Unifi AP - U6+ - device connecting and disconnecting constantly

Networking & Firewalls
1

Just set up the Unifi Network app at the home of a relative to help them diagnose some wifi issues.

There are two Unifi APs, one UAP-AC-LR, and one more modern U6+. Both are on their latest firmware. Network app is v9.2x

On just the U6+ AP I am seeing a particular device - an iPhone (with WiFi v5) less than 4 months old - regularly connecting and disconnecting, sometimes several times in just a minute or so. There are also “roaming decisions” being logged as device goes from AP to AP but those seem reasonable. Paradoxically it is the more recent AP with the issue, not the older one.

One earlier post #11387 [Unify Log - Unknown device connection and disconnection repeatedly] described similar connection/disconnection problems from a few years back.

I read on a Unifi forum post that this problem could be addressed by checking the “Minimum RSSI” flag and setting an appropriate dB value. Tho that does feel a bit like “disconnecting the wire to the alarm bell” so to speak.

Any insights or wisdom?

2

If the WiFi is on the edge of the range then setting the Minimum RSSI will stop it from connecting then.

3

You might just need to tune the WiFi. Do not choose auto for anything. Make sure both APs are on different channels. On 2.4GHz only use channels 1, 6, or 11 with a bandwidth of 20. On 5GHz, put one AP in the lower bands (channel 44) and the other AP on the upper bands (channel 155). Start the 5GHz with a channel width of 40 and IF they are doing well then try raising the bandwidth to 80. As far as power, choose custom and start the 5GHz at 18dB and the 2.4GHz at about 10dB or lower. Adjust if you are short on range. Keep at least a 7dB difference between 5GHz and 2.4GHz to help with bandsteering. See how that performs. I avoid using minimum RSSI…try tuning first.

4

Thanks. That partic problem seems to have settled down on its own.

Getting the Unifi Network App operational took a bit of time, but definitely worth it in terms of being able to help the customer get consistent and decent wifi.

One resolution with a somewhat satisfying diagnosis of a problem. One user was complaining about the wifi - and quick check of the logs showed one their laptop as having a very mixed experience, while other devices ran just fine. I saw that at a particular time the laptop suddently started getting “Excellent” rather than “Poor” - so i asked what happened at that time. He told me he shut the lid and went out to football.
So with many Apple laptops having wifi antennas in the lid - one suspects a loose or damaged cable running via the hinge mech!