Research And Improvement On Chord Of Structured P2P Routing Protocol Based On DHT

At present, Peer-to-Peer(P2P) is a research hotspot in distributed computing and computer network. There are many applications in this domain. The most critical problem in peer-to-peer network is how to search resources in a decentralized way while provide efficiency and scalability. This is the key of the system's capability and also the bottleneck of the P2P development. In view of this, various efficient algorithms are put forward by the researchers all around the world, including the Chord which based on structured DHT distributed lookup algorithm.This paper details the introduction of original Chord, analyses the Chord protocol basic concepts and characteristics. On this basis, put forward some better strategies of recourses lookup, aimed at routing table and the optimization of the lookup mode, including the following five modification manners.First of all, starting from the optimization of routing table, put forward two amendment programs. First, increasing the routing base number, and extending the bestrow rate of routing table. It will make the finger table denser and enlarge the query bound. Second, eliminating the redundance information in routing table, and adding new routing information which can enlarge query range. Second, improving the query method. It can reduce the residence time on the middle node, which can minish the latency when the originate sender lookups resource. Once again, establishing a model which combine the Chord system and proximity neighbor selection. Considering the approach of the physical topology, which makes Chord protocol take into account the approach of real network physical node. Finally, combining the two modifications that routing table optimization and the query improvement. Not only reduces the routing hops number, but also minishes the processing time of each hop, which can decrease the lookup latency.In order to verify the correctness of the theory modification, using the P2PSim platform to simulation comparison by the parameter of performance for the original protocol and the amendment protocols. It indeed proves that the amendment ways can effectively improve efficiency of resources lookup of Chord protocol. Simulation experiments show that the improvements emphasize particularly on different points, and supplement each other. In one word, these methods can a certain extent fulfill the need of applications.