SUPPLY QUALITY SERVICE VOIP THROUGH CALL SIGNALING OVERLOAD CONTROL

SIP (session initiation protocol (is an application layer protocol to create, maintain and ending the multimedia sessions. These protocols have no suitable mechanism for encountering with the overload, so when a server is overloaded, it`s effectiveness is reduced and eventually server’s real throughput reaches zero. To control the overload, various methods have been proposed, but there are some basic challenges presented in presented methods that lead to poor performance while there is an overloaded server in the network. The current study focusing on server – server’s overload, a distributed overload control method, based on dynamic window and implicit feedback is proposed to control overload. In order to extend the originally proposed algorithm which uses the violation of the calling delay from a specific threshold as an incentive for reducing the sending load to downstream proxy, adaptive methods are proposed. The performance of the proposed algorithms has been evaluated.