Is the loop back test effective placed on switch fiber port when trying to determine if CRC errros are due to the faulty port or this is pointless as there is no real traffic?
Switch Port Errors – Troubleshooting CRC Errors
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Is the loop back test effective placed on switch fiber port when trying to determine if CRC errros are due to the faulty port or this is pointless as there is no real traffic?
Best Answer
Assuming this is an Ethernet link a loopback test would be useless unless you could also send some frames over the link. Unlike POS, frames are only sent when there is traffic to send and you won't see CRC errors if you don't have any frames.
There are devices supporting BERT (bit error rate test) so you can put a loopback fibre and run a test to determine if the optical module and framer is working correctly but it's not common on classic Ethernet switches.