Re: Mobility Express 8.8.111.0: Unable to set DCA channel width to 40MHz

ANDREAS LIEBE · ‎03-04-2019

I'm running ME8.8.111.0 in a small setup with 3 APs and was wondering why DCA with channel-width "best" sticks with 20MHz channels. I tried to set them to 40MHz instead of "best":

>config advanced 802.11a channel dca chan-width 40
ERROR: Configured DCA channels are in invalid combination for selected Channel Width.

Checking the channels looks normal to me:

Leader Automatic Channel Assignment
  Channel Assignment Mode........................ AUTO
  Channel Update Interval........................ 600 seconds
  Anchor time (Hour of the day).................. 0
  Update Contribution
    Noise........................................ Enable
    Interference................................. Enable
    Load......................................... Disable
    Device Aware................................. Disable
  CleanAir Event-driven RRM option............... Enabled
  CleanAir Event-driven RRM sensitivity.......... Medium
  CleanAir Event-driven RRM Rogue Option......... Disabled
  Channel Assignment Leader...................... aplnt1 (192.168.1.1) (::)
  Last Run....................................... 430 seconds ago
  Last Run Time.................................. 0 seconds
  DCA Sensitivity Level.......................... MEDIUM (15 dB)
  DCA 802.11n/ac Channel Width................... BEST
  DBS Max Channel Width.......................... 40 MHz
  DCA Minimum Energy Limit....................... -95 dBm
  Channel Energy Levels
    Minimum...................................... -86 dBm
    Average...................................... -86 dBm
    Maximum...................................... -86 dBm
  Channel Dwell Times
    Minimum...................................... 12 days, 03 h 31 m 44 s
    Average...................................... 37 days, 10 h 04 m 25 s
    Maximum...................................... 79 days, 03 h 07 m 18 s
  802.11a 5 GHz Auto-RF Channel List
    Allowed Channel List......................... 36,40,44,48,52,56,60,64,100,
                                                  104,108,112,116,120,124,128,
                                                  132,136,140
    Unused Channel List..........................
  DCA Outdoor AP option.......................... Disabled

Any idea why the controller complains about an invalid combination?

Thanks,

Andreas

patoberli · ‎03-05-2019

That is weird. What country do you have configured?

ANDREAS LIEBE · ‎03-06-2019

country is set to DE:

>show sysinfo
...
Configured Country............................... DE  - Germany

patoberli · ‎03-06-2019

This looks fine then. I currently tend to say it's a bug. Can you try to reboot the master controller? I wonder if that will help.
What happens if you change this in the GUI?

ANDREAS LIEBE · ‎03-06-2019

Thanks for your hints.

Unfortunately changing the GUI settings yields the same error message. Rebooting did not help either.

patoberli · ‎03-07-2019

If you like to experiment a little, sign up here for the latest beta release of 8.8: http://cs.co/88Mr2InterimAccess
Forum thread about the release: https://community.cisco.com/t5/other-wireless-mobility-subjects/88mr2-interim-build-availability/td-p/3798882
It is an officially supported release for production environments, so the software is already quite stable.