WLC code 8.5.135 - DCA bugged?

[Oscar Olsson]

I was previously running 8.5.131 with FRA and DCA with "best" channel width, using 2700 series AP's. With .131 the DCA selects an 80MHz bandwidth for the 5GHz band on all three AP's. With .135, it reverts back to 20 MHz. To me this seems like a bug. I haven't been find any good matches in the bug database either. What about others running .135, have you seen this too?

[Rasika Nayanajith]

Select 80MHz on all those 3APs seems odd (Unless you only got 3 x 5GHz AP in that environment). In an enterprise environment using 80MHz is nearly impossible.

Do you have clear idea about how 5GHz spectrum looks like in your area ?

I would set to 40MHz instead of "Best"

HTH

Rasika

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[Oscar Olsson]

The question isn't how to work around it. The question is why the behavior differs with a fully working conf in .131 that produces vastly different results in .135 . The environment in question is a lab/home environment.

Anyway, I've now done some experimenting. I downgraded from .135 to .131 and after an hour or two, AP's switch back to 80MHz. Then I upgrade again, AP's switch to 20MHz after an hour or two. Downgrading to .131 makes them switch back to 80MHz.

So there is definitively a behavioral difference between the two releases, where I believe .131 behavior is the expected behavior, when choosing the best channel width - meaning that 80MHz channels is the optimal choice (160MHz is too much) when air quality and utilization of spectrum allows it. I would consider .135 as confirmed bugged, as previous releases behave as .131 .

Ps. 80MHz channels work just fine in larger enterprise environments too these days.

[Oscar Olsson]

UPDATE: After some more testing, it seems like the new behavior is that it resets all AP's to 20MHz channels upon startup. In previous upgrades, the old channels were left as-is until the new code had run through DCA, FRA etc. But once it has done all this, they're set after approx 2 hours with my intervals (DCA = 10 min, FRA = 1 hour). So now it's more like a minor annoyance that might look scary if you're not aware of this. :)

[Oscar Olsson]

UPDATE: It seems to also apply when you reboot your WLC. So this is a more severe issue than I initially thought - meaning it only happens after upgrade.