Realization Of Conference Server Based On SIP

With the popularity of computer, as well as the wide-spreading establishment of high-speed networking and excellent-performance computer technologies, the multimedia conference is attracting more and more attention of people. H.323 and SIP are the main signaling protocols which control multi-media sessions in a multimedia conference system over the current packet network. Multimedia conference based on H.323 is quite mature, but it costs much because it is complicated in the implementation and extending. However, SIP appears simple, flexible and open which make it easy to be extended for special use. SIP is emphasized and supported as soon as it is released. The research on SIP-based multimedia conference system becomes popular.This thesis firstly describes Session Initiation Protocol (SIP), and the network architecture of SIP systems, and then analyses the SIP message structure, and compares the open source SIP stack, Secondly introduces protocol and technology related, including Session Description Protocol (SDP), Real-time Transport Protocol (RTP) and the CODEC technologies.Comparing with the conference system model of H.323, the SIP conference model is preferred. Based on the analyzing of signaling and the multimedia topology of SIP conference model, the tightly coupled conference that supports the Dial-In, Dial-Out and special model conference is introduced. Cascade mixers and cascade focus are used to support larger conferences. In addition, the signaling flow of the whole system is introduced, by which the communication process is shown clearly.The realization of our multimedia conference server is introduced in the last part of this thesis. After analyzing the logical framework, we divide it into four modules: Signaling processing module, multimedia processing module, database module and WEB module, At last introduce the design and realization method of each module.