CBW240AC older devices lose connectivity randomly

[netwteam]

Hello,

We have 3x CBW240AC access points covering about 1000 sqft with about 15-20 devices simultaneously connected (mostly Apple devices). 4 SSIDs are broadcast, including a Guest network and 3 different VLANs for different usages (contractor / staff / technical devices). For compatibility with older devices, both WPA2 and WPA3 are enabled on all SSIDs.

On the staff SSID on which we have most of our devices connected, I noticed that the most recent devices work perfectly well (no service interruption, stable connection and good bandwidth) but devices older than 2 years tend to lose connectivity (regardless of their location in the office), trying to reset the connection but often failing to reset it automatically (until manually reset by switching WiFi off and on again on the device itself; sometimes a reboot is even necessary).

I noticed that behavior on different types of devices: MacBook, MacBook Air, iPad and even iPhone.

Does someone have any idea of the root cause and how we could solve it? As it's quite annoying especially while videoconferencing.

Thanks for your help!

Allan

P.S. : macOS, iOS, the APs firmware are all up-to-date to the latest version available.

[CoreyP319]

Thank you for sharing details about the issue you're encountering. I wasn't able to locate any bugs submitted for CBW and Apple devices. I'll circulate your situation with the team to see if there is a known approach. Meanwhile, submitting a case to TAC should help, which is covered with your purchase.

[Martin Aleksandrov]

Hi netwteam,

Few questions.

So you are running firmware version 10.4.1.0 on the CBWs?

What is the type of deployment - non-mesh deployment or mesh deployment?

Can you try to use WPA2 only on all SSIDs just for the test?

Is that behaviour seen on non-mac/iPhone/iPad devices as well?

Thanks,

Martin

[netwteam]

Hello and thank you for your time and efforts on this issue!

@CoreyP319: I tried to create a dedicated SSID with only WPA2 enabled for older devices only but activity is light these days. I'll resume testing later this week.

@Martin Aleksandrov:

- Indeed, 10.4.1.0 on all 3 APs (with 10.3.1.1 as backup image).

- It's mesh deployment as there were plans to extend to a non-wired area but it's never been done: maybe I could disable mesh in settings and see if it helps.

- As explained above, I tried dedicating a WPA2-only SSID for older devices and I'm looking for a bit more traffic later this week to see if it solves the issue. If not, I'll try switching all SSIDs to WPA2-only for a couple of days.

- I didn't notice similar behavior with non-Apple devices but it's hard to tell as it's essentially guest users (on the guest SSID) who have non-Apple devices (and in the current context, we have very few visitors...)

Thanks again,

Allan

[Martin Aleksandrov]

Hi, netwteam,

Thank you for sharing the details.

Please disable WPA3 on suspected SSID and leave only WPA2 as a security access method. Then monitor for legacy end clients behaviour. If the issue happens only with WPA2/WPA3 and/or WPA3 modes enabled and mostly to MacBook, MacBook Air, iPad and iPhone devices then make sure they do support WPA3. It seems more like end device incompatibility with the WPA3 standard.

Regards,

Martin

[netwteam]

Hello,

Quick update on the issue. After further investigation, I noticed that two APs out of the three APs on our site were restarting about every 15-20 minutes in high demand times (when most users were connected). I tried switching from mesh to traditional deployment and it solved that problem.

Since that time, we no longer notice persistent disconnections even from older Apple devices. Only, sometimes, the connection has to "restart" (i.e. loss of connectivity with the AP, the device searches networks and it automatically reconnects to the same AP with same SSID within a few seconds).

I'll try to get more detailed statistics as to how often this happens and I also plan on checking if it's on the same devices as before (I've got the feeling that fewer devices are impacted than before switching to traditional deployment).

Have a great weekend!

Allan

[CoreyP319]

Hey Allan,

I couldn't find anything describing your particular issue in the doc. You should reach out to TAC for assistance with the restarting APs. Meanwhile, there is a method to pull the tech support bundles for specific APs:

•Each access point/mesh extender, including the primary AP, has a tech support bundle specific to access point functionality.

•To access it, go to Monitoring > Access Points, click on an access point, and click the “Start” button on the “Tech Support” line. This generates the bundle. When it’s done and the “Download” button has become available, click it.

Those logs may reveal the cause of the restarts. Keep us posted!

[CoreyP319]

Hey Allan,

Thanks for the extra details. Losing Mesh functionality is no good. I'm sorry you're dealing with that right now. We had a roundup on CBW this past week and there was a great internal document about the ins and outs of CBW. Your situation isn't ringing any bells for me but I'll check again on Monday. Send those stats our way and we'll take a look at that from our end.

Have a great weekend yourself!