Although they are not queuing methods per se, Random Early Detection (RED) and Weighted Random Early Detection (WRED) are important queue management techniques. RED and WRED work by randomly discarding packets from a queue. RED takes advantage of the congestion control mechanism of TCP. By randomly dropping packets prior to periods of high congestion, RED causes the packet source to decrease its transmission rate. Assuming that the packet source is using TCP, it will decrease its transmission rate until all the packets reach their destination, which indicates that the congestion is cleared. Some implementations of RED, called Weighted Random Early Detection (WRED), combines the capabilities of the RED algorithm with IP Precedence. This combination provides for preferential traffic handling for higher-priority packets. RED/WRED can selectively discard lower-priority traffic when the interface begins to get congested and provide differentiated performance characteristics for different classes of service.

RED and WRED are useful tools for managing data traffic but should not be used for voice. Because IP telephony traffic runs over UDP, IP telephony protocols do not retransmit lost packets, and IP telephony transmits at a constant rate. The IP telephony queue should never be configured for WRED. WRED only adds unnecessary packet loss and reduces voice quality.