Dr. Dahai Xu

The classical multi-commodity problem is to minimize a convex objective function of link utilizations for a given set of traffic demands. An open problem was whether and how to realize its optimal solution using a destination-based, hop-by-hop forwarding, where each node independently determines traffic splitting across its outgoing links based on a global view of link weights. We proved that any optimal multi-commodity flow can be realized with a new link-state routing protocol, PEFT, using uneven traffic splitting. PEFT was derived from a new convex optimization problem, Network Entropy Maximization (NEM), which involves an infinite number of variables. In this talk, we present the compact and equivalent formulation of the NEM problem. But the question left is if NEM is the ONLY additional objective function to realize optimal flow with link-state routing.

Biography: Dr. Dahai Xu is currently a research staff in AT&T Labs. After receiving his Ph.D. degree in Computer Science and Engineering from University at Buffalo in 2005, he spent two years as a postdoctoral research associate in Department of Electrical Engineering at Princeton University. His research interests include Internet design, control and management; Algorithm design and fast implementation; Large-scale non-linear network optimization; Secure communication in wireless ad hoc networks. More information can be found at http://www.research.att.com/~dahaixu/.