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CiscoWorks Network Compliance Manager

Field Notice: FN - 62750 - U.S. Daylight Savings Time Fix/Patch for CiscoWorks Network Compliance Manager


March 8, 2007

NOTICE:

THIS FIELD NOTICE IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTY OF MERCHANTABILITY. YOUR USE OF THE INFORMATION ON THE FIELD NOTICE OR MATERIALS LINKED FROM THE FIELD NOTICE IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS FIELD NOTICE AT ANY TIME.


Products Affected

Products Affected

Comments

CiscoWorks Network Compliance Manager (CWNCM)

Ver 1.2

Problem Description

The Daylight Savings Time (DST) change is going to affect many network devices, and could, without correction, cause disruption to time-sensitive network applications, result in incorrect log timestamps, and cause inaccurate audit and compliance reports. Thus the ability of an organization to continue operating at peak efficiency is tied to the ability to accommodate the change in DST.

Background

On August 8, 2005, the Energy Policy Act of 2005 (H.R.6.ENR), was signed into law. Section 110 of this Act modified the time change dates for Daylight Saving Time (DST) in the U.S.

Beginning in March of 2007, DST will begin on the second Sunday of March and end the first Sunday of November.

For 2007 and beyond, the daylight saving time period will be:

2:00 A.M. on the second Sunday in March

to

2:00 A.M. on the first Sunday in November

For more information on the Energy Policy Act of 2005, see H.R. 6. (See Section 110)

Problem Symptoms

Impact to Networking Systems

Networking systems often make use of local time to mark logs, as well as to schedule certain events, such as IP SLA schedule starts, or the beginning or end of a time-based access-list.

In addition, inconsistencies between time zone definitions may impact event correlation systems as well as other management systems relating to problem escalation. Having accurately represented local time is a very big concern for most organizations. Local time may be reflected in logs and on phone displays. This is especially true of systems that require accurate time and time stamping for proper operations.

For networking systems, the clock or clock source is often derived from a trusted chronological source such as a private or public Atomic clock, often through Network Time Protocol (NTP). NTP communicates time in Coordinated Universal Time (UTC), colloquially known as GMT, and thus is not impacted, nor is a workaround for statutory time zone changes. Local time definitions, including summertime settings are part of the configuration of most Cisco products.

Network Time Protocol (NTP) Implications

Regardless of whether or not network components are configured to use differing clock sources such as UTC and NTP, networks will be affected when clock summer-time commands are enabled with incorrect parameters.

Workaround/Solution

The following updates will be needed:

- Patch NCM with the DST patch (Details given below)

- Update the time on the NCM server itself to reflect the DST time. Please follow the respective OS guidelines on how to change time.

- Update the time on the devices using NCM.

NCM DST Patch

The NCM DST patch can be found at the CiscoWorks Network Compliance Manager Software Download (registered customers only) page. Use the file NCM_DST_Patch.zip. Documentation on how to install this patch can be found within the NCM_DST_Patch.zip file itself.

There are three major solutions to the DST issue on the device, which can all be dramatically automated by NCM:

  1. Device OS Upgrade: Upgrading the devices in the network to an appropriate version of device OS code that supports the new Daylight Savings Time calculations. NCM can track the success and failure of device OS uploads, and verify that they proceed quickly and accurately. Users of the NCM product have updated device OS code on thousands of devices in only an hour or two.

  2. Switch to UTC: As UTC (GMT) is a Universal Time zone that is unaffected by the yearly switch to Daylight Savings, UTC is an excellent choice to avoid confusion in the networking environment and can serve as a means to validate and coordinate all network device activities and logs against a standard, universal time zone. NCM can be used almost effortlessly to switch devices to using UTC as their time zone of choice. This change can be pushed out to thousands of devices simultaneously with NCM.

  3. Change Summertime Calculations: Some devices, including Cisco IOS devices have commands that can be placed in device configurations to manually enforce a changed DST calculation. Again, NCM can easily upgrade an entire IT infrastructure to use these correct calculations for DST.

For more information on the specific, technical aspects of the DST issue, see FN - 62613 - U.S. Daylight Savings Time Policy Changes Effective March 2007 - for Cisco IOS Software.

Revision History

Revision

Date

Comment

1.0

08-MAR-2007

Initial Public Release

For More Information

If you require further assistance, or if you have any further questions regarding this field notice, please contact the Cisco Systems Technical Assistance Center (TAC) by one of the following methods:

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