University of Minnesota
University Relations
myU OneStop

Go to unit's home.

Home | Seminars and Symposia | Past seminars/symposia: Tuesday, November 11, 2003

DTC Science and Technology Innovators Lecture Series

Can We Model the Internet?


Don Towsley
Computer Science
University of Massachusetts
Amherst, MA

Tuesday, November 11, 2003
4:30 p.m. Reception
5:00 p.m. Seminar

402 Walter Library

Don TowsleyDownload slides (pdf 613 KB) As the Internet continues to grow in size and complexity, it is commonly believed among engineers that it is extremely difficult, if not impossible, to model and analyze the Internet. This has resulted in an increased reliance on brute force simulation with little regard paid to careful model design. In this talk, I will argue that yes, simple models suffice to analyze various aspects of the Internet. This comes with a caveat of course; one needs to start with some understanding of the phenomena of interest. I will illustrate this through three examples. The first relates to the problem of designing end-to-end congestion control and the second relates to the problem of analyzing the performance of large, high bandwidth networks. Both of these share a common modeling paradigm — fluid models. I will then shift gears and describe how simple models can be used to make inferences of link behavior within a network.

Towsley presenting

These examples illustrate the power of simple models in network design and analysis. They are not without their pitfalls however. At the end of the talk, I will describe some of these pitfalls and provide some guidelines for avoiding them.


Towsley presenting

Don Towsley holds a B.A. in Physics (1971) and a Ph.D. in Computer Science (1975) from University of Texas. From 1976 to 1985 he was a member of the faculty of the Department of Electrical and Computer Engineering at the University of Massachusetts, Amherst. He is currently a Distinguished Professor at the University of Massachusetts in the Department of Computer Science. He has held visiting positions at IBM T.J. Watson Research Center, Yorktown Heights, NY (1982–1983); Laboratoire MASI, Paris, France (1989–1990); INRIA, Sophia-Antipolis, France (1996); and AT&T Labs — Research, Florham Park, NJ (1997). His research interests include networks and performance evaluation. He currently serves on the Editorial board of the Journal of the ACM, and has previously served on several editorial boards including those of the IEEE Transactions on Communications and IEEE/ACM Transactions on Networking. He was a Program Co-chair of the joint ACM SIGMETRICS and PERFORMANCE '92 conference and the Performance 2002 conference. He is a member of ACM and ORSA, and Chair of IFIP Working Group 7.3. He has received the 1998 IEEE Communications Society William Bennett Paper Award and three best conference paper awards from ACM SIGMETRICS. Last, he has been elected Fellow of both the ACM and IEEE.

Towsley reception