Joint CS/ECE Seminar
Date: Thursday, 10/10, 4pm
Location:   Tech M345 with reception in L324

TITLE:   Separating wheat from chaff:
         On Internet modeling and model validation

SPEAKER: Walter Willinger
         AT&T Labs-Research
         Florham Park NJ 07932
         Email: walter@research.att.com

ABSTRACT:

Recent empirical discoveries concerning various scaling properties of
the temporal dynamics of Internet traffic or of some of the topological
features associated with the physical structure of the Internet have
resulted in a number of proposed models or ``explanations'' of these
``emergent'' phenomena.  Many of these explanations invoke concepts
such as fractals, chaos, or self-organized criticality, mainly because
these concepts are closely associated with scale-invariant phenomena
and power laws.  In this talk, I will discuss a simple framework for
Internet model validation; that is, identifying those explanations/models
that go beyond data fitting, are relevant for the networking application
at hand, and can provide a basis for developing a useful, consistent,
and verifiable theory of large-scale TCP/IP networks.  In particular,
I will discuss why some recently proposed criticality-based models
or ``explanations'' from statistical mechanics are spicious, at
least as far as the networking context is concerned.  (This is joint
work with R. Govindan, S. Jamin, V. Paxson, and S. Shenker,
Proc. Nat. Acad. Sci. US, Vol. 99, suppl. 1, pp. 2573-2580, 2002.)

SHORT BIO:

Walter Willinger received the Diplom (Dipl. Math.) from the ETH Zurich,
Switzerland, and the M.S. and Ph.D. degrees from the School of Operations
Research and Industrial Engineering, Cornell University, Ithaca, NY.
He is currently a member of the Information and Software Systems Research
Center at AT&T Labs-Research, Florham Park, NJ. Before that, he was a Member
of
Technical Staff at Bellcore (1986-1996). He has been a leader of the work
on the self-similar (``fractal'') nature of data network traffic
and is co-recipient of the 1996 IEEE W.R.G. Baker Prize Award and the
1994 W.R. Bennett Prize Paper Award from the IEEE Communications Society
for the paper titled "On the Self-Similar Nature of Ethernet Traffic".

Host:
Dr. Peter A. Dinda
Assistant Professor
Department of Computer Science
Northwestern University
1890 Maple Avenue
Evanston, IL 60201
http://www.cs.northwestern.edu/~pdinda
pdinda@cs.northwestern.edu