[bittorrent] Evaluation of the BitTorrent choking algorithm
Arnaud.Legout at sophia.inria.fr
Tue Nov 21 16:57:20 EST 2006
I am pleased to announce the availability of the technical report:
Clustering and Sharing Incentives in BitTorrent Systems
Any comments are welcomed.
Peer-to-peer protocols play an increasingly instrumental role in
Internet content distribution. Consequently, it is important to gain a
full understanding of how these protocols behave in practice and how
their parameters impact overall performance. We present the first
experimental investigation of the peer selection strategy of the popular
BitTorrent protocol in an instrumented private torrent. By observing the
decisions of more than 40 nodes, we validate three BitTorrent properties
that, though widely believed to hold, have not been demonstrated
experimentally. These include the clustering of similar-bandwidth peers,
the effectiveness of BitTorrent's sharing incentives, and the peers'
high average upload utilization. In addition, our results show that
BitTorrent's new choking algorithm in seed state provides uniform
service to all peers, and that an underprovisioned initial seed leads to
the absence of peer clustering and less effective sharing incentives.
Based on our observations, we provide guidelines for seed provisioning
by content providers, and discuss a tracker protocol extension that
addresses an identified limitation of the protocol.
Arnaud Legout, Ph.D.
INRIA Sophia Antipolis - Planète Phone : 00.33.4.92.38.78.15
2004 route des lucioles - BP 93 Fax : 00.33.4.92.38.79.78
06902 Sophia Antipolis CEDEX E-mail: arnaud.legout at sophia.inria.fr
FRANCE Web : http://www-sop.inria.fr/planete/Arnaud.Legout/index.html
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