This counter counts frames received when no channel had been set up to accept them, meaning the frames arrived for a connection that does not exist on the switch. A nonzero value alerts an administrator to a provisioning mismatch, such as the far end sending traffic on a DLCI that was never configured locally. For example, an engineer troubleshooting a new circuit that isn't passing traffic would check this counter to see if inbound frames are arriving but being discarded for lack of a matching channel.