This 16-bit counter tracks cyclical redundancy check failures on this port since the last reset, which the description attributes specifically to line noise. Because CRC failures are a physical-layer signal-quality indicator distinct from the CPU-driven overrun/underrun errors, a climbing CRC count is the specific evidence an admin needs to justify escalating a noisy circuit to the carrier or checking cabling. For example, a steadily increasing CRC error count on one port while its neighbors stay at zero strongly suggests a bad cable or connector on that specific circuit rather than a device-wide issue.