The Study And Improvement About Search Algorithm Based On The Chord

In recently P2P technology have a great development. It take the ability of nodes distributed in the edge of net to generate very powerful computing and storage capacity.P2P completely changed the appearance of resource sharing technology and behavior. It can be widely applied in the area of file exchange, distributed computing, collaborative development which all has good potentiality. The nodes in the P2P architecture network both enjoy the services of other nodes provided,also provides its own services to the other nodes. The key point about P2P technology is how to keep the absence of a lock of central index server to help find the positioning of shared content with guarantee the robustness efficiency, and extensibility in the system. There are two ways to solve the current of technology puzzle:one is take the application of flood propagation algorithm which is used by Gnutella in which all kind net performance is good. But this way will consume very large Bandwidth which is intolerable in a very large-scale network. Another method is use the DHT which including CAN, Pastry, Chord.All above is DHT's sub-variant algorithm. Chord algorithm invented by MIT has a good network Performance in application specially in the situation of network's node change very frequently.After carefully analysis performance study we sum up the traditional Chord's algorithm advantages and disadvantages.we also design a new alternative algorithm model:N-Chord to cover it's disadvantages, while carefully explained how to locate the resource content and find the next node with new algorithm and the flow about node join and exit the network. Creating the super node protection can ensure the robustness of the model. Increasing the cache table to take advantage of temporal locality of data sharing to reduce the problem of frequent access to packet networks, while improved download speeds and locate hot shooting. Finally, to verify the N-Chord model significantly enhance the network performance. We use the P2Psim software to simulate the N-Chord algorithm simulation system model. After running the system the theory which N-chord take a marked improvement in performance in the average search length and the average delay is proved.