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Understanding the Properties of the BitTorrent Overlay

Anwar Al Hamra 1 Arnaud Legout 1 Chadi Barakat 1
1 PLANETE - Protocols and applications for the Internet
Inria Grenoble - Rhône-Alpes, CRISAM - Inria Sophia Antipolis - Méditerranée
Abstract : In this paper, we conduct extensive simulations to understand the properties of the overlay generated by BitTorrent. We start by analyzing how the overlay properties impact the efficiency of BitTorrent. We focus on the average peer set size (i.e., average number of neighbors), the time for a peer to reach its maximum peer set size, and the diameter of the overlay. In particular, we show that the later a peer arrives in a torrent, the longer it takes to reach its maximum peer set size. Then, we evaluate the impact of the maximum peer set size, the maximum number of outgoing connections per peer, and the number of NATed peers on the overlay properties. We show that BitTorrent generates a robust overlay, but that this overlay is not a random graph. In particular, the connectivity of a peer to its neighbors depends on its arriving order in the torrent. We also show that a large number of NATed peers significantly compromise the robustness of the overlay to attacks. Finally, we evaluate the impact of peer exchange on the overlay properties, and we show that it generates a chain-like overlay with a large diameter, which will adversely impact the efficiency of large torrents.
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Contributor : Arnaud Legout Connect in order to contact the contributor
Submitted on : Thursday, July 12, 2007 - 1:30:15 PM
Last modification on : Thursday, February 24, 2022 - 3:34:03 PM
Long-term archiving on: : Thursday, April 8, 2010 - 11:05:01 PM


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  • HAL Id : inria-00162088, version 1
  • ARXIV : 0707.1820



Anwar Al Hamra, Arnaud Legout, Chadi Barakat. Understanding the Properties of the BitTorrent Overlay. [Technical Report] 2007, pp.18. ⟨inria-00162088⟩



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