Title: HELC: a High Efficiency and Low Cost structured Peer-to-Peer overlay without Distributed Hash Table

Authors: Deng Li, Zhigang Chen, Hui Liu, Athanasios P. Vasilakos

Addresses: School of Information Science and Engineering, Central South University, Changsha 410083, Hunan Province, P.R.China. ' School of Information Science and Engineering, Central South University, Changsha 410083, Hunan Province, P.R.China. ' Department of Computer Science, Missouri State University, Springfield, MO 65897, USA. ' Department of Computer and Telecommunication Engineering, University of Western Macedonia, 531 00 Florina, Greece

Abstract: For such a highly distributed and heterogeneous environment as P2P system, information reflection and collection, lack of centralised control and non-cooperation are just some of the challenges. In order to build an ideal P2P system, there are two key problems to be solved: (1) how to make the overlay robust; (2) how information can be located and routed at a low cost without global view of the system. We have designed a hierarchical P2P overlay and combined its robust characteristic with the merits of a structured P2P overlay. Differing from the traditional hierarchical P2P tree-like structure, (1) this article presents a High Efficiency and Low Cost (HELC) structured P2P overlay composed of levels and layers, which uses small world characteristics to improve efficiency and decrease the cost of routing. (2) Unlike normal redundant mechanisms for solving the single fault problem: Tri-Information Center mechanism is presented to improve robustness. (3) A source ranking mechanism is proposed to discourage free riding and whitewashing and to encourage frequent information exchanges among peers. The HELC will be not only more efficient because it applies the DHT-like routing algorithm in the unstructured P2P overlay, but also more adaptive to suit highly dynamic environment.

Keywords: distributed hash tables; DHT; information centres; source ranking; peer-to-peer overlay; structured P2P overlay.

DOI: 10.1504/IJAACS.2008.019200

International Journal of Autonomous and Adaptive Communications Systems, 2008 Vol.1 No.1, pp.55 - 81

Published online: 02 Jul 2008 *

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