Design And Implementation Of SIP Multimedia Applications Oriented NGN

In this paper, two issues are studied. The first one is about the achievement of study on the VOIP based on SIP, and the second one is about the study on the SIP multimedia applications in the NGN open services platform, which is focused on the IM and presence services.In the future, network will be driven mainly by the services, and services rapid developing and deploying become more and more important. But nowadays most of these services are implemented with private protocols in Stovepipe Systems which are closed to each other, and they are not thoughtful of services extended. So it results that the services based on different solutions cannot communicate with each other, and also it is so difficult to extend new services. In addition, as the services increase, the service management turns difficult, and because resources cannot be shared, it leads a lot of resources waste. Therefore, it is very important to study how to make services extendible, how to make the application standardized, and how to make the service platform architecture flat. And that SIP and services platform based on NGN are appropriate solution.SIP is one of the most important protocols in multimedia session control. SIP is simple, open and extendible, and because SIP meets the requirements of the multimedia session application, SIP is now thought of much importance. This paper firstly studies the principle of SIP and the signaling mechanism, and compares SIP with other relevant protocols and applications. Then, the paper indicates the design and implementation of the H.323/SIP dual-module VOIP terminal, and analyses the value of the study from the point of view of Converged Communications. The paper mainly indicates the implementation of the SIP stack and the interfaces between the stack and other components. And then, the paper shows the test process and gives some proposals of improving the terminal.NGN (Next Generation network), adopting a lot of advanced technologies, and taking IP as central, is a Converged network that can supply many services, so is always the hotspot in the studies of communications. As the author has a good knowledge of SIP, the paper indicates how to create SIP services in the NGN service platform in the second part. The paper first introduces the NGN open services platform, and then studies the design and implement of presence service with SIP, which mainly give the design of SIP server capability and the SIP soft terminal. At last, a conclusion and a prospect are made.