Bug ID 631530: TAI offset not adjusted immediately during leap second

Last Modified: Oct 01, 2018

Bug Tracker

Affected Product:  See more info
BIG-IP TMOS(all modules)

Known Affected Versions:
11.5.1, 11.5.1 HF1, 11.5.1 HF10, 11.5.1 HF11, 11.5.1 HF2, 11.5.1 HF3, 11.5.1 HF4, 11.5.1 HF5, 11.5.1 HF6, 11.5.1 HF7, 11.5.1 HF8, 11.5.1 HF9, 11.5.2, 11.5.2 HF1, 11.5.3, 11.5.3 HF1, 11.5.3 HF2, 11.5.4, 11.5.4 HF1, 11.5.4 HF2

Fixed In:
11.5.4 HF3

Opened: Dec 02, 2016
Severity: 3-Major
Related AskF5 Article:


When repeating a UTC time value during a leap second (when UTC time should be 23:59:60), the International Atomic Time (TAI) timescale should not stop, the kernel increments the TAI offset one second too late.


Impact to applications unknown, system will stay stable and a timer may be fired off later than expected.


This occurs during an NTP leap second event, for example an event occurs on December 31, 2016, at 23:59:60 UTC



Fix Information

International Atomic Time (TAI) offset during leap second has been corrected.

Behavior Change