Active queue management using adaptive RED

Random Early Detection (RED) [1] is an active queue management scheme which has been deployed extensively to reduce packet loss during congestion. Although RED can improve loss rates, its performance depends severely on the tuning of its operating parameters. The idea of adaptively varying RED parameters to suit the network conditions has been investigated in [2], where the maximum packet dropping probability max
p
has been varied. This paper focuses on adaptively varying the queue weight w
q
in conjunction with max
p
to improve the performance. We propose two algorithms viz., w
q
-thresh and w
q
-ewma to adaptively vary w
q
. The performance is measured in terms of the packet loss percentage, link utilization and stability of the instantaneous queue length. We demonstrate that varying w
q
and max
p
together results in an overall improvement in loss percentage and queue stability, while maintaining the same link utilization. We also show that max
p
has a greater influence on loss percentage and queue stability as compared to w
q
, and that varying w
q
has a positive influence on link utilization.