This counter records the number of unicast frames sent out of this Ethernet port during the current interval. As the bulk of normal point-to-point traffic, an admin uses this as the primary indicator of typical outbound activity on the port, separate from broadcast or multicast traffic. For example, if cmEthernetTrafficPortStatsESUF drops to near zero while the port remains link-up, the admin would suspect the connected device has stopped sending normal traffic, perhaps due to an application or NIC failure.