Re: [Ntp] Éric Vyncke's No Objection on draft-ietf-ntp-interleaved-modes-05: (with COMMENT)

Miroslav Lichvar <mlichvar@redhat.com> Mon, 28 June 2021 14:12 UTC

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Date: Mon, 28 Jun 2021 16:11:58 +0200
From: Miroslav Lichvar <mlichvar@redhat.com>
To: =?iso-8859-1?Q?=C9ric?= Vyncke <evyncke@cisco.com>
Cc: The IESG <iesg@ietf.org>, draft-ietf-ntp-interleaved-modes@ietf.org, ntp-chairs@ietf.org, ntp@ietf.org, odonoghue@isoc.org
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Subject: Re: [Ntp] =?iso-8859-1?q?=C9ric_Vyncke=27s_No_Objection_on_draft-iet?= =?iso-8859-1?q?f-ntp-interleaved-modes-05=3A_=28with_COMMENT=29?=
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On Mon, Jun 28, 2021 at 04:07:51AM -0700, Éric Vyncke via Datatracker wrote:
> Éric Vyncke has entered the following ballot position for
> draft-ietf-ntp-interleaved-modes-05: No Objection

Thanks for the review.

> -- Section 2 --
> "  The server MAY separate the timestamps
>    by IP addresses, but it SHOULD NOT separate them by port numbers,
>    i.e.  clients are allowed to change their source port between
>    requests."
> With draft-ietf-ntp-port-randomization in mind, please change the "clients are
> allowed" into "clients are recommended to"

If I didn't miss an update in the recent changes of the draft, the
port-randomization draft still leaves that per-request or
per-association decision to the implementation with no preference, so
I think they can but are not recommended to change the port between
requests.

> "  Both servers and clients that support the interleaved mode MUST NOT
>    send a packet that has a transmit timestamp equal to the receive
>    timestamp"
> Will it always be possible to comply with the above "MUST NOT" ?

I think it will. If the timestamps happen to be equal, one of the
timestamps can simply be adjusted by 1 before the transmission. That's
~1/4 of nanosecond, well hidden in the typical precision of an NTP
clock.

-- 
Miroslav Lichvar