A RED variation for delay control

We evaluate a variation of random early detection (RED) for IP gateways (G/Ws), which drops/marks packets by controlling the average queue delay than the average queue size. The new algorithm is applied when the bandwidth of the outgoing connection varies over time and the service rate is explicitly advertised to the boundary G/W, such as in the available bit rate (ABR) transfer capability. The mechanism embodies the features of RED for congestion avoidance, and additionally guarantees the required queue delay commitments. The mechanism is proposed as complementary to RED, for delay sensitive traffic classes. Performance results using the OPNET simulation package proven that the mechanism is adaptive to changes in the backbone available bandwidth and offers the target QoS in terms of delay