He received a PhD from Harvard University for work on modeling and controlling networks with large numbers of competing connections. As a graduate student he helped design and build an ARPA-funded ATM switch with per-circuit hop-by-hop flow control. He led a mobile communication project which won a best student paper award from USENIX. He co-founded Viaweb, an e-commerce hosting service. His current interests include modular software-based routers, analysis of the aggregation behavior of Internet traffic, and scalable ad-hoc routing.