[ntp:questions] tool to collect statistics on round trip delay offset?

Maarten Wiltink maarten at kittensandcats.net
Thu Oct 26 15:09:22 UTC 2006

"joe blow" <someone at msn.com> wrote in message
news:e7S%g.66382$uH6.48179 at twister.nyroc.rr.com...
> I have multiple servers that I want to be in sync to < 1ms (200-300
> usec ideally).

Okay. NTP can do that easily, if you run nothing else on them.

> It is not so important how well these match to GMT, ...

...to you.

> The standard out of the box NTP takes way too long to stabalize ...

...to you.

> [...] Since my network will be closed (and small - all in the same
> room), with only 2 NTP servers (one for backup), I'm expecting very
> small variations in measurements, and thus only a small amount of
> filtering should be required.

I regret to inform you that NTP was engineered to work for other people,
too. Feel free to commission your own product or to hack the - freely
available - source to NTP.

That does not mean that configurations don't exist that would suit you
better than what you have now. Perhaps a PPS source distributed to all
your nodes? That should get them in very tight synchronisation.

If you want them synchronised the soonest after you come in in the
morning, I would recommend not turning them off overnight. Not just to
be lazy, although it is also the simplest solution, but mostly because
it minimises frequency changes all around. The less the server's
frequency excursions, the easier for the clients to follow them. The
less their own excursions, likewise.

Maarten Wiltink

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