[Ntp] Antw: Re: Antw: Re: Antw: [EXT] NTPv5 Loop Detection without Stratum

[Ulrich Windl <[e-mail]>]

>>> Miroslav Lichvar <[e-mail]> schrieb am 31.08.2022 um 09:25 in
Nachricht <Yw8NBX6ATjRr0/A4@localhost>:
> On Tue, Aug 30, 2022 at 01:51:43PM ‑0700, Hal Murray wrote:
>> That brings up an interesting point.
>> 
>> What does loop mean?
> 
> I think it's when a clock is synchronizing directly or indirectly
> (over one or more other clocks) to itself. As a test, you can inject a
> small offset to the server's clock and see if the impulse comes back
> later from one of its sources.

I think that is not sufficient: It would be a loop if the server's clock
(actually the error estimate) gets worse again, and then the process continues
(clock is getting more inaccurate over time). However it it's "smoothed out"
it's not a loop IMHO.

> 
> In the graph theory, it's a loop in a directed graph.

The problem is the "line" (correpsonding to time): In NTP it's a combination
of several sources (lines).

[...]

Regards,
Ulrich