Search Algorithm And Other Network Resources

As a new distributed computing paradigm, P2P (Peer-to-Peer) networks are widely used in resources sharing, instant communications and collaborative work. Each peer node in P2P network has the same function which can provide services as a server and receive services as a client, direct communication and file transfer can be achieved between any two nodes. Resources in P2P network are stored in each node, an effective resources search mechanism is the key for efficient resources management. P2P models are divided into centralized model, decentralized unstructured model and decentralized structured model, the algorithms of resources search are different in different models.The main works of the paper are as follows:(1)P2P models are summarized, the algorithms of resources search in unstructured P2P networks and structured P2P networks are described and analyzed.(2) An improved algorithm——resources search algorithm for unstructured P2P networks based on shortcuts between the subtrees of the root is proposed to solve the problems of producing a large number of redundant messages and localized search in the process of resources search in unstructured P2P networks. The algorithm structures a topology with a multi-way balanced tree and creates shortcuts between the subtrees of the root in the routing level. By designing the corresponding strategies of nodes insert, exiting network and resources search strategies, the algorithm can reduce the amount of redundant messages effectively in the process of resources search and has higher resource search success ratio in the case of smaller TTL. The introduction of shortcuts between the subtrees of the root not only ensures forward message without relying on the root in the process of resources search, but also reduces the average length of the search path. Finally, the experiments verify the effectiveness of the algorithm.(3)An algorithm of resources search in structured P2P network—resources search algorithm for structured P2P networks based on shortcuts between the subtrees in the same level is proposed. The algorithm also structures a topology with a multi-way balance tree and creates shortcuts between the subtrees in the same level in the routing level. By designing the corresponding strategies of nodes insert, exiting the network and resources search strategies, the algorithm has shorter average length of the search path in the process of resources search compare to other typical structured P2P networks. The introduction of shortcuts between the subtrees in the same level ensures forward message without relying on the root in the process of resources search. Finally, the experiments verify the effectiveness of the algorithm.