Sip-based Multimedia Conferencing Systems Research And Development

The multi-media conference has the effect of face to face communication and then save time and expense, raises the conference efficiency,overcomes the disadvantage of the traditional correspondence tool, so it has been used widely. At present, the multi-media conference system including H.320 system based on switch circuit network and H.323 system based on packet based network has the disadvantage of low using rate of resource, complex of designing, difficult to extending. With the development of next generation network (NGN),softswitch,sip, It is easy to design and implement a multi-media conference system that has the high using rate of resource ,is easy to extend. On the basis of studying the traditional multi-media conference system, it's key technologies, softswitch, NGN network frame and the SIP protocol, this paper proposes a project of NGN multimedia conference based on SIP protocol, analyze the function, the meeting process of the each model, and realization and the test of the key part multi-controller in multi-conference. This system has the strongpoint of high using rate of resource, high speed of access, easiness of implement. Because SIP is based on text protocol, it is easy to debug the devices coming from different providers. Because softswitch has the ability to match the different protocols, terminals with the different protocols can access this system. The contents of the dissertation are distributed as follows: â—†Introduction of multi-media conference system's theory and it's development. Multi-media conference system is constituted of conference terminal, MCU, network and control software. MCU is the key device. It provides the function of mixing and switching the video, audio, and data. â—†Introduction of theory and development of next generation network. NGN With softswitch for the core is divided into four layers: brim access, core transmission, control, and service application. NGN has the advantage of opening, providing the business conveniently, in which the parts pass the standard protocol connecting each other, the business and calling control that separate etc. â—†Introduction of constitutes and calling process of sip and Comparison with H.323. SIP includes user agent and network server. Its message coding is based on text. â—†Implement of a multi-media conference system based on SIP protocol. This...