This is the native 64-bit counter of CLP=1 cells in the ingress direction of this channel discarded at the class-of-service queue due to overflow. Since CLP=1 cells are the ones intended to be shed first under congestion, a growing value here reflects normal congestion management rather than a fault, and an admin would expect it to track with overall ingress load. Sustained growth during off-peak hours, however, would suggest the CoS queue is undersized for the channel's committed CLP1 traffic even at low utilization.