[135334] in North American Network Operators' Group
Re: anyone running GPS clocks in Southeastern Georgia?
daemon@ATHENA.MIT.EDU (Cutler James R)
Fri Jan 21 16:54:35 2011
From: Cutler James R <james.cutler@consultant.com>
In-Reply-To: <AANLkTim=Rks3MH+ySoYHYKaauZkhgV1-xJ05wXLxi=wE@mail.gmail.com>
Date: Fri, 21 Jan 2011 16:53:08 -0500
To: nanog group <nanog@nanog.org>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On Jan 21, 2011, at 4:45 PM, Gary Buhrmaster wrote:
>> NTP isn't going to be the only "ripple".
>=20
> Most of the "brand name" GPS NTP solutions have a clock
> with is more than stable enough to survive without GPS
> lock for 45 minutes(*). Some of the more expensive units with
> temperature controlled oscillators have hold times in the
> many weeks. My guess is that the NTP ripples will be
> limited to those NTP servers just (or recently) booted
> which have not yet achieved a stable clock state.
>=20
> Gary
>=20
> (*) This presumes that this test results in loss of signal
> lock, and not intentionally injected false information.
>=20
Even if there actually was an "NTP ripple", a properly designed NTP =
solution should rely on at least three geographically diverse sources. =
Given the ubiquity of the internet this is not difficult to achieve, =
barring extreme circumstances.
James R. Cutler
james.cutler@consultant.com
