What is the IMPACT to Cisco Routers with the Daylight Savings Time Change?

[gokada]

I would like to ask the impact of the new law passed that changes the Daylight Savings Time. What do we engineers need to do to the routers and switches?

[Richard Burts]

Gregory

This is an interesting point and I am a bit surprised that I am not seeing more discussion about this. If we do not do something different in our configs then when the daylight savings time change happens in the spring our routers and switches will not change time at the "correct" date. You would have to assess within your own organization what is the impact of having time stamps that are an hour off.

The good news is that Cisco has prepared for this. In recent versions of IOS there are options where we can specify the start date and end date for daylight savings time.

router1(config)#clock summer-time EDT ?

date Configure absolute summer time

recurring Configure recurring summer time

router1(config)#clock summer-time EDT date ?

<1-31> Date to start

MONTH Month to start

HTH

Rick

[wiluszm]

Excellent question! There is a Cisco bug opened for the issue... CSCsg70355. For those not wishing to update to an IOS to fix the issue (IOSs are listed under the bug ID) can enter the following command on all network devices to make changes for the new law:

clock summer-time recurring 2 Sun Mar 2:00 1 Sun Nov 2:00

I hope this answers the question. I'll also put this up on my blog as I'm sure others are wondering about the issue.

-Mike

http://cs-mars.blogspot.com