Research And Application Of Distributed Hash Algorithm In P2p Network

P2P technology is one of the most popular in recent years of the computer network, there are so many internet applications based on P2P technology, BT, Emule and other share resources software applications is very widely used. The application based on P2P technology also includes a distributed storage, shared computing power and application layer multicast.So there are many applications require that the P2P system architecture must been desinged of scalability, fault tolerance, maintainability. The efficiency of search algorithm is put forward high demand. And the system based on distributed hash table (DHT) in the structured P2P architecture with high scalability, high reliability, low overhead and support the mass nodes and data features to meet the needs of these applications.Distributed architecture of the network is commonly used to build P2P networks using DHT algorithm, for instance, Chord, CAN, Kademlia, Tapestry, Pastry, etc. These algorithms not only possess high reliability and strong fault tolerance, but also have efficient look up . The complexity of search algorithm is basically O(LogN), so they are widely used in a variety of distributed storage systems. But the structured P2P network based on DHT algorithm also have many problems, including the maintenance mechanism of DHT. It used to be a complex when nodes frequently join the P2P network or leave the network caused fluctuations significantly and affected the performance of P2P network, increase the DHT maintenance costs. While in certain applications, you can modify and optimize the appropriate DHT algorithm, to a certain extent, and improve the efficiency of P2P systems.This paper study and compare the principles and differences of above DHT algorithms, research and analysis the Chord algorithm more in-depth. Chord algorithm is using the identifier which generated by consistent hash function, and designing its own routing table, providing a very efficient routing algorithm to improve the search speed. However, its routing table process is quite complex, and it also ignores the the difference between the logical network and the real network, besides the data security should be improved. Accordingly on the Chord algorithm, this paper present the maintenance of routing table, manage the hash space and allocate the identifier manually. According to the existing P2P simulation tool, we design the experiment using multi-threading technology to simulate the multi-nodes, and design a more realistic network topology and failure model to simulate the dynamics of the network. Finally the experimental results were compared and analyzed. In addition we study on the applicaton based on the DHT algorithm.