This counts packets that this specific QoS queue has discarded rather than transmitted. Because it's queue-specific, it isolates which QoS rule is actually shedding load, which matters when only a low-priority class of traffic, such as bulk file transfer, should be dropping packets under congestion while voice or other priority queues should not. For example, seeing this counter climb only on the queue tied to priority8 (lowest) while priority1's queue stays at zero confirms the QoS scheme is protecting high-priority traffic as designed.