Re: Using iburst and pools

[Gary E. Miller]

Yo Paul!

On Thu, 19 Mar 2020 13:50:32 -0700
Paul Theodoropoulos via <address@hidden> wrote:

> > The problem at hand is that a user has local PPS and wants that time
> > to win the startup race, ahead of the more jumpy network chimmers.
> > It is maybe 1,000x more accurate and stable.
> >
> > To that end, a user places the PPS at the top of the ntp.conf, with
> > a short poll time than other refclocks, so that ntpd will select it
> > first.
> >
> > But, when you add in a bunch of marginal pool servers, from all over
> > the planet, and iburst them, then they win the race instead of the
> > nice local PPS.  ntpd starts out with the worst refclocks, not the
> > best.
> >
> > Eventually ntpd will sort it out, usually, but best to just pick the
> > local PPS on startup.  
> 
> So, if I may interject for my own clarity. For an ntp server with a 
> properly running GPS and PPS, in a stable environment with reliable 
> network, this would suggest that - regardless of pool *or* peer - it
> is best not to use iburst?

That would be my suggestion if normal startup quality is important to you.
I can see a corner case where your PPS/GPS is dead, and you are still
in a hurry to start.  But even that is minimal if you have a good RTC.

Since most people only very rarely restart their stratum 1, not a big
deal.

YMMV.

> As in, iburst is desireable for _client_ ntp devices, not for those
> that are themselves stratum one?

That would be a good rule of thumb.

> (I'd like to copy this and its answer to the ntpsec list, since it's
> most relevant there, if permissible)

Yeah, this whole discussion really belong there.

RGDS
GARY
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Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
        address@hidden  Tel:+1 541 382 8588

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