Unexpected channel shifts from configured channels in Cisco APs

[roshney-roy]

Hi Experts,

We are using a licensed Cisco Catalyst 9800-CL Wireless Controller to manage our Cisco APs (models C9124AXE and AIR-AP1526E-Z-K9). According to our wireless network requirements, the channels on the APs are manually configured for both the bands(2.4 & 5 Ghz)

However, we are experiencing an issue where the AP channels are changing automatically despite the manual configuration. This is particularly noticeable with the 2.4 GHz channels, which tend to shift significantly.

We would appreciate any insights or suggestions on how to resolve this issue.

Thank you!

Regards,

Roshney Roy

[Flavio Miranda]

@roshney-roy 

 Do you have Dynamics channel assignment algorithm set as Off on the DCA?

[roshney-roy]

Yes Flavio, DCA is off.

[Flavio Miranda]

Only a Bug Can explain this.

[roshney-roy]

It is possible.

[Scott Fella]

I get it, just haven't come across this in a very long time. Let us know what TAC finds.

[Scott Fella]

That should not happen on 2.4GHz, but on 5Ghz, you have to adhere to the rule for DFS channels. Also this is where you have the channel being defined?

If you are seeing this issue, you might just want to open a TAC case so they can look at your configuration and code you are running. I have not seen folks hard code the channels in a very long time.

[roshney-roy]

Hi Scott,

Thanks for your reply. We have manually configured the channels the way you have mentioned above. But the channel changes despite of the Custom configuration. Regrading the 5GHz channels, we have configured our channels on Non-DFS ones. Cisco TAC is also trying their best to resolve this issue.

The manual configuration of the channels is a mandatory requirement of our wireless network.

[Scott Fella]

I would then assume it is a bug on the version you are running.  Can I ask, why is it mandatory?  Is it a device specific from a vendor that requires this, because devices have come a long way where this is never required.

[roshney-roy]

Yes, it is a requirement at the access end of 2.4ghz to make the channel static. We are already in touch with Cisco TAC to resolve this issue.

[Gaurav Kansal]

Dear Roshney,

Can you please share the current version of your controller and also is there any finding on this by TAC ?

Regards
Gaurav Kansal

[roshney-roy]

Hi Gaurav,

Our Cisco catalyst controller 9800 is on version 17.9.5

Cisco TAC is still trying to troubleshoot the issue.

[srimal99]

@roshney-roy 
You can check for bug for on following links
https://www.cisco.com/c/en/us/support/web/tools-catalog.html
https://www.cisco.com/c/en/us/support/web/tools/bst/bsthelp/index.html
https://bst.cisco.com/bugsearch

[roshney-roy]

Thanks srimal99 for sharing the link. We will check that out.

[roshney-roy]

Cisco TAC has identified the bug "CSCwj08558" and has recommeded a firmware upgrade (17.15.1)