A Geek With Guns

Chronicling the depravities of the State.

Error Indicators of Limited Value

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When I moved into this house, I decided to use UniFi gear for my entire network because I wanted to centrally manage it (I, like most people who work in the technology field, am lazy by nature). This house doesn’t have Ethernet running through the walls so I (again, being lazy) opted to rely on a mesh network for most of my networking needs. My mesh network consists of three UAP-AC-M access points.

Like most other people working in the technology field, I’ve been working from home since COVID-19 started making headlines. This means my in-person meetings have mostly been done via remote video conferences. My setup ran smoothly until a few weeks ago when I started experiencing a strange issue where I’d periodically lose my video conference feeds for 10 to 30 seconds. Since I first setup my mesh network my UniFi Controller has reported a large number (as in several hundred per 24-hour period) of DHCP Timeout errors along with a handful of WPA Authentication Timeout errors. It also reported long access point association times for my two mesh nodes (the other node is wired to my switch). Searching Ubiquiti’s online support forum returned a lot of results for individuals experiencing these errors without any resolution. In fact several comments made by Ubiquiti employees stated that the DHCP Timeout errors can be ignored so long as the network is performing well. I ended up ignoring the errors because at the time my network was performing well and nobody seemed to have a resolution to the errors.

I began looking into the problem again when the video conferencing problems I mentioned started to manifest. To make a long story short, I finally figured out my problem. UAP-AC-M access points use the 5Ghz spectrum for mesh communications so they all operate on the same 5Ghz channel, but it’s expected that they utilize different 2.4Ghz channels. My mesh nodes were setup to automatically select their 2.4Ghz and 5Ghz channels during boot up. I assumed this was safe because I boot them up in stages one after the other. That should have caused them to see each other when they booted up and select a different 2.4Ghz channel. According to my UniFi controller, all three 2.4Ghz channels (one, six, and 11 are the only channels that don’t overlap with other channels) were being utilized so I assumed the access points were operating as I expected. After trying to few different settings I decided to manually select the 2.4Ghz channels for my access points. I put one access point on channel one, one on channel six, and one on channel 11.

Since doing that I haven’t experienced any video conferencing problems. Moreover, my DHCP Timeout errors have dropped to almost nothing (I now experience between two and four per 24-hour period), the WPA Authentication Timeout errors have remained at one or two per 24-hour period, and I no longer see any errors about access points taking longer than expected to associate.

If you’re one of the many people experiencing a massive number of DHCP Timeout errors with UniFi access points and you haven’t already manually selected non-overlapping 2.4Ghz channels for your access points, give it a try. I will note that since I live in the country and there are no other visible Wi-Fi networks anywhere on my property, your experience may differ if you’re in an environment with a lot of competing Wi-Fi networks.

Written by Christopher Burg

August 3rd, 2020 at 6:00 am

Posted in Technology

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