The Design And Implementation Of Ims Multimedia Ring Back Tone Call Control System

Third Generation Partnership Project (3GPP) introduced the IMS (IP Multimedia Subsystem) as the3G era basic core network architecture to satisfy customers’needs of multimedia services in the future. With the rapid construction of3G networks in China, the2G value-added services are facing the challenges as well as opportunities to update themselves to adapt the3G networks. CRBT, as one of the most successful value-added services in the past10years in China, is still one of the important value-added services for the integration of a variety of media such as audio, video, animation, images, multimedia CRBT.This paper discussed IMS Multimedia Ring Back Tone (MRBT) service, designed and implemented a call control system for MRBT to play the multimedia files to the calling user during the ringing period.This system should be deployment in the IMS application layer and triggered by S-CSCF.The system is an instance of back-to-back user agent of SIP.It splited the session between the calling and called into two seesions-the calling to the system and the system to the called. The system maintained each sessions’status, and controled the media negotiation between the calling and the called.In this paper, the IMS network architecture, elements and protocols were introduced int the first part. Then it discussed the needs of MRBT service, inclueded the function of choosing the ring tone and the actions to accomplish the current session. The focus of this paper was the design and implementation of the system. In this part, it introduced the system’s static and dynamic models, the interaction between the system’s seperate parts, the system’s behavior under different session scenarios. In the last part, the paper introduced the testing and deploy situation of the system and summarized the writer’s work and harvest of the project.