Saturday, April 5, 2008

Daylight Saving Time on Cisco Devices

Much of our infrastructure is made up of Cisco devices. These include 1130 wireless access points, 1720 routers, 3750 Catalyst switches, Unity Express voice mail systems, as well as some additional devices not relevant to this post. Due to the change in the effective dates for Daylight Saving Time, we had to make a lot of different changes to our Cisco devices. During this process we found that there are different ways to approach different devices. For example, the 1130 AP and 1720 routers don't use NTP (Network Time Protocol) but they use SNTP (Simple Network Time Protocol). This is an important distinction because as you try to make sweeping changes in a large environment, you have to know that certain devices require one extra letter as compared to all of the other devices.

So, the config for the Cisco AP and 1720
config t
!
clock timezone EST -5
!
clock summer-time EDT recurring 2 Sunday March 02:00 1 Sunday November 02:00
!
sntp server 192.168.x.x
!
exit
!
show clock
!

As seen above, with Cisco's IOS you can easily set the timezone, start and end date for Daylight Saving Time, as well as the SNTP server's address.

As for all of the other Cisco devices (at least in our infrastructure) the config is as follows:
config t
!
clock timezone EST -5
!
clock summer-time EDT recurring 2 Sunday March 02:00 1 Sunday November 02:00
!
sntp server 192.168.x.x
!
exit
!
show clock
!

Unfortunately, there was still one more change that needed to be made. The Unity Express voice mail module doesn't use the timezone settings for whatever devices it is installed in, it has its own settings, which seems silly, but I guess someone had a use for it.

To access the Unity Express module you must first enter IOS for the host device, then the "Service Engine" that is running Unity Express. The following is the command that I used to configure this for our Unity Express time zone:

service-module service-Engine2/0 session

This will start the telnet session with unity express

The system will need to be changed to EST (New York - for Fall) or AST (Bermuda - for Spring) using the command
clock timezone

This command will present a menu

For EST choose:
2) Americas
then
45)United States
New York


For AST choose:
6)Atlantic Ocean
Bermuda


The system must then be reloaded (taken offline). This was the only way that I could get the Unity Express module to stamp the voice mail messages with the correct time. This means, that each March and November, I am going to have to perform this to get the messages stamped properly.

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