Exactly as described, this is a running total of received packets on this benchmark port that failed CRC validation. Unlike the transmit-side CRC error counter which implicates the local device, CRC errors on receive point to corruption introduced somewhere between the remote sender and this specific port -- bad cabling, a failing SFP, EMI, or a marginal patch panel connection -- making this the counter to watch first when a test shows unexplained frame loss. For example, CRC errors climbing in exact proportion to reported frame loss on a throughput test would confirm physical-layer corruption, not congestion, as the actual cause of the failing test.