Stanford Networking Seminar

16:00PM, Wednesday July 8, 2009
Gates 104

Systems Without Cooperation

Dave Levin
University of Maryland

About the talk:
Decentralized systems that rely on users to contribute their resources have been remarkably successful, yet we can no longer assume altruism or benevolence of every participant in today's Internet. I will present two systems that prevent participants in a decentralized system from deviating from the letter and spirit of a protocol. These two examples together demonstrate the need to explore versatile, composable mechanisms to combat selfish and malicious behavior.
First, I will discuss the use of game theory to keep selfish users from gaining at the expense of others. 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 or thinking toward new, effective incentive mechanisms. Second, I will discuss the use of trusted hardware to keep both selfish and malicious users from lying in a distributed system. I will present TrInc (Trusted Incrementer), a small piece of trusted hardware intended for use in large-scale distributed systems. With case studies and an implementation, I will demonstrate that TrInc is a practical primitive for a wide range of systems.

About the speaker:
Dave Levin is a PhD candidate at the University of Maryland, advised by Bobby Bhattacharjee and Aravind Srinivasan, and is a recent Microsoft Live Labs fellow. His research interests include providing incentives to selfish users to participate in a network, modeling and tracing wireless networks, and the practical application of theoretical tools like economic theory to large-scale systems design.