Analysis of a Rate -based Control Policy with Delayed Feedback and Variable Bandwidth Availability

The investigation of feedback c o n trols for telecommunication networks has recently gained considerable interest. The reason is the deenition of a new ATM service category, the so-called Available Bit Rate service, whose primary goal is the economical support of applications with vague requirements for throughputs and delays. One class of possible feedback controls is formed by the rate-based mechanisms. Feedback from the network switches to the end systems gives users the information necessary to appropriately adjust their transmission rates. This type of control has beeninvestigated to some extent in the existing literature, assuming a constant transmission rate on a bottleneck link. In this paper, we present a discrete-time analysis of a feedback control policy, taking into account a bottleneck link capacity t h a t v aries according to a general probability distribution. The control policy we look at belongs to the class of explicit rate control mechanisms considered for the Available Bit Rate service. We compute the buuer content and transmission rate distributions at appropriate time instants to investigate the innuence of the variation of the bottleneck link capacity on the system performance.