INPUT RATE FLOW-CONTROL FOR HIGH-SPEED COMMUNICATIONS NETWORKS USING BURST LEVEL FEEDBACK-CONTROL

We propose a new input rate flow control scheme wherein the credit inc rement rate is updated periodically as the loading status varies. Base d upon the observed status of each station's burst-level activity, the network access node distributes feedback control signaling messages t o the stations. These signaling messages allow the stations to adapt t heir credit increment rates in accordance with system burst-loading co nditions. The Generic Flow Control (GFC) field of the ATM cell header can be used to carry information characterizing the burst-level loadin g 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 invol ves a network switch (such as a fast packet switch in high-speed metro politan or wide area networks) and a number of regulated source statio ns which drive the network switch. To avoid packet retransmissions due to cell losses at the access switch, each user station (or CPN) imple ments locally a replica of the input regulation scheme. The output tra ffic streams from the source stations, as regulated by the local input rate control mechanism (and adapted by the status messages), load a p acket switch which is modeled as a multiple-server queueing system. Pe rformance curves are presented to illustrate the statistical queue-siz e behavior and message delays at both the source stations and the netw ork switch.