[ntp:questions] Server offset included in served time?

Uwe Klein uwe_klein_habertwedt at t-online.de
Tue Sep 16 08:45:50 UTC 2008


David Woolley wrote:
> Uwe Klein wrote:
> 
>>
>> Does ntp serve "system" time or "correct" time to clients?
> 
> 
> NTP serves system time, which its algorithms believe to be the best 
> practical estimate of correct time within statistical error.  What we 
> are talking about here is making that assumption more valid during 
> startup transients.
> 
> Basically, as far as NTP is concerned, there is no difference between 
> system time and correct time.  (Earlier versions used to serve a 
_________________________________^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> corrected time during slew recoveries, but not during normal operation.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

>  That would not make a difference for the 120ms case discussed here, as 
> that uses the normal control loop.)

The second paragraph seems to answer my question. ( afaiu )

This would implicate that clients syncing to a ( both freshly started )
slewing server will be presented with an offset that is
( to make it interesting ) slewing too.

Doesn't this lead clients to first slew towards the servers offset and
than in a chained way slew back to the "right" time together?
( assumed the client came up at the same time and with a better/other match )

uwe




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