[ntp:questions] different request pattern

arne_woerner at yahoo.com arne_woerner at yahoo.com
Mon Jun 30 21:02:31 UTC 2008


On Jun 30, 8:15 pm, David Woolley
<da... at ex.djwhome.demon.co.uk.invalid> wrote:
> arne_woer... at yahoo.com wrote:
> > it when i compare the "offset per second" (ops) to previous ops of
>
> What is "offset per second"?
>
oh - i mean:
1. "offset" in the sense of "ntpq"... estimated offset to the server
clock...
and
2. "offset per second" describes the estimated offset-difference after
a second...
i compute it like this (dont laugh :-) ):
(adjtime_offsets + estimated_offset_to_server_X)/T
let T be the time when the offset to server X was 0
let adjtime_offsets be the sum of the adjtime() offsets in the last T
seconds...

> > then i found that the official ntpd algorithm doesnt propagate false
> > tickers to its clients fast enough, so that they start building a
>
> I don't believe you are describing "false tickers" in the NTP sense.  My
> guess is that you are assuming a lower rate of dispersion than NTP
> and/or assuming that the asymmetry of the propagation delays is limited
> to a lot less than 100%.
>
hal (dot) ikw (dot) Uni (dash) Osnabrueck (dot) DE. (A) had that
problem for some days:
2 servers(+) had an offset of about +20ms and the *-server had an
offset of about -10ms...
this continued for days, even though the refid of the *-server
referred to a false ticker
(server marked with an "x")...
i think A's ntpd is old...
the consequence was that A's "ops" value was rather consistent within
A's ops-history,
but not consistent with the sample of the previous server...

-arne




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