Design And Implmentation Of Click To Dial System Based On SIP Application Server

With the rapid development of Internet, traditional telecom operators are eager to broaden business filed to Internet to look for new growth points, and Internet users also hope to be able to use convenient, reliable telecom services. Therefore, it is an urgent need to make services from telecom network and Internet interact and integrate, and CTD (Click to Dial) is a typical service form.CTD is one of basic service characteristics of NGN (Next Generation Network). Based on this characteristic, you can make full use of the capabilities of Internet for aggregating information/users on the web and friendly user operating interfaces to provide convenient information/application access means for Internet users with a combination of extensive use of traditional telephones and its end-to-end interactive capacity.CTD is implemented in the form of IN(Intelligent Network) service in the first. As the network evolves into Softswitch environment, CTD can be provided in Softswitch equipments. However, this goes against the principle of separation of services and call controls. As the main part of service supporting environment, AS(Application Server) provides the core service logic execution environment for a variety of value-added services, and makes uses of network resources through communicating with core network equipments using open and standard protocols which makes the separation of services and call controls to be realized. Therefore, it is a ideal way to provide the CTD service in AS, and because of its simplicity, openness, flexibility and expansibility, SIP(Session Initiation Protocol) will be a ideal communication protocol used between AS and other core network equipments.The dissertation illustrates a complete CTD system from several aspects: service model, signaling analysis, design and implementation, security issues, and so on. Main content includes:(1). The prefaceFirst the dissertation introduces the concept of CTD service as well as its origin, background and history, then analyse the domestic and international researches about this topic and trends briefly.(2). The introduction to application server and SIPThe dissertation introduces basic concepts of next generation network(NGN), especially the network architecture to switchsoft and IP multimedia subsystem as the core. In this architecture, application server, as the main services provider, provides supports for executing environment, development and operating management. Finally, the dissertation introduces NGN control protocol - SIP(Session Initiation Protocol)including the basic concepts, architecture and protocol structure.(3). The design and implementation of CTD systemThe dissertation puts forward a CTD service model in the first, and then analyses the core technology used to implement this basic model: 3PCC(The 3rd Party Call Control) and gives a number of relatively complex application cases. Then, the dissertation describes the design and implementation of service gateway and service platform these two core subsystems focusing on the basic architecture, interface design, core modules, and several important functions.(4). Security issuesThe dissertation explores security issues in web service interface, SIP signaling, service use these aspects for CTD application.(5). Performance testsIn the end, we do some performance tests based on a CTD basic call flow for the system, and the test results proves that it can meet the design objects, but there are also areas of improvement as the future work.