As a solution for data storage and information sharing for peer-to-peer(P2P)networks,a novel distributed hash table(DHT)structure called PChord is presented in this paper.PChord adopts a bi-directional searching mecha...As a solution for data storage and information sharing for peer-to-peer(P2P)networks,a novel distributed hash table(DHT)structure called PChord is presented in this paper.PChord adopts a bi-directional searching mechanism superior to Chord and enhances the structure of the finger table.Based on Hilbert space filling curve,PChord realizes the mapping mechanism for multikeyword approximate searching.Compared with the Chord and Kademlia protocols,PChord evidently increases speed on resource searching and message spreading via theoretic proof and simulation results,while maintaining satisfactory load balance.展开更多
The maintaining overheads of Distributed Hash Table (DHT) topology have recently received considerable attention. This paper presents a novel SHT (Session Heterogeneity Topology) model, in which DHT is reconstructed w...The maintaining overheads of Distributed Hash Table (DHT) topology have recently received considerable attention. This paper presents a novel SHT (Session Heterogeneity Topology) model, in which DHT is reconstructed with session hetero- geneity. SHT clusters nodes by means of session heterogeneity among nodes and selects the stable nodes as the participants of DHT. With an evolving process, this model gradually makes DHT stable and reliable. Therefore the high maintaining overheads for DHT are effectively controlled. Simulation with real traces of session distribution showed that the maintaining overheads are reduced dramatically and that the data availability is greatly improved.展开更多
Peer-to-peer (P2P) systems are now very popular. Current P2P systems are broadly of two kinds, structured and unstructured. The tree structured P2P systems used technologies such as distributed hash tables (DHT) and h...Peer-to-peer (P2P) systems are now very popular. Current P2P systems are broadly of two kinds, structured and unstructured. The tree structured P2P systems used technologies such as distributed hash tables (DHT) and hierarchical clustering can search the required target quickly, however, in a tree, the internal node has a higher load and its leave or crash often causes a large population of its offspring's problems, so that in the highly dynamic Internet environment the tree structure may still suffer frequent breaks. On the other hand, most widely used unstructured P2P networks rely on central directory servers or massive message flooding, clearly not scalable. So, we consider both of the above systems' advantages and disadvantages and realize that in the P2P systems one node may fail easily, but that when a number of nodes organized as a set, which we call "super node", the set is robust. Super nodes can be created and updated aware of topology-aware, and used with simple protocol such as flooding or "servers" to exchange information. Furthermore the entire robust super node can be organized into exquisite tree structure. By using this overlay network architecture, P2P systems are robust, efficient, scalable and secure. The simulation results demonstrated that our architecture greatly reduces the alteration time of the structure while decreasing the average delay time, compared to the common tree structure.展开更多
基金supported by the National Natural Science Foundation of China (Grant No.60773041)the Natural Science Foundation of Jiangsu Province,China (No.BK2008451)+6 种基金the National High Technology Research and Development Program of China (No.2006AA01Z219)the High Technology Research and Development Program of Nanjing City (Nos.2007RZ106,2007RZ127)Foundation of National Laboratory for Modern Communications (No.9140C1105040805)Project supported by the Natural Science Foundation of the Jiangsu Higher Education Institutions of China (No.07KJB520083)Special Fund for Software Technology of Jiangsu Province,Post-doctoral Foundation of Jiangsu Province (No.0801019C)Science&Technology Innovation Fund for Higher Education Institutions of Jiangsu Province (Nos.CX08B-085Z,CX08B-086Z)the six kinds of Top Talent of Jiangsu Province.
文摘As a solution for data storage and information sharing for peer-to-peer(P2P)networks,a novel distributed hash table(DHT)structure called PChord is presented in this paper.PChord adopts a bi-directional searching mechanism superior to Chord and enhances the structure of the finger table.Based on Hilbert space filling curve,PChord realizes the mapping mechanism for multikeyword approximate searching.Compared with the Chord and Kademlia protocols,PChord evidently increases speed on resource searching and message spreading via theoretic proof and simulation results,while maintaining satisfactory load balance.
基金Projects supported by the Science & Technology Committee of Shanghai Municipality Key Technologies R & D Project (No.03dz15027) and the Science & Technology Committee of ShanghaiMunicipality Key Project (No. 025115032), China
文摘The maintaining overheads of Distributed Hash Table (DHT) topology have recently received considerable attention. This paper presents a novel SHT (Session Heterogeneity Topology) model, in which DHT is reconstructed with session hetero- geneity. SHT clusters nodes by means of session heterogeneity among nodes and selects the stable nodes as the participants of DHT. With an evolving process, this model gradually makes DHT stable and reliable. Therefore the high maintaining overheads for DHT are effectively controlled. Simulation with real traces of session distribution showed that the maintaining overheads are reduced dramatically and that the data availability is greatly improved.
基金Project (Nos. 60502014 and 60432030) supported by the National Natural Science Foundation of China
文摘Peer-to-peer (P2P) systems are now very popular. Current P2P systems are broadly of two kinds, structured and unstructured. The tree structured P2P systems used technologies such as distributed hash tables (DHT) and hierarchical clustering can search the required target quickly, however, in a tree, the internal node has a higher load and its leave or crash often causes a large population of its offspring's problems, so that in the highly dynamic Internet environment the tree structure may still suffer frequent breaks. On the other hand, most widely used unstructured P2P networks rely on central directory servers or massive message flooding, clearly not scalable. So, we consider both of the above systems' advantages and disadvantages and realize that in the P2P systems one node may fail easily, but that when a number of nodes organized as a set, which we call "super node", the set is robust. Super nodes can be created and updated aware of topology-aware, and used with simple protocol such as flooding or "servers" to exchange information. Furthermore the entire robust super node can be organized into exquisite tree structure. By using this overlay network architecture, P2P systems are robust, efficient, scalable and secure. The simulation results demonstrated that our architecture greatly reduces the alteration time of the structure while decreasing the average delay time, compared to the common tree structure.