This read-only counter, in cells, tracks the number of valid CLP=0 cells in the egress direction of this channel discarded at the class-of-service queue due to overflow. An admin treats any nonzero value here as a serious signal, since high-priority cells should rarely be dropped even under CoS queue congestion, unlike their lower-priority counterparts. For example, if this counter increments on an egress channel carrying voice traffic, the admin should escalate quickly since it indicates even protected traffic is now being lost on the way out to the destination.