Work out interface error rate instantly with clear inputs, formula shown and shareable results.
A healthy Ethernet interface should show essentially zero errors, so any sustained error rate points at a physical problem. CRC errors specifically indicate corruption in transit — a damaged cable, dirty fibre connector, failing transceiver or duplex mismatch. Because TCP retransmits, even a very low error rate can produce noticeable throughput loss on long paths.
Error rate
error rate = error frames / frames received; errors per hour = errors / interval
Effectively zero. Ethernet is specified for a bit error rate of 10^-12 or better, so any counter incrementing steadily indicates a fault rather than normal behaviour.
Corruption between the sender's checksum and your receipt: cabling, connectors, optics or electrical interference. Input errors without CRC failures more often mean buffer overruns.