Georgia Tech: Networking & Telecommunications Group


 
Title Flow level performance of bandwidth sharing networks in overload
Speaker Bert Zwart
Abstract

A well-engineered network should not experience overload, or even approach overload, in normal operating conditions. Yet, even in an adequately provisioned system with a low nominal load, the actual traffic volume may significantly fluctuate over time and exhibit temporary surges. This phenomenon can have negative impact on network performance, leading to phenomena like user impatience.

Motivated by this, we consider flow level bandwidth sharing models and assume that at least of the associated links is overloaded. Traditional stochastic processor-sharing type models are not tractable enough to yield structural insights. We therefore derive tractable fluid approximations that enable us to investigate system performance.

The first part of this talk focuses on a single link model taking user impatience into account. After that, we consider extensions to networks.

References:

C. Gromoll, Ph. Robert, B. Zwart, R. Bakker. The impact of reneging in processor sharing queues. In ACM-Sigmetrics, Saint Malo, June 2006.

R. Egorova, S. Borst, B. Zwart. Bandwidth sharing networks in overload. Submitted for publication.

Bio

Bert Zwart is an associate professor and Coca-Cola junior professor at ISyE since 2006. Dr. Zwart graduated in 1997 with an M.A. degree in Econometrics at the Vrije Universiteit, Amsterdam, The Netherlands. He carried out his Ph.D research at Eindhoven University of Technology and theCenter for Mathematics and Computer Science. For his Ph.D thesis 'Queueing Systems with Heavy Tails', he received the Applied Probability Trust award (2001), the ASML prize for best Ph.D thesis in Einhoven in 2002, and the Gijs de Leve prize for best Ph.D thesis in Operations research (in the Netherlands, from 2000-2002).

In the academic year 2001-2002, he spend a postdoctoral fellowship at INRIA, Rocquencourt, France. From 2002-2006, Bert Zwart was on the faculty of the math and CS department of Eindhoven University of Technology as VENI fellow and assistant professor. He serves on the editorial boards of several international journals.