[ntp:questions] Synchronize clocks without a reference clock

Harlan Stenn stenn at ntp.isc.org
Mon Mar 19 21:14:11 UTC 2007


>>> In article <45fe723f$0$69886$e4fe514c at news.xs4all.nl>, "Maarten Wiltink" <maarten at kittensandcats.net> writes:

>> Does this mean that the maximum rate of change is 15 µs per second?

Maarten> No, that's something else, probably the worst-case estimate for how
Maarten> fast synchronisation deteriorates between server polls. But that's
Maarten> no more than a guess.

Maarten> The number I mean is the 500PPM cap on the observed drift that NTP
Maarten> will accept before giving up. You can't change that without
Maarten> recompiling, IIAMN.

You can't change that without rewriting the code to handle the algorithmic
changes.

The current algorithms are designed to work in an environment where the
clock source is correct to within 500ppm.  If you want a wider range you
will need to do *serious* work on the algorithms and then rewrite the code
to use those new algorithms.

H




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