Research Of SIP-Based Centralized Multimedia Conference System

Session Initiation Protocol defined by IETF is one of the framework agreements of multimedia communication system. The agreement is a text-based control protocol in application layer, used to establish, modify and terminate multimedia sessions. With its readability, flexibility, good expandability and robustness SIP is getting more and more attention in Internet application, and is considered the most promising signaling protocol in multimedia business.Research work is based on standards or drafts of SIP meeting framework defined by IETF and a certain communications company development projects, research of several models of multimedia conference system based on SIP. Then for the centralized conference pattern, the system frame structure is further analysis and design. Propose a media control protocol (not SIP extension) used to communication between servers. Analyzes the characteristics of this agreement, and realizes its function on the media server.The main contents are summarize as follows:Analyze several patterns of multimedia conference, and describe the physical framework, communication norm, each main module function and framework structure of multimedia conference system based on SIP. Expound the whole structure of multimedia conference system.Give emphasis to design and realize the processing of control protocol on the media server in this paper. According to media server internal modules, it is divided into main task module, control channel, handing media control message module, analyze the software design process of these modules in detail, and realize the function of these modules via programming. Then expound the realization process of these modules. Complete the media control signaling dispose in media server, as well as the creation process of meeting.Based on Vxworks embedded operating system development platform, complete coding design work of media server. Then through building a small LAN to test the function of media server. Verify the feasibility of this scheme, the correctness of handing media control protocol in media server. For the multimedia processing function of this system, Later can be expand according to need, so it has flexible expansion function.