This PerfCounter64 counter reports multicast Frames sent in the A2N 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 16327 for cmEthernetNetPortHistoryESMF on network (uplink) port 9 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.