IMPastry:An Improved Model Based On Pastry System

In a P2P (Peer to Peer) network, the peers are computing systems which are connected to each other via the network. Files can be shared directly between systems in the network without the need of a central server. Each equal peer node in P2P network simultaneously functions as both"client"and"server"to other peers in the network. Now, the development of peer to peer network has been generating tremendous impact on networks infrastructure itself.As a key aspect of the P2P network, resource locating technology is always being the focus in academic researches. Commonly, P2P networks can be classified by using the different locating technology, and DHT is one of the most significant methods for locating. In this paper, we discuss the typical P2P systems based on DHT, such as CAN, Chord, Tapestry and Pastry, and then have a deep insight of each system in the system routing, node joining and departing.According to the analysis of the existing DHT based P2P network systems, we can conclude that the logical overlay network is inconsistent with the realtime physical networks, which could cause the resource locating inefficiently, and then affect the performance of the P2P network system. To alleviate the symptom mentioned above, we introduce an IMPastry (Identical Mapping Pastry) P2P system that is based on the Pastry system. By adjusting the system for the peer node ID generation, IMPastry can easily build an identical mapping relationship between the overlay network and physical networks. In this relationship, the peer nodes which are near to each other in physical network are still adjacent with each other in overlay network. In addition, IMPastry has made several modifications to adapte to the identical mapping relationship.