[time-nuts] NTP stratum 0

Rob Kimberley time.bandit at btinternet.com
Sat Jan 14 13:48:16 EST 2006

The Stratum numbers in the Telecom Sync industry and those used in NTP
hierarchy are different beasts. In Telecom Sync, Stratum 1, 2, 3 et al are
internationally defined levels of frequency accuracy. In NTP Stratum 1
merely means the top of the hierarchical pyramid with Stratum 2, 3 etc below
it. Stratum 0 has been used in discussions I have seen from people at Datum
and TrueTime to represent a GPS/NTP reference, but realistically I believe
that it should be labelled as Stratum 1.

Would  humbly suggest you take a look at www.ntp.org for more information.

Rob Kimberley


-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Hal Murray
Sent: 14 January 2006 18:35
To: albertazzi.mich at tiscali.it; Discussion of precise time and frequency
Subject: Re: [time-nuts] NTP stratum 0

> I would like to know where could I find the FORMAL specification of 
> the NTP stratum 0.

I assume you are looking for some sort of quality requirements like the
telephone industry has for their various stratum levels.  I don't think you
will find it.

Basically, stratum 0 is anything from outside NTP.  The "0" doesn't promise
any quality.

There is a mechanism within ntpd for the driver to report a quality

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