Method for implementing RBT interworking, media gateway control function device, and application server

A Media Gateway Control Function (MGCF) device, comprising:

• a receiver configured to receiving a call request that 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;
• a Multimedia Ring Back Tone (MRBT) triggering unit, configured to initiate an MRBT service based on the received call request from the calling terminal of the user in the CS domain by sending a Session Initiation Protocol (SIP) invite message to an MRBT Application Server (AS) in the IMS domain;
• a receiving unit, configured to receive a reply message sent by the MRBT AS in response to the SIP invite message, wherein the reply message includes information about if an MRBT needs to be played to the calling terminal of the user in the CS domain;
• a judging unit, configured to judge, according to the reply message received by the receiving unit, whether to play a video Ring Back Tone (RBT) in the IMS domain to the calling terminal of the user in the CS domain;
• a notifying unit, configured to notify a Mobile Switching Center (MSC) serving the calling terminal in the CS domain to put through the calling terminal after receiving a positive judgment result from the judging unit for playing the video RBT in the IMS domain at the calling terminal of the user in the CS domain;
• and
• a controlling unit, adapted to control setting up a communication link with the calling terminal in the CS domain for playing the video RBT from the IMS domain.

A computer program product comprising computer executable instructions stored on a non-transitory computer readable medium such that when the computer executable instructions are executed by a computer program processor of a multimedia communication system cause a Media Gateway Control Function (MGCF), a Video Interworking Gateway (VIG), or both, to implement a video Ring Back Tone (RBT) interworking that:

• receives 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, triggers 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, receives 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;
• determines, 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, notifies a Mobile Switching Center (MSC) serving the user in the CS domain to put through the calling terminal;
• and
• thereafter, establishes 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.