This counter tracks the total number of cells received with Cell Loss Priority set to 0, the higher-priority cells that the network tries hardest not to discard during congestion, on this logical interface. It's a baseline traffic figure that, combined with bbIfRcvClp0DiscCells, lets an admin calculate what fraction of high-priority ingress traffic is being dropped. A high discard rate relative to bbIfRcvClp0Cells would indicate the interface is congested even for its most protected traffic.