[ntp:questions] Asymmetric Delay and NTP

Joe Gwinn joegwinn at comcast.net
Sun Mar 16 23:55:18 UTC 2014


In article <lg5bug$682$1 at dont-email.me>, David Woolley
<david at ex.djwhome.demon.invalid> wrote:

> On 16/03/14 22:16, Joe Gwinn wrote:
> > I recall seeing something from Dr. Mills saying that a formal proof had
> > been found showing that no packet-exchange protocol (like NTP) could
> > tell delay asymmetry from clock offset.  Can anyone provide a reference
> > to this proof?
> 
> I would have thought it was obvious.

It was generally believed that this was true, but what was lacking was
the mathematical proof that no message-exchange protocol, however
clever, could overcome delay asymmetry.  I recall that someone finally
found a proof.

Joe Gwinn



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