Patent ID: 8811288

Claim:
A method for enabling delivery of a message in a communication system comprising an IP Multimedia Subsystem (IMS) domain and a circuit switched domain, the method comprising: receiving a registration message in the IMS domain from a user equipment operated by a user, the message comprising an Equipment Identifier valid for the user equipment and an IP Multimedia Private Identity (IMPI) valid for said user, extracting the Equipment Identifier and the IMPI from the received message; initiating one of a creation and an update of a mapping of said Equipment Identifier to said IMPI and a Correlation Mobile Subscriber International ISDN Number (C-MSISDN); and initiating a use of the mapping for translating between said Equipment Identifier, the IMPI and the C-MSISDN when messages relating to the user are communicated between the IMS and circuit switched domains in the communication system.