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RAMEEZ RAHIM
Beginner

Cisco VCS Leap Second Bug - Other Feasible workarounds

Can we change the NTP server to a in-existent IP or block the reachability to NTP server to workaround the below Bug.

Upgrade or a Planned Reboot doesn't seem feasible. Kindly suggest

 

Update timezone data to include addition Leap Second introduced on 30-Ju
CSCut30577
Symptom:
There are periodic leap second events which can add or delete a second to global time. 
When the leap second update occurs system may hang since operation system won't understand "60" seconds (normally clock goes from "59" second to "00" second).

Conditions:
The leap second update will be propagated via Network Time Protocol (NTP).

Workaround:
Option #1: An upgrade is required.
Option #2: Shutdown the system prior to leap second occurs and start up after this event bypass the leap second event.

Further Problem Description:
Fix in X8.5.2 code.
1 ACCEPTED SOLUTION

Accepted Solutions
Wayne DeNardi
VIP Advisor

It's only going to be a problem on your device if it happens to query the NTP server at the exact time that it responds with "60" as the seconds... a second before, or a second later, and it'll be alright, so I'd think you'd need to be pretty unlucky to hit this bug.

But, yes, you could assign the VCS a non-existant, or unreachable NTP server over that time period, in which case it then won't query anything to get the "60" second time, then return it to normal operation afterwards.

Wayne
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Wayne
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View solution in original post

3 REPLIES 3
Wayne DeNardi
VIP Advisor

It's only going to be a problem on your device if it happens to query the NTP server at the exact time that it responds with "60" as the seconds... a second before, or a second later, and it'll be alright, so I'd think you'd need to be pretty unlucky to hit this bug.

But, yes, you could assign the VCS a non-existant, or unreachable NTP server over that time period, in which case it then won't query anything to get the "60" second time, then return it to normal operation afterwards.

Wayne
--
Please remember to rate responses and to mark your question as answered if appropriate.

Wayne
--
Please remember to rate responses and to mark your question as answered if appropriate.

May I know which time zone it is affecting or it is affects the local time zone?

i.e GMT will affects at their 23:59:59 but GMT+8 time zone will be affected 8 hours later. 

The official answer is that it happens when the UTC time clock changes - so there will be that one second after 23:59:59 where the clock reads 23:59:60 before going to 0:00:00.

See https://en.wikipedia.org/wiki/Leap_second

Wayne
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Please remember to rate responses and to mark your question as answered if appropriate.

Wayne
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Please remember to rate responses and to mark your question as answered if appropriate.
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