My paper abstract：

Peer to Peer (P2P) and Voice over IP (VoIP) are currently two highlights in the field of international internet application technology. P2PVoIP is a combined P2P and VoIP system and recently is an important subject of internet technology. P2PVoIP have high performance in VoIP by using P2P high robustness and scalability. Considering presently existent problems of VoIP, we analyse current P2P system’s advantages and use basic principle of P2P. This paper presents a general design framework for hybrid structured P2P IP software phone and we implemented a prototype. In paper the disadvantages of current VoIP system are analysed, and current P2P system’s workflow and principle are compared, it analyse the current P2PVoIP system in detail. From the above mentioned considerations the hybrid structured peer to peer VoIP prototype is presented. The achievements of this work are summarized as follows:
（1）The general design framework for hybrid structured peer to peer IP software phone system. There is no centralized server and network self-organizes itself. It change old VoIP system workflow and it have scalability, robustness, denial of service (Dos) attack and fault tolerance. System increases voice quality of local area network (LAN).
（2）We implemted a prototype of hybrid structured P2PVoIP software. As the DHT was used with hybrid structured P2P in the paper. So the system does not depend on commercial servers and company’s maintenance. It will save a lot of money. It hasn’t single point of failure. As it use Kadmelia DHT algorithm that can assure decrease latency for search node. The system can connect to traditional H.323 VoIP system smoothly. It differentiates node’s ability and decreases the output voice data transfer through public network VoIP servers. Those factors decrease the system cost. Author develops a tool, it can analyse runtime network status. We develop a tool that can be created a picture of network lost packages or latency to show all runtime network visual status report for user.
（3） The carrier grade method for P2PVoIP. All the while, people use P2P network for commercial goal is difficult. The major problem is how to control pay for service
workflow and make a good carried grade mode. The paper presents a method that every P2P nodes increase principle of authentication and account base on Remote Authentication Dial In User Service (RADIUS) protocol. By this interface the carrier grade which want to use the P2P network, can join the P2P network as a part easily.