RRM not assigning 40Mhz channels automatically

[aflbakker]

HI,

In the past with 8.2 code I was running into CSCve24687 (https://quickview.cloudapps.cisco.com/quickview/bug/CSCve24687). In our case this meant a lot of AP's on channel 36 power level 1 (I'm focusing on 5Ghz for now).

In the meanwhile we are running 8.5.151.0 but I see that the issue remains (meaning AP's that had issues with 8.2 are displaying same channel assignments with 8.5). I tried the global restart for both 2,4 and 5Ghz but no luck. It looks like AP's that are newly installed with 8.5 are not suffering from this issue.

If I configure an AP for a static channel assignment it directly changs to a 40Mhz channel. If I revert it back to auto it keeps the 40Mhz channel width. It also changes from 36 to something.

Is there another workaround known ? We've got many AP's suffering from this issue unfortunately and I don't want to reconfigure them manually.

[Rasika Nayanajith]

Is it single WLC environment or multi WLC environment ?

Rasika

[aflbakker]

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2* 5520 HA setup (so 4 physical devices). they are in the same mobility domain but AP's from WLC X do not see AP's from WLC Y (geographically separated).

@Leo Laohoo I did not try disabling the DCA because it is production environment. What does happen if you disable it. Do all AP's revert to default values ? That would be bad in our case. 

[Leo Laohoo]

No, DCA will just STOP.
But I'm not saying "disable" DCA. I said "disable and re-enable DCA". So this means disable DCA, hit Apply, enable DCA, hit Apply.

[aflbakker]

:) Yes I understood it correctly.

I think we'll raise a TAC to verify. 

I'll keep the thread updated.

[aflbakker]

Here it is, verified by TAC : 

https://bst.cloudapps.cisco.com/bugsearch/bug/CSCvr20539/?reffering_site=dumpcr

[Leo Laohoo]

According to the Bug ID (if the integrity is to be trusted), disable and re-enable DCA will fix the issue. Has anyone tried this before?
If the issue persist, raise a TAC Case.