Algorithms for congestion detection and control

Abstract

This paper proposes Early Congestion Detection and Control (ECDC) gateways for congestion avoidance which detects early congestion by computing the average queue size and can notify connections of congestion either by dropping packets or by setting a bit in packet headers. When the average queue size exceeds a preset threshold, the gateway drops or marks each arriving packet with a certain probability which is a function of the average queue size. ECDC gateways keep the average queue size low while allowing occasional bursts of packets in the queue. During congestion, the probability that the gateway notifies a particular connection to reduce its window is roughly proportional to that connection's share of the bandwidth through the gateway. © Springer-Verlag 2004.