Handling adjustments to Coordinated Universal Time (UTC)

Article ID: SCHD0001 Periodically, UTC is adjusted to maintain global synchronization. These "Leap seconds" are applied randomly when necessary.


After the leap second occurs, computers - unsynchronized with an external time server - will be one second faster than the actual time.


Leap seconds are a periodic one-second adjustment of Coordinated Universal Time(UTC) in order to keep a system's time of day close to the mean solar time. This time difference is usually resolved on each computer at the next time synchronization when using an external time source.



Systems running Network Time Protocol (NTP) should automatically account for leap second corrections by synchronizing their local timekeeping with an NTP server. 

Timestamps exchanged in Precision Time Protocol (PTP)  are in TAI (International Atomic Time) format which does not contain leap seconds.  Kernel flags are used to insert a leap second as the system clock continues to run in UTC. The kernel will then insert the leap second as normal.

Computers not using NTP or PTP to synchronize their timekeeping will not self-correct and the time reported by these systems will have a one-second difference relative to UTC after the leap second correction. You should reset the clock manually after leap seconds occur.

Recommend all CommCell component hosts use a time service protocol with a time server synchronized with an external time source..  

For more information see:

How the Windows Time service treats a leap second.

Resolve Leap Second Issues in Red Hat Enterprise Linux