TCP Congestion Controls: Algorithms and Optimization Models
CS & EE Depts
California Institute of Technology, Pasadena
Congestion control is a set of distributed algorithms to share
network resources among competing users. They adapt to fluctuations
in the capacity of, and the demand for, these resources.
A TCP congestion control scheme consists of two subalgorithms:
a queue management algorithm (e.g., DropTail, RED, REM etc)
that provides congestion information to sources, and a source
algorithm (e.g., Tahoe, Reno, NewReno, SACK, Vegas, etc) that adjusts
window size in response.
In this tutorial, we will first briefly describe major TCP congestion
control algorithms. Then we will
explain several recently developed optimization models of these
algorithms and use these models to understand, and predict
network performance, such as stability, window dynamics, and
fairness. We will focus on a duality model that treats source rates
as primal variables, congestion measures as dual variables, and
the process of congestion control as carrying out a primal-dual
algorithm to maximize aggregate source utility subject to capacity
constraints. We will illustrate how the duality model provides a
unified framework to model and enhance various TCP congestion
Who should attend?
Researchers and practitioners who are interested in learning about
various TCP congestion control algorithms and their variants, and
especially recent mathematical models of these algorithms.
Steven Low received his B.S. degree from Cornell University and PhD
from the University of California -- Berkeley in 1992, both in
electrical engineering. He has been a consultant to NEC, CA, in 1991
and was with AT\&T Bell Laboratories, Murray Hill, from 1992 to 1996,
with the University of Melbourne, Australia, from 1996-2000, and is
now an Associate Professor of the CS and EE Departments of Caltech.
He has held visiting academic positions in the US, Hong Kong, and Australia.
He was a co-recipient of the IEEE William R. Bennett Prize Paper Award
in 1997 and the 1996 R&D 100 Award. He is on the editorial board of
IEEE/ACM Transactions on Networking. He has been a guest editor of
the IEEE Journal on Selected Area in Communications, on the program
committee of several conferences. His research interests are in the
control and optimization of communications networks and protocols, and
network security and privacy.