Subject: [Extra] Opsdir last call review of draft-ietf-extra-sieve-fcc-08

From: Dan Romascanu <[email-masked]>
Date: Wed, 09 Jan 2019 01:30:22 -0800

Reviewer: Dan Romascanu
Review result: Has Issues

The document extends the Sieve Email Filtering Language [RFC5228] by providing
a number of action commands, some of which can generate additional messages of
behalf of the user. It is a clear document, its target being developers and
users of the protocol. I liked the fact that the authors included a
'Compatibility with Other Actions' section that describes the interoperability
with existing deployed versions of the protocol, as well as the inclusion of a
temporary section about Implementation Status. I am missing however some
information about possible impact of the new action commands on deployment and
operations on servers already in operation. I assume that scalability and
compatibility between older and newer versions (including or not the new
defined commands) were assessed, but this is not documented. Some confirmation,
warnings (if any) and useful information that operators should know at
deployment would be useful. I suggest that you consider adding such a paragraph
or short section.

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From: Alexey Melnikov <[email-masked]>
Date: Wed, 09 Jan 2019 11:05:13 +0000

Hi Dan,
Thank you for your review.

On Wed, Jan 9, 2019, at 9:30 AM, Dan Romascanu wrote:
> defined commands) were assessed, but this is not documented.

As :fcc is controlled by Sieve extension mechanism, Sieve scripts need to be updated before :fcc can be used. This means that either users need to manually update scripts and/or implementations that would use :fcc automatically need to be updated.
So older (nonextended) implementations are not affected by this extension.

Does this help or did I miss the point you are trying to convey?

Thank you,
Alexey

> Some confirmation,

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From: Dan Romascanu <[email-masked]>
Date: Wed, 9 Jan 2019 13:27:34 +0200

Hi Alexey,

Thanks for the answer. It helps indeed. It would help better if this is
documented with one paragraph in the text of the document. While developers
know well the details, users and operators may be less familiar with these.

Regards,

Dan

On Wed, Jan 9, 2019 at 1:05 PM Alexey Melnikov <[email-masked]>
wrote:

> As :fcc is controlled by Sieve extension mechanism, Sieve scripts need to
> be updated before :fcc can be used. This means that either users need to
> manually update scripts and/or implementations that would use :fcc
> automatically need to be updated.

---

From: Ned Freed <[email-masked]>
Date: Wed, 09 Jan 2019 07:58:32 -0800 (PST)

> know well the details, users and operators may be less familiar with these.

I'm going to push back on this a bit. It's effectively axiomatic that in order
to understand a protocol extension you first need to understand the protocol
and it's extension mechanism. Having every extension reiterate a subset of how
the extension mechanism works seems pointless at best and more likely
counterproductive - covering only a subset of the mechanism, which is
all you're be able to do without repeating a significant amount of
RFC 5228 will give the (incorrect) impression that it's all you need to know.

Now, it would be one thing if there was a section in RFC 5228 that
describes the extension mechanism - if that were the case we could
just reference it. But for better or worse RFC 5228 isn't constructed that
way. Perhaps more than any other protocol, Sieve is designed to be extended
easily, and the discussion of how that works appears throughout the
document.

Finally, if we're going to talk about implementation and use issues in regards
to this extension - and I'm not saying we should - such text would be better
spent on discussing the interplay between this extension and where sieves are
evaluated.

				Ned

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From: Dan Romascanu <[email-masked]>
Date: Wed, 9 Jan 2019 18:55:58 +0200

Hi Ned,

Thanks for your answer. I am leaving to the OPS ADs the judgment about how
important the clarification text would be. The OPS-DIR reviews are written
to help them in their evaluaton tasks.

Regards,

Dan