Direct answer
A complete failure should be separated into power or eligibility, the external path, and the component itself before any reset. For gigabit Ethernet link speed, first inspect negotiated speed and connect a known Cat5e+ cable directly between known gigabit ports.
What this covers
- gigabit Ethernet link speed with this exact failure state
- Diagnosis across device capability versus cable pairs, wall jack, switch and power saving
- Customer-accessible observation, settings and external components
What it does not cover
- ×A displayed manufacturer error code with a different documented meaning
- ×Live electrical, sealed-system, internal battery-cell or gas repair
- ×A claim that every model exposes identical controls
Capture the exact failure state
ReversibleRecord whether the feature is absent, disabled, powered but unresponsive, or showing a message. Expected behavior: negotiate 1000 Mbps or higher through every cable pair and port.
Isolate the component boundary
ReversibleInspect negotiated speed and connect a known Cat5e+ cable directly between known gigabit ports. Test the simplest supported configuration with unrelated accessories and optional services removed. Boundary to separate: device capability versus cable pairs, wall jack, switch and power saving.
Correct only the proven cause
ReversibleReplace the segment or port that falls to 100 Mbps. Restore only the failed prerequisite or path; do not change working layers.
Verify and stop safely
ReversibleRepeat from a cold start and complete one normal use. Stop for wet, pinched, hot or visibly damaged cabling/equipment.
Evidence ledger
Sources behind this answer
Visible sources support the visible claims. Home Product Support records the publisher, the fact used and the review date; community reports can suggest an issue but do not become a published fact on their own.
Exact questions
Common follow-ups
What should I check first when gigabit Ethernet link speed has this problem?+
Inspect negotiated speed and connect a known Cat5e+ cable directly between known gigabit ports.
Why not factory-reset immediately?+
The useful boundary is device capability versus cable pairs, wall jack, switch and power saving. A reset can erase state without proving which side failed.
When should I stop troubleshooting?+
stop for wet, pinched, hot or visibly damaged cabling/equipment.
Answer for the exact device and software version shown above.