This read-only counter, in frames, tallies frames for which this switch itself set the BECN bit, as opposed to relaying an existing marking. It pinpoints this switch as the source of the backward congestion signal being sent to the far-end transmitter, rather than a passthrough of a signal generated further downstream. A burst of tagged BECNs coinciding with a temporary spike in traffic through this switch, on an otherwise steady connection, would confirm this device as the congestion point rather than a downstream link.