Research On Searching Mechanism Of P2P Network Based On JXTA

The P2P (peer-to-peer) file sharing systems are widely applied because of its idea of freedom and equality of P2P technology. Effective way to find P2P resources is the premise of the full use of resources. Therefore, P2P searching technology becomes one of hot topic in P2P research field. Current development of P2P systems is a bit chaotic and there is no unified standard. JXTA provided unified standards for the development of P2P systems.The DHT algorithm is used by P2P searching technology based on JXTA. This algorithm will cause some problems, such as low search efficiency and high management costs. In terms of the defects and deficiencies of P2P searching technology based on JXTA, the technologies of P2P and JXTA are analyzed in this thesis and further works were done in the P2P searching technology based on JXTA. The primary works about improving searching efficiency and reducing management costs in this thesis are described as follows:Firstly, the concept of adaptive peer group is proposed. Adaptive peer group i is a collection of peers that have similar interests. Each adaptive peer group is maintained on certain scale. According to the definition of adaptive peer group, a strategy of the adjustment on adaptive peer group size is proposed. When the network size is too large or too small, adaptive peer group can be split or merged.Secondly, the Gnutella algorithm is improved on the basis of adaptive peer group, and the improved searching algorithm is applied to run in adaptive peer group. Gnutella algorithm is broadcast forward to query and it is only applied to small-scale network. Gnutella algorithm will lead to broadcasting storm and take up too much network bandwidth easily when the network size is too large. The improved Gnutella algorithm adds the auxiliary information to each node. In many cases, it can replace the broadcast forwarding with the selective forwarding. Thereby,it reduces the unnecessary waste of network resources and can quickly find resources. In this thesis, the improved Gnutella algorithm is tested by PeerSim simulation platform. The experimental data indicates that the improved Gnutella algorithm running in adaptive peer group can improve the searching algorithm performance.Thirdly, searching in other peer groups should be processed when the searching results do not meet for the conditions. In this case, to make search in other peer group more efficient, searching should be limited to peer group that has the similar interests with the local peer group. Therefore, a similarity algorithm of adaptive peer group is proposed.Fourthly, group peer view is established by the results of the similarity algorithm. Prioritized adaptive group searching mechanism (PAGS) is proposed on the basis of adaptive peer group, the improved algorithm Gnutella and group peer view. PAGS searching mechanism of specific searching control strategies is designed.Finally, according to the idea of PAGS searching mechanism, the overall design of the searching system is complemented and the key part of the searching system is accomplished. The searching system supports straightforward fuzzy queries, and its algorithm is simple and can reduce management costs to some extent. It has certain advantages compared with the traditional P2P searching based on JXTA.