This counter records the number of Layer 2 control protocol frames discarded at this flow point during the current interval. A rising count tells the admin that L2 control-plane frames, such as STP BPDUs, are being rejected at this specific flow point, which could disrupt spanning-tree or link-aggregation behavior for the traffic passing through it. For example, if a customer's tunneled STP topology becomes unstable, the admin would check whether cmFlowPointStatsL2CPFD on the relevant flow point shows BPDUs being discarded.