Re: [netmod] yang-data-ext issues

Juergen Schoenwaelder <j.schoenwaelder@jacobs-university.de> Mon, 23 April 2018 16:51 UTC

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Date: Mon, 23 Apr 2018 18:51:04 +0200
From: Juergen Schoenwaelder <j.schoenwaelder@jacobs-university.de>
To: Ladislav Lhotka <lhotka@nic.cz>
Cc: netmod@ietf.org
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Subject: Re: [netmod] yang-data-ext issues
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On Sun, Apr 22, 2018 at 02:56:51PM +0200, Ladislav Lhotka wrote:

> I am much more concerned with some of the post-1.1 features, also
> because YANG is now being updated in several directions without a
> clear vision. And another big problem is that YANG extensions are
> used for these changes, so we will probably end up with several
> different versions of YANG, although formally everything will be
> 1.1.

I tend to agree. Ideally, we would carefully remove things from YANG
that did not meet the cost/benefit target (e.g., submodules),
reorganize definitions whenever possible (some NETCONF specific stuff
in the YANG specification should not be there, XML encoding may be
factored out) and incorporate new features (like yang-data) after we
have sufficient _experience_ to know that such new features will be
useful (which seems to be the case for yang-data).

Yes, such iterations likely take 2 years at IETF speed but this kind
of maintenance cost/effort is likely the price to be paied for
something that is being used at a larger scale.

Some people will say that the cost of a new language version is high.
(Well, when we did 1.1, some people said it will never be deployed.)
Anyway, not bumping the YANG version number but having instead several
(optional) language extensions is just hiding the version number
change under the carpet.

/js

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