This read-only counter tallies the number of cells discarded on this channel specifically because the ingress queue was completely full, representing outright cell loss from queue overflow rather than selective CLP-based discard. Admins treat any nonzero, growing value here as a clear sign of real, unmitigated congestion loss on the channel, more severe than selective discard mechanisms catching excess traffic beforehand. For example, if chanIngrQfullDiscardCells starts incrementing while the CLP-threshold discard counters stay flat, it suggests the queue depth itself is undersized for the traffic being offered, not just that CLP-tagged traffic is being properly shed.