The Design And Implementation Of Core Serving Control Function Entity In The IP Multimedia System

Along with widespread application of the IP technology, the IP tendency of network is even more obvious. At the same time, people expect a kind more convenient way of spanning fixed and mobile telecommunication network to obtain more multimedia services. Furthermore, facing the difficulties in the new service deployment and introduction which are brought by traditional network architecture, service operators expect a new network architecture which can quickly launch more new services to satisfy users.To provide multimedia services and implement the amalgamation of fixed and mobile telecommunication network much better, mobile communication third generation partnership project 3G standard in the Release5 edition to propose the IP multimedia system. The system uses session initiation protocol architecture which makes operation, call control, bearing apart, it has irrelevant ways of connecting. Putting forward IP multimedia system accords with the trend of mobile telecommunication development. At present the IP multimedia system has already became the core of future NGN which can provide multimedia services.In the IP multimedia system, there is an important serving control function entity called Serving–Call/Session Control Function (S-CSCF). The main function of S-CSCF is to provide session control and registering service. S-CSCF is located in the ownership network and is the central node of signaling plane and the core of system. The main research of this article is the design and implementation of S-CSCF. First of all, we analyzed the function,signal interface and supported processes the S-CSCF has to implement, then based on the whole design principles and the logical processes of message, we used the layered architecture and partitioned function models. After designed and implemented in detail, we realized serving-call/session control function entity at last.In the process of design and implementation, considering performance and concurrency, we used thread pool model in the process of service distribution. We designed the structure of stored context information, based the knowledge of disperse math, using evaluation arithmetic we implemented the interface of serving operation trigger which is called the interface of matching initial filter criteria trigger point. When we designed session context, we gave inter-context solution to solve the restriction of realism business income and system applicability. When we designed the logical processes of application layer, we gave the design of state diagram and the detail design of state, disposal and conversion rule. The S-CSCF can totally realize our anticipated functions, the whole IP multimedia system edition 1 has already completed, it can carry on the basic media telephone conversation, we believe the technology of IP multimedia system can certainly be more and more mature.