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[Ntp] Re: [EXT] Re: Paul Wouters' No Objection on draft-ietf-ntp-interleaved-modes-07: (with COMMENT)

"Windl, Ulrich" <u.windl@ukr.de> Fri, 23 August 2024 05:53 UTC

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From: "Windl, Ulrich" <u.windl@ukr.de>
To: Miroslav Lichvar <mlichvar@redhat.com>, Paul Wouters <paul.wouters@aiven.io>
Thread-Topic: [EXT] [Ntp] Re: Paul Wouters' No Objection on draft-ietf-ntp-interleaved-modes-07: (with COMMENT)
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Date: Fri, 23 Aug 2024 05:53:42 +0000
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Subject: [Ntp] Re: [EXT] Re: Paul Wouters' No Objection on draft-ietf-ntp-interleaved-modes-07: (with COMMENT)
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> -----Original Message-----
> From: Miroslav Lichvar <mlichvar@redhat.com>
> Sent: Thursday, August 22, 2024 4:11 PM
> To: Paul Wouters <paul.wouters@aiven.io>
> Cc: The IESG <iesg@ietf.org>; draft-ietf-ntp-interleaved-modes@ietf.org;
> ntp-chairs@ietf.org; ntp@ietf.org; odonoghue@isoc.org
> Subject: [EXT] [Ntp] Re: Paul Wouters' No Objection on draft-ietf-ntp-
> interleaved-modes-07: (with COMMENT)
> 

[Windl, Ulrich] 
[...]

> If the server separates timestamps by IP address and there are
> multiple clients on one IP address using similar polling intervals,
> yes, the interleaved mode will not work. That's expected. The protocol
> will fall back to the basic mode. The same thing can happen when the
> server has too many clients. There is no guarantee the client will
> receive an interleaved response, ever.

[Windl, Ulrich] 

There is (or at least was) a problem with the reference/standard implementation:
If  a client uses a combination of a few statically configured servers/peers and some auto-detection like manycast,
Then one server could be configured twice (one static, one dynamic). I think the standard algorithm did not explicitly forbid that, so...
Things may be even worse if the server is multi-homes, and can be reached through different paths from the client (that is also multi-homed.

Regards,
Ulrich

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