[ntp:questions] Re: Stratum1 ntp problems

Richard B. Gilbert rgilbert88 at comcast.net
Fri Aug 5 19:23:25 UTC 2005

Eugen COCA wrote:

>Supposing I have a Stratum 1 time server and the time delivered by the
>GPS receiver is wrong (without searching the cause for the moment). The
>result may be like this:
>ntpq> host xxxxxtime.xxxx.xx
>current host set to xxxxxtime.xxxx.xx
>ntpq> pe
>     remote           refid      st t when poll reach   delay   offset
> LOCAL(0)        LOCAL(0)        12 l    4   64  377    0.000    0.000
> 0.004
>*GENERIC(0)      .GPS.            0 l   62   64  377    0.000  2000.00
> 0.489
> PPS(0)          .PPS.            0 l  711   64    0    0.000    0.000
>(captured Fri Aug  5 14:58:15 UTC 2005).
>The server is in sync, reporting Stratum1, and the time is 2 seconds
>Are there any tricks to avoid this very unhappy problem ?
>P.S. The example is from a real, well known Stratum 1 time server
>(technically speaking, it's irrelevant to write the real name here).
I think you had better get a little more specific here!!

What hardware platform and what O/S are you using?  What version of 
ntpd?  How long has ntpd been running at this point?  What does your 
ntp.conf look like?  Is your PPS source part of your GPS receiver?   Why 
does it show as unreachable (reach= 0)?

If you are running either Windows or Linux, on an Intel platform (or 
equivalent) and the system gets really busy for a while, you can lose 
clock interrupts which will put your local clock way off.

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