This read-only counter tallies frames the BUS has forwarded that were unicast data frames, including all control frames, meaning they were flooded from the client because the destination wasn't yet resolved. Despite being called unicast, these are frames the BUS is flooding on behalf of a client that doesn't yet know the destination's real ATM address, so a persistently high rate here, rather than a brief burst during address resolution, suggests LEC clients aren't successfully caching direct data-VC information and are repeatedly falling back to flooding through the BUS. A client that never establishes a direct data VC to a frequent destination would keep flooding every frame to that destination through the BUS, showing up as a sustained elevated rate here instead of a brief spike.