Affiliations: College of Computing, Georgia Institute of Technology, Atlanta, GA 30332, USA, Tel: +1 404 853 9376 | Department of Computer Sciences, University of Wisconsin – Madison, Madison, WI 53706, USA
Note: [] This paper is a revised and extended version of a paper presented at the ACM SIGCOMM conference, Zurich, 1991.
Abstract: We present an approximate analysis of a queue with a dynamically changing input rate that is based on implicit or explicit feedback information. This is motivated by proposals for adaptive congestion control algorithms, [6] and [15], where the sender's window size at the transport level is adjusted based on perceived congestion level of a bottleneck node. We develop an analysis methodology for a simplified system; however, it is powerful enough to answer important questions regarding stability, convergence (or oscillations), fairness and the significant effect that delayed feedback plays on performance. This paper quantitatively identifies the cause of the these effects, vis-a-vis the system parameters and properties of the algorithm used. Several conservation laws and balance equations governing this system are given. The model is fairly general and can be applied to evaluate the performance of a wide range of feedback control schemes. It is an extension of the classical Fokker-Planck equation. Because the Fokker-Planck equation models diffusion, it addresses traffic variability, and in a sense, extends earlier fluid approximation analyses.
