Systems without Cooperation

March 18, 2010
Dave Levin | University of Maryland

The Internet is no longer the cooperative, technological playground it once was. Successful networked systems must account for potentially competing interests. In this talk, I will present two systems that together demonstrate that economic theory, and in particular auctions, can be a powerful means of analyzing and improving incentives for self-interested users to cooperate.

First, I will show that the popular BitTorrent system uses, not tit-for-tat as widely believed, but an auction to decide which peers to serve. This model captures known performance-improving strategies, and shapes our thinking toward new, effective incentive mechanisms.

Second, I will present Hoodnets, a system that allows mobile phone users to bond their low-bandwidth cellular connections into high-bandwidth connections. Hoodnets employs auctions to give users incentive to forward traffic for one another, overcoming the likely reluctance of sharing their costly links. With a real-world implementation of Hoodnets, I will demonstrate that, in practice, two complementary auction mechanisms are necessary to support both long-lived flows and bursty traffic.

These two systems together demonstrate the importance of aligning the assumptions of economics and large-scale systems. Doing so allows us to develop new mechanisms that foster cooperation among the otherwise self-interested.

Speaker Details

Dave Levin is a PhD candidate at the University of Maryland, advised by Bobby Bhattacharjee, Neil Spring, and Aravind Srinivasan, and is a Microsoft Live Labs fellow. Dave was an intern the past two summers at MSR with the Distributed Systems and Security group. His research interests include achieving cooperation among self-interested parties, protecting user privacy, and the practical application of theoretical tools like economic theory to large-scale systems.