This field is the average, as frozen at the moment this historical snapshot was taken, of the per-interval delta values for FCoE frames the adapter attempted to send but discarded instead of transmitting, taken across the retained collection history for this stats object. Admins watch this to separate a genuinely sustained problem from one noisy interval — if DeltaAvg for droppedTx on this interface is climbing, this usually tracks a congested or paused fabric-facing uplink, rather than a one-off spike. For example, an average of 4 frames per interval sustained over many polling cycles points at a chronic issue rather than a one-time glitch.