nanog mailing list archives

Re: anyone running GPS clocks in Southeastern Georgia?


From: "Robert E. Seastrom" <rs () seastrom com>
Date: Fri, 21 Jan 2011 17:37:46 -0500

Gary Buhrmaster <gary.buhrmaster () gmail com> writes:

NTP isn't going to be the only "ripple".

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.

Gary

(*) This presumes that this test results in loss of signal
    lock, and not intentionally injected false information.

Seeing the ripples also presumes that people are monitoring their NTP
system health more closely than just looking at the output of ntpq -p.  :)

-r




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