Selfish Routing and the Price of Anarchy
240 pp., 7 x 9 in,
- Published: May 6, 2005
An analysis of the loss in performance caused by selfish, uncoordinated behavior in networks.
Most of us prefer to commute by the shortest route available, without taking into account the traffic congestion that we cause for others. Many networks, including computer networks, suffer from some type of this "selfish routing." In Selfish Routing and the Price of Anarchy, Tim Roughgarden studies the loss of social welfare caused by selfish, uncoordinated behavior in networks. He quantifies the price of anarchy—the worst-possible loss of social welfare from selfish routing—and also discusses several methods for improving the price of anarchy with centralized control.
Roughgarden begins with a relatively nontechnical introduction to selfish routing, describing two important examples that motivate the problems that follow. The first, Pigou's Example, demonstrates that selfish behavior need not generate a socially optimal outcome. The second, the counterintiuitve Braess's Paradox, shows that network improvements can degrade network performance. He then develops techniques for quantifying the price of anarchy (with Pigou's Example playing a central role). Next, he analyzes Braess's Paradox and the computational complexity of detecting it algorithmically, and he describes Stackelberg routing, which improves the price of anarchy using a modest degree of central control. Finally, he defines several open problems that may inspire further research. Roughgarden's work will be of interest not only to researchers and graduate students in theoretical computer science and optimization but also to other computer scientists, as well as to economists, electrical engineers, and mathematicians.
Distributed competitive decision making, as opposed to centralized planning, is emerging as the norm in modern systems such as the Internet. The exciting area of algorithmic game theory, which combines methodology from two rich fields, attempts to identify and understand new issues arising as a consequence of this fact. This book provides a vivid glimpse into this area by dealing comprehensively with one of its well-studied problems.
Vijay V. Vazirani, College of Computing, Georgia Institute of Technology
Recent trends in the analysis and design of computer networks take into account rationally selfish behavior by the network's different components. This book introduces this exciting interdisciplinary type of analysis and presents some of its clearest and most influential applications.
Noam Nisan, School of Computer Science and Engineering, Hebrew University of Jerusalem