This Counter64 tallies frames received at ingress and passed onto the circuit that specifically carry the DE (Discard Eligible) bit set, distinguishing them from the general circuitInFrames total which counts all frames regardless of DE marking. A frame arrives already marked DE when it was tagged non-conforming somewhere upstream (see circuitInFramesTagged), so a rising count here indicates this circuit is continuing to carry traffic that's already been flagged as excess bandwidth elsewhere in the network. For example, if this count grows quickly relative to circuitInFrames, it suggests a meaningful share of this circuit's traffic is already running above its committed rate upstream, at elevated risk of being dropped during any downstream congestion.