[ntp:questions] NTP, no external time source, peering "Undisciplined Local Clocks" ?
brad at stop.mail-abuse.org
Wed Oct 19 11:36:49 UTC 2005
At 4:19 PM +0200 2005-10-18, Marco Molteni wrote:
> Can I configure A,B,C to peer with each other in a meshed fashion, so
> to have each clock influenced by all the others?
Okay, let's analyze this a bit. You've got three guys on a
desert island, and they each have wristwatches. But no one knows
whose watch is more accurate. What time is it and how do you choose?
The answer is that you either choose arbitrarily, or you can't
choose. At least, not with the NTP algorithms.
The concept of NTP is to have an external source of "The One True
Time", and to always try to work to get your clock to more closely
agree with that. There are plenty of algorithms for doing that, but
everything operates on the fundamental assumption that everyone has
the same goal, that of always trying to move closer to "The One True
When you violate that most basic assumption, everything else goes
out the window.
I don't think that NTP is the right solution here.
Brad Knowles, <brad at stop.mail-abuse.org>
"Those who would give up essential Liberty, to purchase a little
temporary Safety, deserve neither Liberty nor Safety."
-- Benjamin Franklin (1706-1790), reply of the Pennsylvania
Assembly to the Governor, November 11, 1755
SAGE member since 1995. See <http://www.sage.org/> for more info.
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