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Cisco Unified Mobility

Field Notice: FN - 62670-Daylight Savings Time policy changes effective March 2007 - for Mobility Manager


Feburary 06, 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

MobilityManager 1.2 (1)

MobilityManager 1.2 (2)

MobilityManager 1.2 (3)

Problem Description

Daylight Savings Time changes have been mandated by the Energy Policy Act of 2005 (H.R.6.ENR), Section 110. These changes will go into effect in March 2007.

The Operating Systems of most Cisco products that support Daylight Savings Time have built in mechanisms to automatically change the times, based on CURRENT United States rules. Once the new Act is implemented, the time on devices that maintain time zone information will continue to change according to the OLD Rules, unless changes are made.

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 a.m. on the second Sunday in March to 2 a.m. on the first Sunday in November

For more information please visit Energy Policy Act of 2005 (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 (i.e. UTC, NTP, etc.) networks will be affected when "clock summer-time" commands are enabled with incorrect parameters.

Workaround/Solution

Cisco Unified MobilityManager is an appliance which runs on a Linux based operating system. MobilityManager version 1.2 (4) which will include the required US DST fixes is expected to post for download here: MobilityManager 1.2(4) download sometime around mid-February 2007.

Revision History

Revision

Date

Comment

1.0

02/06/2007

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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