Research And Improvement On P2P Network Resources's Location Algorithm

Peer-to-peer network is becoming a hot topic dramatically in recent years.Various applications are developed base on it.Peer-to-peer network can provide unlimited storage and network bandwidth,which is unthinkable in traditional centralized server. The nodes in peer-to-peer network work as both service provider and consumer.Nodes cooperate and share resources with a totally distributed and symmetric algorithm. Hereby the core of the networks' application is moved from central server to those terminal devices distributed in the edge of network.The most critical problem in peer-to-peer network is how to search resources in a decentralized way while provide efficiency,security and scalability.We can divide all existing search method into two categories:Flooding and DHT(Distributed Hash Table) based.Gnutella is a typical flooding protocol.But it is proved to be unscalable in practice.Although many efforts were devoted to control the broadcast package in flooding algorithm.So,many study turns to DHT.Plaxton,Tapstry,Pastry,CAN,Chord are all excellent represents of them. Chord is featured with its high performance in continuous changing network,which is vitalin most peer-to-peer environment.This paper carefully analysised and researched the classic chord algorithm firstly. And have pointed out algorithmic advantage of classics Chord and its limitation. Specifically for algorithmic limitation of classic chord,the author of the paper creatively have brought forward one kind of new Chord algorithm model—NChord,and analysised the resource allocation-seeking,nodes development changing in this new model for detail.And this model have perfect super node defends mechanism that guarantees the model stability.At the same time in order to prevent the node after the data packet localized problems,the model for the super-node cache table has increased,thereby reducing the frequency of interaction both within and outside the network and resources to speed up the popular search efficiency,greatly enhanced the resources to find the same efficiency.In order to verify the performance of NChord,a program was made based on NS-2 to simulate NChord.The simulation result shows that NChord do bring better performance than original Chord.