Advanced Networks Colloquium: Christina Aperjis, "Peer-Assisted Content Distribution"
Friday, November 18, 2011
1146 A.V. Williams Building
301 405 6579
Advanced Networks Colloquium
Bilateral and Multilateral Exchanges for Peer-Assisted Content Distribution
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Users of the BitTorrent file-sharing protocol and its variants are incentivized to contribute their upload capacity in a bilateral manner: downloading is possible in return for uploading to the same user. An alternative is to enable multilateral exchange via a price-based market mechanism to match user demand for content to available supply at other users in the system. The two system designs present a significant tradeoff: bilateral exchange without money is simple, while multilateral exchange allows more users to trade. We provide a formal comparison of the two types of exchange both in terms of equilibria and through the expected percentage of users that can trade in a large system. Our theoretical results as well as analysis of a BitTorrent dataset provide quantitative insight into regimes where bilateral exchange may perform quite well even though it does not always give rise to Pareto-efficient equilibrium allocations.
This is joint work with Ramesh Johari and Michael J. Freedman.
Christina Aperjis received the B.S. degree in electrical and computer engineering from the National Technical University of Athens, Athens, Greece, in 2003, the M.S. degree in computer science from Columbia University, New York, NY, in 2004, and the Ph.D. degree in operations research from Stanford University, Stanford, CA, in 2009. She is currently a Researcher with the Social Computing Group, HP Labs, Palo Alto, Calif.