This PerfCounter64 counter reports a count of Layer 2 control-protocol frames that were processed rather than discarded, in the downstream (network-to-subscriber) direction, tallied over the most recent completed bin. An admin reads it as one line item in the port's or flow's traffic composition, useful for confirming a particular kind of traffic (broadcast, multicast, unicast, or protocol-processed frames) is behaving as expected for that direction. A value of roughly 33622 for cmEthernetNetPortHistoryL2CPFP on network (uplink) port 42 during the interval only becomes meaningful next to the port's total frame count; taken alone it tells an operator this specific traffic category is present and roughly how large a share it represents.