We have contacted TAC on this issues, and they haven't given us a good resolution yet.
This is what they sent:
My understanding for what you seem to be telling me to do is to set all of our controllers to UTC (config time timezone 0 0) as a workaround for the change in daylight savings time dates here in the U.S. However, it seems that if we do this our controllers will not be synchronized with the rest of our environment. (because everything else will be configured for -6 GMT)
I was led to believe that the controllers are time sensitive. We have experienced AP's failing to assign to a WLC when the time is incorrect. We do not want to experience any issues with all of our wireless networks because of a time issue.
The Wireless Network Business Unit at Cisco recommends setting the timezone value to 0 on all controllers so as to avoid any issues of time difference across the border if you have systems scattered over different time zones ( would result in all your controllers running on the same time, irrespective of their timezones).
But based on our conversation, it appears this may not be a feasible solution for you organization. I would suggest that you set the time manually on all your controllers ,on Daylight savings date to read the right offset value. For example, if you NTP is operating at GMT and you wish to set daylight savings on your controllers, you would do:
config time timezone -5 0
Your WCS and Location server will be running on Daylight savings time already, because they will be running on their machine time, which is automatically updated by their OS.
No, you will not have any issues with the APs. I did speak to the engineer who handled your previous issue. There should not be a problem this time.
If we leave all of our WLC's alone will we have an issue?
No, you will not have any specific issues.However, the time on the controllers will be an hour off the original time. The only thing that will really be effected if you don't change it is the time the controller reports. This would include log entries. If that is not an issue, then you really don't need to change the time
Should we plan to manually configure all of our WLC's on the new daylight savings time date?
Depends on whether you want to change the time.If yes,then you should manually configure the controllers .