What your hardware won't report¶

Some readings simply aren't sent by the hardware or the UniFi controller. Ferrule shows those as a dash (—) or leaves them out. It never fills a gap with a zero, because a zero would look like a real reading: a fanless switch would look like one whose fan had stopped.

This page lists the gaps you are most likely to meet, so a blank isn't mistaken for a fault.

Gateway SFP+ ports: no optic readings¶

UniFi gateways often send no temperature, receive power or other optic readings for their SFP+ ports, even with an optic that supports them. The port detail shows dashes and says:

This platform is not reporting module diagnostics for this cage. Gateway SFP+ ports often do not, even with a DDM-capable optic seated.

It's a gap in what the gateway sends, not a problem with your optic. Where a port does send readings, Ferrule shows and alerts on them as in Switches, ports and optics.

Cable modems: no per-channel signal figures¶

The UniFi cable modem doesn't pass its per-channel radio readings to the controller: upstream SNR, transmit power, T3 and T4 timeout counts, codeword errors. Ferrule can't show what it never receives, and the modem tile says so.

What you do get, and what matters most in an ISP complaint: the modem's re-initialisation reason and who it blames, its DOCSIS state, its uptime, and errors on its Ethernet port. See WAN, outages and your ISP.

CRC errors on some switches¶

Many switch models don't report CRC errors separately. The port detail shows a crc line only where the switch sends one. Receive and transmit errors are still counted, and Port errors climbing still works.

The controller's event log¶

The UniFi controller's event log can't be read from outside on current Network releases. So Ferrule keeps its own record of what it sees happen: reboots, firmware changes, devices going offline, link drops, speed changes, Wi-Fi channel changes, modem re-initialisations, speed tests and every alert.

What that means for you:

Ferrule knows only what happened while it was running. It has no record of a firmware update from last month.
The controller keeps outages for about 21 hours. Ferrule copies them every minute and keeps them for a year. An outage that was already older than that when Ferrule first ran is gone.
A change made while Ferrule was stopped is noticed on its first poll and labelled found when the collector started, because its time is when it was noticed. Reboots are the exception: uptime dates them exactly.

Flap counts are a floor¶

Ferrule counts a link drop when a port is up at one poll and down at the next. A port that drops and comes back between two polls isn't seen, so a port's flap count can be lower than the truth, never higher.

Polling has a floor¶

Setting	Default	Lowest allowed
`POLL_INTERVAL`: devices and ports	`30s`	`10s`
`WAN_POLL_INTERVAL`: outages, ISP details and speed tests	`60s`	`30s`
`PROBE_INTERVAL`: the demarcation probe	`60s`	`15s`

Anything lower is raised to the floor. Reading a controller's devices is an expensive request, and polling harder slows the controller for everyone on a larger site. The outage history doesn't change faster than every 30 seconds anyway.

If something's wrong¶

If a reading is blank on a device that should report it, check the same device in the UniFi app first. If it's blank there too, the hardware isn't sending it. If the app shows it and Ferrule doesn't, report it at GitHub issues, with the device's model and firmware.