Research And Design Of VoIP System Architecture Based On P2P Technology

VoIP (Voice over IP), a voice service with some extent of QoS and transmitted over IP, has developed into a new service of IP networks in recent years. With the development of IP technology, telecommunication network has also been operating over IP, therefore voice service of telecommunication network is also VoIP. However, the traditional telecommunications network uses a centralized Client/Server architecture, which has high cost, low scalability, the difficulty to share resources and so on. To deal with this situation, we make a deep research on the VoIP architecture drawing on the great success of P2P technology in Internet, and propose P2P VoIP network architecture with carrier-class operational capabilities.In order to meet the requirements of P2P VoIP, we first propose the hierarchical model of P2P VoIP, which includes basic resource layer, control layer, application layer and operating support layer. Based on that, we propose a scalable P2P VoIP interconnection architecture. This architecture is very flexible and can be deployed in a variety of scenarios, and can interoperate with existing networks, such as PSTN, PLMN and IMS.P2P VoIP adopts DHT (Distributed Hash Table) as a distributed location index, which increases the session setup latency and session setup overhead in some extent. To reduce the latency and overhead, this paper proposes a two-level network architecture and designs the Adaptive DHT algorithm. The simulation results show that the session setup latency and session setup overhead are significantly reduced after using the Adaptive DHT algorithm.Based on the two-level network architecture and the Adaptive DHT algorithm, this paper proposes an intra-domain load transfer strategy which is responsible for temporary overload caused by node's join and exiting, and inter-domain load transfer strategy which is responsible for a large amount of overload caused by emergencies, such as earthquake. Finally, simulation results show that it can significantly improve the success rate of customer service after using the load transfer strategy, and meanwhile, it will not bring too much overhead as well as resource occupation of objective domain which could still provide users a good service with QoS assurance.