A voice gateway system based on P2P SIP VoIP

Introducing the P2P (Peer-to-Peer) technology into SIP (Session Initiation Protocol) networks can improve VoIP (Voice on Internet Protocol) system´s reliability and scalability, and reduce the operating costs. In order to provide better and more comprehensive services in VoIP system, it is necessary to communicate with the traditional telecommunications networks, including PSTN (Public Switched Telephone Network), by a voice gateway. The voice gateway system for P2P-based SIP VoIP builds the connection, and transforms signaling and media, between IP service network and PSTN. SIP-in-P2P is implemented in voice gateway system, using DHT (Distributed Hash Table) scheme to connect VGW (Voice Gateway) nodes in the P2P SIP network. Based on the GWMN (Gateway Management Node) protocol, the system can manage VGW nodes in the management domain, and designed the discovery strategies and load balancing strategies to improve the performance. Results indicate that the voice gateway system performs with good reliability, scalability, interoperability and feasibility.