This read-only counter, in cells, tracks the number of valid RM cells in the egress direction of this channel discarded at the class-of-service queue due to overflow. An admin cares because losing outbound RM cells undermines the ABR feedback loop for the peer endpoint, potentially causing that end's rate-control algorithm to behave incorrectly due to missing information. For example, if a remote ABR endpoint behaves erratically, the admin checking this local egress discard counter might discover this switch itself is dropping the feedback cells meant to reach that peer.