[ntp:questions] Re: NTP and DCF77 leap logs

David L. Mills mills at udel.edu
Fri Jan 6 19:12:25 UTC 2006


Please lapse back into engineering mode and reformulate your opinion. 
Seriously consider what happens when (a) upstream sources indicate a 
leap and the kernel does not implement a leap function, (b) the radio 
does not recognize the leap warning and steps only some minutes later, 
(c) one or more samples of extreme error arrive outside the step 
threshold and then return to nominal, (d) there is no advance warning 
and the upstream sources step on or after the leap. Once you consider 
these cases in detail and provide a compromise solution, I would be very 
happy to learn your opinion. Meanwhile, the envelope of acceptable 
behavior is the current implementation.


Serge Bets wrote:

>  On Thursday, January 5, 2006 at 15:53:46 +0000, David L. Mills wrote:
>>the only acceptable behavior is either to obey the leap as designed or
>>to ignore the leap and coast for 17 minutes one second off the sources
>>and then step to the correct offset. The frequency should not be
> With all due respect, I'll formulate the following opinion: The coast
> and step behaviour can't be placed in the acceptable category.
>  - Gives wrong time on the machine.
>  - Serves wrong time to downstream clients.
>  - Does a step backward at some unpredictable moment.
>  - Depends on sources leaping well or not.
> Serge, frightened.

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