Softswitch Technology Call Control Model

With the development of telecom technology and the gradually opening of telecom market, the most important development trend is separation between service and network. Network providers supply dependable and efficient basic platform and service providers supply much of applications, which drive telecom industry to prosper and progress. Because application system directly faces the need of different users, it will be much more complicated than supporting system. So service providers of the next generation network have to depend on abundant services and applications to survive and develop. The relative telecom sets must be strongly capable of providing service to build NGN comprised of voice service, data service and video service.Thus that leads soft switch technology to develop.NGN is a kind of whole network solution, belonging to the services driving network, which uses open network structure. In this structure, service and call control, as well as call and carrying, can be separated. The goal of the separation is to make services quite independent of network and to support services flexibly and effectively. The soft switch technology separates the call control function from the media gateway, and realizes the basic call control function through the software on the server. The soft switch technology develops rapidly with the characteristics of strong elasticity, standard interface, opening service, and so on. Softswitch adopts transverse combination, open interface and generalized protocols to form the open, distributed and multi-manufacturer applied system architecture, so it has become one of the core technologies of Next Generation Network (NGN).This thesis begins with the definition and characteristic of the NGN, describes the excellent characteristics of NGN, and makes a detailed instruction about the significant parts in the next generation network. The paper introduces the functional architecture of softswitch service system, and analyzes the representative ways of service provide, and then research the Basic Call Process Module and the Finite State Model.