Method and apparatus for processing registration backup data

A network device, comprising:

• a first receiving module, configured to receive a registration request message that carries an Internet Protocol Multimedia Subsystem (IMS) Private User Identity (IMPI) and IMS Public User Identity (IMPU) pair during a registration of a user;
• and
• a processing module, configured to:
• in response to receiving the registration request message, determine:
• a) a lack of registration data corresponding to the IMPI and IMPU pair stored by the network device;
• and b) that the registration request message comprises a reg-id parameter which indicates that the registration relates to a multi-registration associated with the IMPI and IMPU pair;
• send a Server Assignment Request (SAR) message to a Home Subscriber Server (HSS), wherein the SAR message carries the IMPI and IMPU pair, a parameter for identifying that the registration relates to an initial registration, and a multiple registration indication which indicates that the registration relates to the multi-registration associated with the IMPI and IMPU pair;
• and
• receive a Server Assignment Answer (SAA) message carrying registration backup data corresponding to the IMPI and IMPU pair from the HSS.

A network device, comprising:

• a receiving module, configured to receive a Server Assignment Request (SAR) message sent by a Serving Call Session Control Function (S-CSCF) in an Internet Protocol Multimedia Subsystem (IMS) network during a registration of a user, wherein the SAR message carries an IMS Private User Identity (IMPI) and IMS Public User Identity (IMPU) pair, a parameter for identifying that the registration relates to an initial registration, and a multiple registration indication which indicates that the registration relates to a multi-registration associated with the IMPI and IMPU pair;
• and
• a processing module, configured to:
• determine:
• a) that the multiple registration indication is included in the SAR message;
• and b) that the IMPI and IMPU pair is stored as registered in the network device and registration backup data related to the IMPI and IMPU pair is stored in the network device;
• and
• send a Server Assignment Answer (SAA) message carrying the registration backup data related to the IMPI and IMPU pair to the S-CSCF.