Research On Fault-tolerance Of Decentralized Unstructured Peer-to-peer

At present the P2P network popular in the network research domain is one kind of new network model. As the pure distributed computing technology, its application has extended to the distributed computing, the cooperative work, the distributional search, file sharing, the game and the immediate communications system and so on. It has broad application foreground. In these models of P2P network applications, the unstructured P2P network application has accounted for the very great proportion, In unstructured P2P network the node joins the network disorderly, which causes the unstructured P2P network to lack the reliable network topology and the valid search strategy, therefore, studying the reliable network topology become important topic in unstructured P2P network.This article first summarizes the some interrelatedwork of topology and the search strategy of the unstructured P2P network, and introduce three category of P2P network ( Centralized Topology , Decentralized Structured Topology and Decentralized Unstructured Topology) , we analyze the fault-tolerance of three category of P2P network's topology and advance the ameliorative way of Unstructured P2P about fault-tolerance strategyAt present because the unstructured P2P network can not validly carry on in the network topology about the fault-tolerant of node and cannot balance the contradiction of the network scale and the route efficiency very well, therefore, according to the principle of biconnected graph and minimum connected dominating set of graph theory this article proposes fault-tolerant model based on Gnutella - BGFP (Biconnect Graph Fault_tolerance P2P) of unstructurize P2P network, this model adopts the thought of biconnected graph, and establishes the biconnected subgraph through the single node to form the network topology , at the same time the single node undertook the maintenance of biconnect sub- graph, In the base of the establishment network topology ameliorative Distributed Approximation Algorithm for Minimum Connected Dominating Set is advanced ,the BGFP will make the single nodes build Connected Dominating Set,by Connected Dominating Set the BGFP forms a transmission backbone network to reduce the searching area , because the establishment and the maintenance of system topology and the transmission backbone network all establishe in the base of the single node, the building process only needs the local network state information, therefore, the model not only has the good fault-tolerance and the performance of reducing system loading.