Research On P2P Topology Construct Algorithm Based On DHT

P2P network is a kind of logical network which is established on the application layer and can make good use of the idle resource of network. The interconnect physical or logical relationships between each node form a P2P network topology in the network. In p2p network, the mismatched topology between the overlay network and physical network causes the increase in network flow, network congestion and decreases the efficiency of resource location. Therefore, we need to study the P2P network topology that can efficiently locate the resource and has a good scalability.The performance of p2p network depends on the structure of topology and methods of resource location. This article describes four major P2P network topology models, which are centralized topology, distributed unstructured topology, distributed structured topology and Semi-distributed structured topology, and analyse the advantages and disadvantages of the construction method on every model and the methods of resources location and nodes organization.The research lay on construction of structured topology based on DHT. After analysing the features of the typical structured topology model - Chord, this paper proposes a new model - a Virtual Two Layered-Chord model (VTLChord), and combines with physical characteristics of the network nodes to improve the algorithms of nodes organization, resource allocation and dynamic topology maintenance on VTLChord model.Combining the physical characteristics of the node’s gateway, VTLChord model mark nodes and locates the resource so that the same network segment nodes are adjacent on overlay network and avoid the repeated route on physical network, which makes the P2P system topology matched. The result of simulation proves that VTLChord achieves load balancing, improves the efficiency of resource location and ability of fault-tolerant.