Alignment errors are a count of the number of frames received that don't end with an even number of octets and have a bad CRC.
FCS error count is the number of frames that were transmitted/received with a bad checksum (CRC value) in the Ethernet frame. These frames are dropped and not propagated onto other ports.
When operating at half-duplex setting, some data link errors such as Frame Check Sequence (FCS), alignment, runts, and collisions are normal. Generally, a one percent ratio of errors to total traffic is acceptable for half-duplex connections. If the ratio of errors to input packets is greater than two or three percent, performance degradation may be noticed.
When operating at full-duplex, FCS, Cyclic Redundancy Checks (CRC), alignment errors, and runt counters should be minimal. If the link is operating at full-duplex, the collision counter is not active. If the FCS, CRC, alignment, or runt counters are incrementing, check for a duplex mismatch. Duplex mismatch is a situation where the switch is operating at full-duplex and the connected device is operating at half-duplex, or vice versa. The result of a duplex mismatch will be extremely slow performance, intermittent connectivity, and loss of connection. Take note that using "autonegotiation" on both ends may cause a problem between different vendor equipment due to the proprietary additions to the protocol that some vendors implement. Try hard-coding both ends for speed and duplex settings.
Other possible causes of data link errors at full-duplex are bad cables, faulty switch port, or NIC software/hardware issues.
Hi everyone, I would like to thank you in advance for any help you can provide a newcomer like myself!
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