METHODS AND APPARATUSES FOR P-CSCF RESTORATION BASED ON UE CAPABILITIES

摘要

The present invention faces the issue of UE enabled to communicate with an IP Multimedia Subsystem following protocol versions older than Release 9, and provides for an alternative P-CSCF restoration procedure. In this alternative P-CSCF restoration procedure, the UE submits to the IMS network UE capability information indicating that the UE is enabled to receive a list with one or more further available P-CSCF entities and to re-register in the IMS network with one of them; at least one entity of the IMS network stores this UE capability information; upon detecting unavailability of the P-CSCF entity to handle a terminating request towards the UE, the UE capability information is provided towards and access network entity; the access network entity determines based on the received UE capability information that the UE is enabled to receive a list with one or more further available P-CSCF entities, obtains the list with further available P-CSCF entities and submits said list to the UE; and the UE reregisters to a further P-CSCF entity selected from the list.