The Study And Majorization Of Strucutred P2P Searching Algorithm

P2P is called peer to peer or peer-to-peer network. Using P2P network, people can connect to other users of computers directly to exchange files and don't need to link to servers to browse and download files as past.With the development of P2P, structured P2P topology becomes a trend because of its clarity and regularity. Meanwhile, because searching technology is the most valuable subject of study in P2P, structured P2P searching technology receives more attentions by people. Among the structured P2P searching algorithm, Chord algorithm has been widely applied to P2P systems for its simplicity of design.The goal of this paper is to study Chord algorithm, analyze its shortcomings and put forward the idea of Bidirectional-and-noredundancy inquiring and Middle-node-table. The improved idea refractors the finger tables of all nodes in the Chord ring and eliminates duplicate entries of finger tables. So it increases the hit rate of resources directly. Because Bidirectional-and-noredundancy inquiring brings about some defects, this paper introduces a new structure called Middle-node-table. This improvement of Chord not only expands the coverage of finger table, but also improves location accuracy of resources. At last, the paper uses simulation results to show that compared to the original algorithm, the improved algorithm has more advantages in the average time delay and average length of searching path.Firstly, this paper states the advantages of P2P technology compared with traditional C/S technology. Secondly, it compares the structured P2P with non-structured P2P network and its relevant searching algorithm, and then discusses the classical searching technology of structured P2P—DHT and the related knowledge of classical algorithm based on DHT. It also points out the existing problems and defects in Chord algorithm. Then realizes the improved algorithm and does theory and code analysis. At last, the paper compares the improved algorithm with the original algorithm in the P2P simulator and proves its advantages in decreasing the average length of searching path and in reducing the time delay.