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Cisco Wide Area File Services Software (WAFS)

Field Notice: FN - 62896 - New Zealand Daylight Saving Time Policy Changes Effective September 2007 - For Cisco WAAS, WAFS, ACNS


September 5, 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

ACNS

All versions of ACNS

WAAS

All versions of WAAS

WAFS

All versions of WAFS

 

Problem Description

The operating systems of most Cisco products that support Daylight Saving Time (DST) have built in mechanisms to automatically change the times, based on current user-selected rules. Once the new DST is implemented, the time on devices that maintain time zone information will continue to change according to the old method, unless changes are made.

Any time-dependent product features of WAAS, WAFS or ACNS will be affected by this problem unless you move to the appropriate software image or apply the workaround as herein described.

Background

On April 30, 2007, the Minister of Internal Affairs issued a statement regarding a change in Daylight Saving Time policy for New Zealand. The change in policy has modified the start and end dates for Daylight Saving Time (DST). Beginning in 2007 and beyond, Daylight Saving Time in New Zealand will start on the last Sunday of September at 2:00 A.M. local time and end on the first Sunday of April at 3:00 A.M. local time.

Specifically for 2007-2008, Daylight Saving Time will begin at 2:00 A.M. local time on September 30, 2007, and end at 3:00 A.M. local time on April 6, 2008.

For more information, see the statement issued by the Minister of Internal Affairs: Daylight saving to be extended.

The old Daylight Saving Time policy dictated that DST started on the first Sunday in October and ended on the third Sunday in March.

Problem Symptoms

Impact to Networking Systems

Any time-based function may be off by one hour. Log file timestamps will not be accurate, time-based routing systems may not engage/disengage at the desired time, displays may be one hour off, and so on.

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. 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

Solution:

Migrate to a software releases which has the new summertime rules, OR implement the suggested workaround. Workaround instructions apply to all 3 applications, and are the same for each.

A fix will be checked into ACNS 5.4.7 and 5.5.x release.

A fix will be checked into WAAS 4.0.x release.

A fix will NOT be checked into WAFS release, please follow workaround instructions.

Workaround:

Set the time zone to a generic zone and then create your own summertime settings for that zone. Running the two clock commands noted below on all your U.S. based CE's, FE's and WAE's would:

1) change them to a generic time zone with no DST

2) add a custom summertime setting that would automatically adjust the clock by 60 minutes.

The following example is for a time zone 5 hours behind Greenwich Mean Time (GMT-5). You would need to specify the offset that is appropriate for your time zone.

clock timezone GMT-5 -5 0 
clock summertime GMT-5 recurring 2 Sunday March 2:0 2 Sunday November 2:0 60

The first command sets a generic time zone that does not have daylight savings time associated with it. The second command sets the time back on the second Sunday in March at 2:00 A.M. through the second Sunday in November at 2:00 A.M., and changes the time by 60 minutes.

Link to download Cisco Application Networking Software (registered customers only) .

DDTS

To follow the bug ID link below and see detailed bug information, you must be a registered user and you must be logged in.

DDTS

Description

CSCsj93996 (registered customers only)

WAAS New Zealand Daylight Savings Time Update

CSCsk20769 (registered customers only)

ACNS New Zealand Daylight Savings Time Update

 

Revision History

Revision

Date

Comment

1.0

05-SEP-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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