Fixed Frequent UniFi Wireless Disconnects

My network is based on Ubiquiti’s Unifi platform. I’m on my second generation of the equipment and have been very satisfied with it overall. Normally it just does its job and disappears into the background. So you can imagine my frustration when multiple devices started randomly flapping. My Oculus Quest would disconnect and reconnect mid-game. My wife’s iPad and kids laptops did the same.

Nailing down the cause was troublesome. I couldn’t find a pattern or common denominator to drill in on. No changes coincided with the onset and all the software and firmware were up to date. The event logs on the controller and devices recorded the disconnects but didn’t show a reason.

I spent a few hours working through Ubiquiti’s excellent support material. Specifically this document https://help.ui.com/hc/en-us/articles/221029967-UniFi-Troubleshooting-Connectivity-Issues#intermitten. Unfortunately, it didn’t directly lead to a resolution.

I had installed Wireshark as part of the troubleshooting process and left a capture running while I used my laptop. Eventually the issue occurred and I was able to see in the trace that the RESET packet was coming from the AP that I was connected to. It was intentionally disconnecting my client. Thinking about this logically jogged my memory.

The UniFi system has a load balancing feature that can be used to control the number of clients connected to each access point. I checked and mine was set to five devices. I have more than thirty connected devices at any given time and three radios. The system was disconnecting and attempting to move clients too frequently trying to satisfy the load balancing setting. I bumped the limit up to fifteen devices and haven’t had the problem since. Not only that, but my wireless devices are actually being balanced across the available radios again.

Clients per radio should be a quotient of active devices.

6 Comments

    1. It used to be in the WLAN group (classic) or Wi-Fi Group (beta) settings. In version 6.013 and above they replaced WLAN groups with AP Groups. AP Groups do not have control s for load balancing. I don’t know if this means the feature has been depreciated or if they just haven’t added the control to the UI yet.

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  1. Is there any other helpful advice for this issue?
    I’ve turned off “Uplink Connectivitiy Monitor”
    Turned off “WIFI AI”
    Turned up “Radio Transmit Power”.
    Every AP has his own unique channel with nearly no overlapping bands.

    And still having issues that clients disconnects randomly of the Wi-Fi network!

    Kind regards

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    1. There are a quite a few things you can look at. First, is there any pattern to the clients that disconnect? Are they always on the same AP, or do they all have the same WiFi adapter, in short is there a pattern? Second, many engineers make the mistake of assuming disconnect issues are caused by the network instead of the clients themselves. If they are Windows devices you can look in the Event Viewer in the System and Application logs for information as well as the WLAN AutoConfig log (Event Viewer ->Applications and Settings -> Microsoft -> Windows -> WLAN Auto-Config -> Operational). I always also suggest installing WireShark on a problematic device and running a capture until the disconnect happens.
      As for the Unifi system itself check in Alerts to see if your WAPs are being disabled due to Radar Detection on DFS channels. Some of the 5Ghz spectrum is shared with radar channels, by law if the WAP detects interference on DFS channels if has to shutdown for a minimum of 30 minutes. If it isn’t that I would start digging though the WAP and controller logs for more info see https://help.ui.com/hc/en-us/articles/204959834-UniFi-How-to-View-Log-Files . Good luck.

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