Patent ID: 8553869

Claim:
In a Media Gateway Control Function (MGCF), a Video Interworking Gateway (VIG), or both, of a multimedia communication system, a method for implementing a video Ring Back Tone (RBT) interworking, the method comprising: receiving a call request, which originated from a calling terminal of a user in a Circuit Switch (CS) domain, for a session with a called party in an Internet protocol Multimedia Subsystem (IMS) domain, which is a different network from the CS domain; based on the received call request from the CS domain, triggering a Multimedia Ring Back Tone (MRBT) service by sending a Session Initiation Protocol (SIP) invite message to an MRBT Application Server (AS) in the IMS domain; in response to the SIP invite message, receiving a reply message from the MRBT AS in the IMS domain, wherein the reply message includes information about if an MRBT needs to be played to the calling terminal in the CS domain; determining, according to the information in the reply message, that a video RBT in the IMS domain needs to be played at the calling terminal of the user in the CS domain; based on the determination, notifying a Mobile Switching Center (MSC) serving the user in the CS domain to put through the calling terminal; and thereafter, establishing a communication link with the calling terminal for playing the video RBT in the IMS domain at the calling terminal of the user in the CS domain.