An Overlay Network For DHT-based P2P File Locating Service

A new form of network has come into being,which is called Peer-to-Peer network.Peer-to-Peer network breaks the traditional model of Client/Server.Each node not only plays a role of server that provides the service but also plays a role of client that enjoys the uses of re sourses in Peer-to-Peer network. Recently, there are many research interests in the P2P overlay networks'location. Structured P2P networks use the distributed hash tables (DHTs) to provide efficient mechanism for resource location. However, the structured P2P networks are not aware of the nodes locality. As a result, under this architecture, nearby nodes in the overlay network may actually be far away in the underlying network.Based on these problems, we make a research on these challenging problems of DHT technique when it is applied on P2P systems. We resolve these challenging problems without the loss of nice performance of DHT technique, so as to break through the limitation of DHT technique. The contribution of this dissertation is in the following aspects.1. Adjusting mechanism of P2P overlay network, constructing an overlay network-LAOverlay that takes account of locality of network. LAOverlay takes account of the nodes locality, joins the nearby nodes into a group. Resources position and resources location are working under this mechanism.2. A new method of resource position is presented in this paper. It expanded the DHT technology, used dual backup of resources: backup inside and backup outside, so it enhanced the resources localization efficiency.3. A new method of resource location is presented in this paper. This method first locates in local group that nodes are nearby, and then locates in outside group. Also LAOverlay still considers data'local character, resouces will re-positioning in local group when the node locate this resouce in other group.4. We use planetSim to simulate.The thesis takes its focus on the overlay layer in light of the complex and impracticable work at the protocol layer simulation.This system provides an efficient file locating with high scalability and efficiency and self-organization. Theoretical analysis shows that this architecture has significant performance improvements compared to DHT system in average searching hops. Our proposed locality-aware overlay can used in many large-scale network applications, like media streaming, application-level steaming.