A link keeps flapping and showing physical errors. What do you do first?
Why B is the answer
Inspect and reseat or replace the cable and transceiver
Physical layer errors are usually cable, optic or connector faults.
In detail
- Physical errors call for a physical check first.
- Start with the physical layer.
Use case
An illustrative scenario, not a real incident.
A link flaps with physical errors, and replacing one transceiver stops it.
See it in different ways
flowchart LR A["Is it connected to the right port?"] --> B["Compare with the cabling map"] C["Is the signal good?"] --> D["Check link errors"]
mindmap
root((Links))
Short
Direct attach copper
Long
Optical transceivers
Layout
Rail-optimized
Proof
Cabling map
Error countersflowchart LR S0["Inspect"] --> S1["Reseat"] --> S2["Replace"] --> S3["Watch counters"]
Key point: Physical errors usually mean cable or optic faults.
Why the other options are wrong
- A. Lower the link speed in the training configuration
- That hides the fault.
- C. Update the training code to retry failed transfers
- Retries hide a bad link.
- D. Reinstall the OS on both connected nodes
- The OS is not the problem.