What it means
A link negotiates a supported speed between its two ends. The connection may be slower than the port's advertised maximum if cabling, an adapter or the other port limits it. Wired connections usually avoid Wi-Fi interference, but still share upstream capacity and depend on switches, routing and servers.
How this affects everyday use
Damaged pairs, loose connectors, an unsuitable cable run or a limited USB adapter can cause reduced speed or intermittent disconnections. Link lights alone do not prove error-free operation.
A practical example
A gigabit-capable computer links at a lower rate because one cable pair is damaged.
What to check
- Inspect negotiated speed at both ends where available.
- Check error counters and correlate them with disconnections.
- Compare a known-good cable and port without changing unrelated settings.
Practical next steps
- Replace confirmed faulty patch leads.
- Have permanent cabling tested if the fault follows the run.
- Use adapters and switches matching the required link capability.
Keeping it reliable
Label cables and avoid tight bends or crushed runs. Use suitable installation components. Fibre handling and building cabling require appropriate expertise; never look into an optical connector.