Subject: Re: [netmod] Fwd: Multiple deviations with same target

From: Juergen Schoenwaelder <[email-masked]>
Date: Thu, 28 Apr 2016 21:15:06 +0200

On Mon, Mar 07, 2016 at 11:26:36AM +0100, Juergen Schoenwaelder wrote:
> On Tue, Feb 16, 2016 at 12:42:27PM +0100, Juergen Schoenwaelder wrote:
> >   So perhaps the proposal is to add
> > 
> >     After applying all deviations announced by a server, in any order,
> >     the resulting data model MUST still be valid.
> > 
> >   just before the beginning of section 7.20.3.1?
> 
> I like to see whether we have consensus to add this clarifying
> sentence. I believe it documents something that we always assumed to
> be true but we did not write it down explicitly. If anyone disagrees
> with adding this clarification, please speak up now.
>

I have not heard anyone disagreeing with adding this clarification.

Martin did not put this additional sentence into -12 and since we seem
to have consensus on adding this clarification I like to ask him to
add this sentence if another revision is made before the IESG
telechat. I am CCing Benoit in case he wants to add this as a comment
to his IESG evaluation record.

/js

-- 
Juergen Schoenwaelder           Jacobs University Bremen gGmbH
Phone: +49 421 200 3587         Campus Ring 1 | 28759 Bremen | Germany
Fax:   +49 421 200 3103         <http://www.jacobs-university.de/>

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From: Andy Bierman <[email-masked]>
Date: Thu, 28 Apr 2016 21:09:40 -0700

> to his IESG evaluation record.
Was it unclear before that the result of deviations were allowed to be
invalid?
I do not object to this text, but I hope those 3 words "in any order" are
enough
of a clue to developers that on the server "only one wins" but the client
does not know which one.  I will add a YANG guideline to avoid duplicate
deviation targets.  (issue #33)

/js

Andy

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> [email-masked]
> https://www.ietf.org/mailman/listinfo/netmod
>

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From: Benoit Claise <[email-masked]>
Date: Fri, 29 Apr 2016 09:49:24 +0200

> to his IESG evaluation record.
Thanks. We're at IETF last call statge, so there is still time to 
include this change.

Regards, B.

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From: Ladislav Lhotka <[email-masked]>
Date: Fri, 29 Apr 2016 10:18:15 +0200

> Was it unclear before that the result of deviations were allowed to be

Right, I think it goes pretty much without saying, so this sentence is
IMO unnecessary. The real problem is that different ways of applying the
deviations may lead to different data models, all valid.

I think this should be avoided although I don't know how to do it. In
hindsight, it would probably be better to allow the server to specify
just a single deviation module with no other content. Then it would be
easier to state some rules.

> deviation targets.  (issue #33)

I don't think it is clear that only one wins. Three deviations adding
default values to the same leaf-list target could be possibly applied
together.

Lada

-- 
Ladislav Lhotka, CZ.NIC Labs
PGP Key ID: E74E8C0C

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From: Juergen Schoenwaelder <[email-masked]>
Date: Fri, 29 Apr 2016 11:27:05 +0200

On Fri, Apr 29, 2016 at 10:18:15AM +0200, Ladislav Lhotka wrote:
> IMO unnecessary.

Apparently, this was not clear to every reader and hence the proposal
to add this sentence in order to make this explicit.

/js

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From: Ladislav Lhotka <[email-masked]>
Date: Fri, 29 Apr 2016 11:59:20 +0200

> On 29 Apr 2016, at 11:27, Juergen Schoenwaelder <[email-masked]> wrote:
> 

It's just hand-waving, and has little to do with the subject of this thread.

Lada

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From: Benoit Claise <[email-masked]>
Date: Fri, 29 Apr 2016 12:01:38 +0200

> to add this sentence in order to make this explicit.
This is a always a good principle IMO.

Regards, Benoit