A Voice Gateway System For P2p-based Sip VoIP

SIP (Session Initiation Protocol) is widely used in VoIP (Voice on Internet Protocol) systems. But, the traditional SIP network is over dependent on the central control SIP servers, leading to poor system reliability, high maintenance costs, and introducing the P2P (Peer-to-Peer) technology into SIP networks can avoid these problems. In order to provide better and more comprehensive services, we need to communicate with PSTN (Public Switched Telephone Network), which made the voice gateway system for P2P SIP VoIP.The voice gateway system for P2P SIP VoIP connects the IP network to PSTN. It transforms signaling and media between SIP and PSTN. Voice gateway system merges P2P technology with SIP, provides a manner of sip-using-p2p and realizes it. Realizing the algorithm of large-scale access and maintenance, the GWMN (GateWay Management Node) assigns the management of voice gateway resources for VGW (Voice GateWay node), and VGW can join or leave the network, achieve self-maintenance and updates dynamically. VGW realized the algorithm of publishing and search for voice gateway resources; VGW publishes the voice gateway resources, and assumes the search for resources. The system researches using GWMN to manage VGW in the management domain, according to the geographical difference of VGW, when it join in the P2P SIP network it accesses to the management domain. Realizing the discovery strategies and load balancing strategies which based on GWMN`s management domain for voice gateway system, assigning sessions to VGW by the current load capacity of them, and through ther GWMN to realize the voice gateway resources discovery mechanism.Through the actual deployment of the system, we verify the functions of voice gateway system. In the simulation system, we test the call capacity and call delay of the system; from the test results, we know the call establishing delay of the system meet the recommendations of the International Telecommunication Union standard for Internet telephony. Through the performance test, we can verify that the mass deployment of voice gateway system is feasibility and the system will be robustness.