Weighted random early detection

Weighted random early detection (WRED) is a queue management algorithm with congestion avoidance capabilities. It is an extension to random early detection (RED) where a single queue may have several different queue thresholds. Each queue threshold is associated to a particular traffic class.

For example, a queue may have lower thresholds for lower priority packet. A queue buildup will cause the lower priority packets to be dropped, hence protecting the higher priority packets in the same queue. In this way quality of service prioritization is made possible for important packets from a pool of packets using the same buffer.