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Spirent TestCenter: Why does the IEEE-1588v2 emulation send an Announce message with 36s offset?

Environment/Versions
  • v4.47
  • IEEE-1588v2 emulation
Answer
  • The OriginCurrentUTCOffset in the Announce packet is just to say which epoch time we are using. 
    • It’s in the 1588 spec, 7.2.3 page 42. 
  • Basically we are saying our clock is 36 seconds ahead of UTC time. 
    • This is a standard number which basically represents the number of leap seconds from PTP epoch (http://en.wikipedia.org/wiki/Leap_second). 
    • The UTCOffset value was changed in June 2015 to 36.  This offset has no relation to local offset of the master clock that is received by the slave. 
    • This value on the Spirent TestCenter application is user configurable.

Product : Spirent TestCenter,IEEE 1588