Applying delay random early detection to IP gateways

The Random Early Detection (RED) algorithm controls the average queue size of Internet Protocol (IP) gateways by marking packets. Although RED provide s efficient congestion avoidance, it cannot provide queuing delay control w hen the output bandwidth varies over time. In this paper, we introduce Dela y RED (DRED), a variation of RED, which marks packets by monitoring the ave rage queue delay. The mechanism embodies all the features of RED and additi onally controls the average queue delay, even when the output service rate varies over time., such as with the Available Bit Rate (ABR) transfer capab ility. DRED is proposed as a complementary mechanism to RED and can be used for congestion avoidance and for applications requiring a better Quality o f Service (QoS) in terms of delay. The performance of DRED has been verifie d on the OPNET simulation package. DRED proved to be adaptive to the ABR ba ndwidth fluctuations and offers the target QoS in terms of average delay. ( C) 2001 Elsevier Science B.V. All rights reserved.