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Peer-to-Peer Swarming for Multi-Commodity Dissemination

13 May
Thursday, 05/13/2010 6:00am to 8:00am
Ph.D. Dissertation Proposal Defense

Daniel Menasche

Computer Science Building, Room 151

Peer-to-peer swarming, as used by BitTorrent, is one of the de facto solutions for content dissemination in today's Internet. By leveraging resources provided by users, peer-to-peer swarming is a simple, scalable and efficient mechanism for content distribution. Although peer-to-peer swarming has been widely studied for one decade, prior work focused on the dissemination of one commodity (file). This thesis focuses on the multi-commodity case.

We have discovered through measurements that a vast number of publishers currently disseminate multiple files in a single swarm (bundle). The first contribution of this thesis is a model for content availability. We use the model to show that, when publishers are intermittent, bundling K files increases content availability exponentially as function of K. When there is a stable publisher, that control prices and bundling strategies, we present conditions for the existence and uniqueness of an equilibrium between such a publisher and peers. Then, we investigate reciprocity and the use of barter that occurs among peers. As our second contribution, we prove that the loss of efficiency due to direct reciprocity, as opposed to indirect reciprocity, is at most two in a class of networks without relays. Our third contribution is the estimate of the dependency of peers on a stable publisher, which is useful for provisioning purposes as well as in deciding how to bundle. To this goal, we propose a new metric, swarm self-sustainability, and present a model that yields swarm self-sustainability as a function of the file size, popularity and service capacity of peers.

Advisor: Don Towsley