Patent AT-E400962-T1: [Translated] EXCHANGE AND USE OF GLOBALLY UNIQUE DEVICE IDENTIFIERS FOR INTEGRATION OF CIRCUIT SWITCHING AND PACKET SWITCHING

A system and method of exchanging GRUUs (Globally Routed User Agent URI (Uniform Resource Identifier)) between a first telephony-enabled device and a second telephony enabled device using a circuit-switched message is provided. Once exchanged, the telephony enabled devices can exchange SIP (session initiated protocol) communications routed by the GRUUs. Any one of the telephony-enabled devices can add a media component to the SIP communications. Also a system and method of generating GRUUs is provided. According to another aspect, a system and method of handing off communications to a packet switched network from a circuit switched network is provided.