Patent ID: 8588211

Claim:
A method for changing IP multimedia sub-system (IMS) centralized service (ICS) session media, comprising: receiving a media type change request comprising a new media type sent from one of a terminal equipment, a mobile switching center (MSC), and a party; releasing a first circuit-switched (CS) call leg based on an original media type between an IMS CS control function (ICCF) and the terminal equipment; establishing a second CS call leg based on the new media type between the ICCF and the terminal equipment; and updating the media type of a first call leg between the ICCF and the party into the new media type; wherein after releasing the first CS call leg, the method comprises: establishing, by the ICCF, a second call leg with a media resource function (MRF); binding, by the ICCF, the first call leg and the second call leg; receiving and transmitting, by the MRF, a real-time transport control protocol (RTCP) message with the party through the second call leg and the first call leg; and wherein the ICCF establishes a call connection between the terminal equipment and the party by binding the second CS call leg based on the new media type and the first call leg changed to the new media type.