P2p Systems Based On Ppadht Design

Nowadays how to utilize the information efficiently by fast developed network technique has become more and more important. The novel P2P sees great advantage on IM(instant message), file transport, distributed computing, and has wide prospect for application. DHT(distributed hash table) technique ,which has good expansibility and node self-organization ability, has become one of the hot research points in P2P research fields. However, these research all base their theories on the assume that all nodes in P2P systems have equal ability, which result in that some p2p nodes can't make full use of their abilities. Besides, DHT protocols are not convenient for the development and upgrade of application software as they have various apis. In this thesis, questions mentioned above are deeply studied. Considering the existence of heterogeneity of P2P network, we designed a fundamental framework of general P2P application. Main research works are as follows:We proposed a new overlay network protocol- PPADHT (Peer-Performance-Aware Distribute Hash Table). Compared with other DHTs, it can achieve logarithmical lookup hop counts by constant out-degree, and can get better balance between time cost and space cost.we designed a fundamental framework of general P2P application to simplify the difficulties of development in top application. Because of the design of delamination, the framework is scalable and compatible with all kinds of DHT algorithms. By introducing super peers, a schema, which supports obscure inquiry and can get more than 80% hit rate, is designed.Besides we analyzed the performance of PPADHT on storage load balance both in theory and in experiment. Results shows that PPADHT could balance the document load in the practical way. Furthermore we proposed 5 virtual node strategies, which can help peers in the same layer get better load balance performance.