Kernaali ToolsIf the actual Ethernet uplink negotiates at 100 Mbps, a fast Wi-Fi PHY rate cannot make traffic across that uplink exceed its capacity. Verify the link at both ends, then inspect the physical path and configured port speed before changing radio channels or replacing the gateway.
Applies to: UniFi Network application with Ethernet-connected UniFi APs, switches or gateways whose exact ports support the intended speed. Current wired-performance and offline-device documentation. This is a copper-link diagnostic path, not an SFP compatibility matrix, a promised speed benchmark or a firmware-fixed claim.
Validation: documentation-checked on . No device or lab test is claimed. Version references identify the documentation checked, not a firmware upgrade recommendation.
Separate three measurements
| Measurement | What it describes | What it cannot prove |
|---|---|---|
| Ethernet negotiated speed / FE or GbE | The current wired link between adjacent ports | End-to-end application throughput |
| Wi-Fi PHY rate | The radio’s link rate to a client | The capacity of the AP’s wired uplink |
| Application or speed-test result | The complete tested path and workload | Which individual hop is the bottleneck |
The official wired-speed guide starts with cabling and negotiated port speeds before resources and software features. Inspect the current port view and, where available, the peer’s own link status. A stale topology label alone is not sufficient reason to interrupt a working link.
Identify the first unexpectedly slow link
Trace the test client through its AP or access switch, each uplink and the gateway WAN. Check the exact port capability on both endpoints and any intermediate injector or adapter; a gigabit-capable AP does not upgrade a 100 Mbps intermediate device.
Compare a local authorized wired transfer with an Internet test. If the local path is fast but the WAN link is slow, focus on the gateway-to-upstream connection. If every client behind one AP is limited while other APs are fine, inspect that AP’s uplink before modifying every SSID. Record any forced speed setting and compare it with the intended configuration.
Change one cable or port at a time
Plan the interruption and save the native/tagged VLAN and PoE settings of the affected port. Reseat the connection once, then compare with a known-good short cable and a compatible known-good port. Include patch leads, wall termination and intermediate hardware in the physical path. The offline-device guide also uses cable/port substitution to isolate faults.
When moving an AP, preserve both management and client VLAN membership. Do not force a higher speed to conceal a damaged physical path. Correct a mistaken manual port-speed setting only after verifying both endpoints’ capabilities, and retain local recovery because changing negotiation can drop the link.
A fault that follows the cable/run differs from one that follows the device or a single switch port. Record that result before purchasing replacement equipment. This guide does not infer that every 100 Mbps link is defective: some endpoints are designed for that speed.
Verify stability and application throughput
Confirm the expected negotiated speed remains stable at both ends, then repeat the same authorized workload. Check for link flaps or errors and ensure the AP still receives the correct management address and clients can use their applications. Do not demand that payload throughput equal the nominal Ethernet or Wi-Fi link rate.
If the link is correct but throughput remains poor, inspect the rest of the path, rate limits and resource load as a separate branch. Do not disable all threat inspection or queues simply to improve a speed-test number.
For rollback, restore the documented port configuration and known-good cabling arrangement. If a cable was verified faulty, leave it out of service rather than reinstalling it to recreate the old layout. Remove temporary test connections and retain a concise private result.
Power loss versus data-link problems · VLANs after a port move · Radio settings after the wired path is verified
Technical references
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