscriber information. |
