A read-only counter of frames received on this interface that carried an unknown DLCI value. A rising count here suggests either a misconfigured remote device sending to the wrong DLCI or a provisioning mismatch between the two ends of a circuit, prompting an admin to check DLCI configuration on both sides. If cmFrDlcmiRcvUnknownDLCI starts climbing right after a provider changes circuit provisioning, the admin would check whether the DLCI numbers on both ends still match.