Research On Search Algorithms Of Resource In P2P And Its Application In Distance Education System

Recent years, a new network application model, P2P (Peer to Peer) has become more and more popular because of its outstanding advantages: augment-ability and highly fault-tolerance. Search mechanism, as the most core technology of P2P application, is to find out the most system nodes resources which can meet the requirements of customers as soon as possible in the P2P dynamic distributed environment.DHT (Distributed Hash Table) search algorithms is mainly adopted in the structured P2P network, it works fast and efficiently, but it is also limited by the network topology structure; the unstructured P2P network is widely applied, which based on flooding and index discovering mechanism, but flooding produces superfluous news and index lead to server failure and overload bandwidth.In view of the above questions, two aspects of research were done as following:(1)In unstructured P2P network, the network topology structure is quite uncertain; the ability of each peer is in great difference, such as its CPU rate, network bandwidth, lasting time on line, memory capacity, etc. A new method, to evaluate the peer capacity, was brought forward. In this method, the principle of evaluating the peer capacity was discussed.(2)After analyzing several traditional P2P search mechanisms, a new search mechanism——NAAT(Node Ability Automatically Fit) was invented, and then the principle, process and algorithms code of NAAT was showed. Experiment shows that NAAT makes the search mechanisms more efficiency.Based on NAAT, a P2P application model was deeply discussed, involving in design environment, system demand, system target, workflow, function module and program of each.According to the front P2P application model and practical project demand, a distance education system is designed and programmed, which is well applied at the network educational college of Center South University.