Based On The Proximity P2p Routing Algorithm Design And Realization

P2P (Peer-to-Peer) network is a hotspot of the network research in the recent years. At present, most of the P2P network systems are constructed as overlay networks. Neighboring nodes in an overlay network are not necessarily close to each other or may even far away from each other in the underlying network, which may result in high routing delay between two nodes in the overlay network. Only if the entries in the routing table correctly represent the underlying network topology can the routing delay in the application level be reduced and the routing and network application performance be improved.This thesis first introduces several structured P2P routing mechanisms: Chord, CAN, Plaxton, Tapestry, Pastry and PGrid, and several unstructured P2P routing mechanisms: Napster, BitTorrent, Gnutella and FreeNet, and then focuses on the analysis of the PGrid routing algorithm. Aiming at the disadvantage of blind optimization, long optimization cycle and etc. of the maintenance method used in PGrid which selects routing table entries to optimize periodically and randomly, this thesis presents a new routing table maintenance algorithm called PNS-PGrid(proximity neighbor selection PGrid). In PNS-PGrid, the routing table maintenance task is invoked after a node has forwarded a request and the entry used at this time is optimized. The optimization cycle is adjusted according to whether the routing table entry reaches or is close to the optimization value. PNS-PGrid also incorporates the mechanism to handle the unwarned node failure and exceptional departure to maintain routing table. Experiment shows that PNS-PGrid algorithm can dynamically and pertinently adjust the entries in a node's routing table under a comparatively low cost and can reach the optimization value faster, which finally reduces routing delay and improves network performance.