On a congested egress interface WRED is enabled for AF classes with three drop precedences. Which behavior is accurate for WRED operation in this scenario?

Weighted Random Early Detection (WRED) is a congestion avoidance mechanism that proactively drops packets before a queue is full. For AF (Assured Forwarding) classes with multiple drop precedences, WRED is configured to drop higher-precedence packets with a greater probability. This is achieved by setting lower minimum thresholds for higher-precedence packets, causing them to enter the random drop phase sooner. This ensures that during congestion, lower-precedence traffic is discarded first, protecting higher-precedence traffic. The other options are incorrect: WRED is an early detection mechanism, not just tail-drop. It considers average queue length. WRED explicitly uses drop precedence to differentiate drop probabilities. While WRED can mark packets (e.g., ECN), its primary function is to drop packets to signal congestion and prevent queue overflow.