Method, apparatus and system for processing registration backup data

A serving call session control function (S-CSCF) comprising:

• a processor;
• a receiver configured to cooperate with the processor to receive a registration request message that carries at least a user identity from a user equipment (UE) and multi-registration information;
• the processor configured to determine a lack of registration data corresponding to the user identity and determine, according to the multi-registration information, that the registration request message comprises an initial registration request relating to a multi-registration;
• and
• a transmitter configured to cooperate with the processor to send a first request message to a home subscriber server (HSS),
• wherein the first request message carries (a) the user identity, (b) multi-registration indication information and (c) server assignment type information, and
• wherein the multi-registration indication information indicates to the HSS that the first request message relates to a multi-registration associated with the user identity, and the server assignment type information that the first request message is a request for performing initial registration of the user identity.

An internet protocol multimedia subsystem (IMS) network, comprising a serving call session control function (S-CSCF) and a home subscriber server (HSS),

• wherein the S-CSCF is configured to:
• receive a registration request message that carries a user identity from a user equipment (UE) and multi-registration information;
• determine a lack of registration data corresponding to the user identity in the S-CSCF and determine, according to the multi-registration information, that the registration request message is an initial registration request relating to a multi-registration;
• and
• send a first request message to the HSS, wherein the first request message carries the user identity, server assignment type information for identifying that the first request message relates to an initial registration of a user, and multiple registration indication information indicating to the HSS that the first request message relates to the multi-registration associated with the user identity;
• and
• wherein the HSS is configured to send an answer message carrying registration backup data related to the user identity to the S-CSCF.