This PerfCounter64 counts Frames Marked Red and Discarded by a QoS Policer in the current bin, i.e. frames that exceeded the policer's excess rate limit and were dropped outright. An admin treats a live rise in red-marked-and-discarded frames as direct evidence of traffic loss happening right now due to policing, distinct from the merely-marked yellow frames. If f3FpQosPolicerStatsFMRD is climbing while a customer complains about packet loss, the admin can confirm the loss is caused by the policer discarding excess traffic rather than by network congestion elsewhere.