Research And Design Of Media Routing Strategy On Sip-based Distributed Conference System

SIP-based conference system provides great convenience for people to make remote multiparty calls, therefore it becomes more and more popular. When laying conference system network, operators often deploy several conference servers and media servers, and make the same devices as backup. Because media servers need to handle signaling and media flow at the same time, they are heavily loaded nodes. So the routing policy used by conference servers to schedule media servers is very important. If it is inappropriate, not only make part of media servers under heavy load and fails, but also affect the overall performance of system, and cannot fully satisfy users’ session need. Therefore, researching and designing media routing policy for conference system has important theoretical and practical value, in terms of balancing media servers’ load, improving the stability and the overall performance of the system, improving the success rate of users’ session and so on.In order to design reasonable media routing strategy, the article mainly researched the load balancing problems of media server cluster. Firstly, analyzed the characteristics of media server’s hardware structure and proposed the number of media resource as its load evaluation index. On this basis, put forward dynamic feedback load balancing strategy based on resource state, and four types of load balancing algorithm:the surplus service capability algorithm, the improved surplus service capability algorithm, the improved round robin algorithm and the improved least connection algorithm. Then combined with the statistical laws of users’ session in actual life, built a load balancing model, and verified through computer simulation that the improved surplus service capability algorithm has optimal performance on increasing the session success rate, reducing the average response time and variance of bearing session times. The conclusion theoretically proved the dynamic feedback load balancing strategy based on resource state is of rationality and feasibility.To further improve the users’ session success rate, this paper also introduced disaster mechanism for media servers’ failure when designing media routing strategy. The mechanism’s core thought was that conference server detects media servers’ failure through registration update mechanism, then informs the failure information to the other conference servers through DDS synchronization mechanism. So when conference servers receive new session request, they will circumvent the fault node and select normal media servers to execute task.In addition, the article has designed conference server’s and media server’s software architecture and function modules’logic interaction process, provided the basis for implementation of media routing policy.The paper’s research results will supply method for designing large-scale SIP conference system of high reliability an high stability.