[ntp:questions] ntpdate function

Brian Utterback brian.utterback at oracle.com
Tue Apr 16 13:53:26 UTC 2013

On 04/15/13 12:48, unruh wrote:
> On 2013-04-15, Jacek Igalson <jacek.igalson> wrote:
>> In fact, I have used offset,
>> delay is recorded by the way.
>> It indicates how asymmetric might be the trip.
> No. It says nothing about the asymmetry. Just about the delay. Now you
> might make the assumption that a longer delay is probably a delay in
> only one leg of the path, implying asymmetry (which is what ntpd does in
> its clock filter algorithm) and that might often be a reasonable
> assumption, expecially if the delay is is say twice as long as usual, it
> is often a very bad assumption for slightly longer delays.

That was my first reaction when I read it. But I think that what he is 
saying is that delay tells you the *maximum* error that can be 
introduced by asymmetry. If the path were completely symmetric the value 
of delay would not matter.


Always code as if the guy who ends up maintaining your code will be a
violent psychopath who knows where you live. - Martin Golding
Brian Utterback - Solaris RPE, Oracle Corporation.
Ph:603-262-3916, Em:brian.utterback at oracle.com

More information about the questions mailing list