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Cisco VCS Leap Second Bug - Other Feasible workarounds

RAMEEZ RAHIM
Level 1
Level 1

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 Alumni
VIP Alumni

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 Alumni
VIP Alumni

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 mark helpful responses and to set 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

Please remember to mark helpful responses and to set your question as answered if appropriate.