Departmental Papers (CIS)

Date of this Version

February 2004

Document Type

Conference Paper


Postprint version. Published in Lecture Notes in Computer Science, Volume 3279/2005, Peer-to-Peer Systems III, 2005, pages 141-150.
Publisher URL:

NOTE: At the time of publication, author Boon Thau Loo was affiliated with the University of California at Berkeley. Currently (March 2007), he is a faculty member in the Department of Computer and Information Science at the University of Pennsylvania.


Popular P2P file-sharing systems like Gnutella and Kazaa use unstructured network designs. These networks typically adopt flooding-based search techniques to locate files. While flooding-based techniques are effective for locating highly replicated items, they are poorly suited for locating rare items. As an alternative, a wide variety of structured P2P networks such as distributed hash tables (DHTs) have been recently proposed. Structured networks can efficiently locate rare items, but they incur significantly higher overheads than unstructured P2P networks for popular files. Through extensive measurements of the Gnutella network from multiple vantage points, we argue for a hybrid search solution, where structured search techniques are used to index and locate rare items, and flooding techniques are used for locating highly replicated content. To illustrate, we present experimental results of a prototype implementation that runs at multiple sites on PlanetLab and participates live on the Gnutella network.



Date Posted: 08 March 2007