Input rate flow control for high speed communications networks using burst level feedback control

Abstract

AbstractWe propose a new input rate flow control scheme wherein the credit increment rate is updated periodically as the loading status varies. Based upon the observed status of each station's burst‐level activity, the network access node distributes feedback control signaling messages to the stations. These signaling messages allow the stations to adapt their credit increment rates in accordance with system burst‐loading conditions. The Generic Flow Control (GFC) field of the ATM cell header can be used to carry information characterizing the burst‐level loading activity at the switch used in the proposed scheme. We also present queueing models to study the system performance at the network access points. For this purpose, we select a sub‐network topology which involves a network switch (such as a fast packet switch in high‐speed metropolitan or wide area networks) and a number of regulated source stations which drive the network switch. To avoid packet retransmissions due to cell losses at the access switch, each user station (or CPN) implements locally a replica of the input regulation scheme. The output traffic streams from the source stations, as regulated by the local input rate control mechanism (and adapted by the status messages), load a packet switch which is modeled as a multiple‐server queueing system. Performance curves are presented to illustrate the statistical queue‐size behavior and message delays at both the source stations and the network switch.