Grid Computing pp 275-286 | Cite as

Implementing Dynamic Querying Search in k-ary DHT-based Overlays

  • Paolo Trunfio
  • Domenico Talia
  • Ali Ghodsi
  • Seif Haridi

Distributed Hash Tables (DHTs) provide scalable mechanisms for implementing resource discovery services in structured Peer-to-Peer (P2P) networks. However, DHT-based lookups do not support some types of queries that are fundamental in several classes of applications. A way to support arbitrary queries in structured P2P networks is implementing unstructured search techniques on top of DHTbased overlays. This approach has been exploited in the design of DQ-DHT, a P2P search algorithm that combines the Dynamic Querying (DQ) technique used in unstructured networks with an algorithm for efficient broadcast over a DHT. Similarly to DQ, DQ-DHT dynamically adapts the search extent on the basis of the desired number of results and the popularity of the resource to be found. Differently from DQ, DQ-DHT exploits the structural constraints of the DHT to avoid message duplications. The original DQ-DHT algorithm has been implemented using Chord as basic overlay. In this paper we focus on extending DQ-DHT to work in k-ary DHT-based overlays. In a k-ary DHT, broadcast takes only O(logk N) hops using O(logk N) pointers per node. We exploit this “k-ary principle” in DQ-DHT to improve the search time with respect to the original Chord-based implementation. This paper describes the implementation of DQ-DHT over a k-ary DHT and analyzes its performance in terms of search time and generated number of messages in different configuration scenarios.


Peer-to-Peer resource discovery dynamic querying distributed hash tables 


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Copyright information

© Springer Science+Business Media, LLC 2008

Authors and Affiliations

  • Paolo Trunfio
    • 1
  • Domenico Talia
    • 1
  • Ali Ghodsi
    • 2
  • Seif Haridi
    • 2
  1. 1.DEIS University of CalabriaItaly
  2. 2.Swedish Institute of Computer ScienceSweden

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