P2p Networks Based On Distributed Hash Table (dht)

P2P is one of the hottest topics in today抯internet world. There are dozens of internet applications based on P2P infrastructure, such as Bittorrent, Emule, KaZaA and Freenet, etc. Some of them were widely distributed and deployed over the internet. Besides file sharing, there are many other P2P applications including distributed file system, distributed computing, application level multicast and so on. The infrastructure for such applications should be expected to offer strong stability, global scalability, higher efficiency and some other features for running service on dynamic, failure-prone network environment. Tapestry and Pastry are representative Distributed Hash Table(DHT) based P2P overlay networks that provides high-performance, scalable and location-independent routing of messages to close-by endpoints, using only localized resources. A new generation of applications have been proposed on top of DHT systems, validating them as novel application infrastructures.The main discussion about DHT schema is the sophisticated maintenance mechanism of DHT, especially when a large amount of nodes failure/departure simultaneously, which is named Churn. This thesis pays most attention to the mechanisms of addressing Churn problem and gives the detail design of such mechanisms through an implementation of Tapestry infrastructure. Despite of the high load and a lot of failure nodes, these mechanisms prove the performance of the system and eliminate the request for global information, single point failure and poor fault-resilient as well.This papers accomplished a review, comparison and implementation of various P2P schemas. It also presents a Tapestry based P2P application by researching the major DHT infrastructure like Chord, CAN, Pastry and Tapestry. The availability of DHT based decentralized structured topology is proved as well.