Does anyone have any information on how Cisco is going to handle the daylight saving time changes in 2007 for router and switch IOS's? Will it be some type of patch or will we need to update the IOS level on all of our switches and routers?
There are two choices, either upgrade the IOS to a version which has the fix or perform a workaround.
Here's some more detail (from caveat CSCsg70355)
Symptoms: Starting in calendar year 2007, daylight savings summer-time rules may cause Cisco IOS to generate timestamps (such as in syslog messages) that are off by one hour.
Conditions: The Cisco IOS configuration command, clock summer-time zone recurring, uses United States standards for daylight savings time rules by default. The Energy Policy Act of 2005 (H.R.6.ENR), Section 110 changes the start date from the first Sunday of April to the second Sunday of March, and it changes the end date from the last Sunday of October to the first Sunday of November.
Workaround: A workaround is possible by using the clock summer-time configuration command to manually configure the proper start date and end date for daylight savings time. After the summer-time period for calendar year 2006 is over, one can for example configure:
clock summer-time PDT recurring 2 Sun Mar 2:00 1 Sun Nov 2:00
(this example is for the US/Pacific time zone)
HTH - plz rate if useful
It makes no difference whether the devices are synced to NTP. NTP communicates in terms of UTC and does not have any information about time offsets or about daylight savings time. All of the control for time offsets and daylight savings time are done with the clock command in global configuration. You will need to make changes in the clock summertime configuration command to accommodate the changes.
This was very helpful, I will definitely provide a good rating.
Two quick questions: 1) Where can we find out which IOS Versions have the fix in them? and 2) If we use the workaround in our devices what would the command look like for EDT? And, does this pertain to all devices (router/switch, etc.)?
I am not real sure where to look to find that. But as one data point I just looked at a router running 12.2(28) (I believe the IPBase feature set) and it had support for this fix. So it looks like the fix has been around for a while.
For EDT the command would look like this:
clock summer-time EDT recurring 2 Sun Mar 2:00 1 Sun Nov 2:00
I have not been able to find a specific statement about which IOS versions have this. I checked the command reference and it seems to indicate that it goes back to 10.0. I found an old command reference for 10.3 which does include the workaround to supply the dates for beginning and ending of daylight savings time. So I do not believe that any of us need to worry about trying to implement this and finding that it is not supported in the IOS that we are running.
I'm confused about one of the versions that this is supposed to be fixed in. It says "12.1(22)EA09". I've never seen this version before, and cannot find it anywhere. Currently we are at 12.1.22EA5a.
I think that there are several things in the writeup of that issue that do not make sense. In particular the bug is NOT "fixed" but they provide a workaround. So the "fixed in" list is kind of odd. And my research looks like the work around (fix) has been in the code since 10.0.
So my suggestion is to go to one of your routers, go into config mode, and see if the clock summertime command contains the ability to specify the start and stop dates. I am confident that it will.
side note: the essence of the problem in the bug is that the defaults used by the command are no longer appropriate. Until Cisco releases code with new default behavior it will not be fixed. But with the ability to specify the start and end dates we have an excellent workaround. It just means that we can no longer just accept the default dates.
We're running IOS Version 12.2(18)S XF6, where would I find out if this already has the fix. Any info would be greatly appreciated.
I am confident that your router does have the fix. To check to verify if your router has the fix go into config mode, and do this:
if on line help indicates that you can input week to start, or first week of the month, or last week of the month, then your code does have the fix.
Just in case you still need more information: