Re: [netmod] new YANG 1.1 Issue Y61: I2RS support

[Andy Bierman <[e-mail]>]

On Mon, Aug 3, 2015 at 7:48 AM, Ladislav Lhotka <[e-mail]> wrote:

>
> > On 03 Aug 2015, at 16:41, Andy Bierman <[e-mail]> wrote:
> >
> >
> >
> > On Mon, Aug 3, 2015 at 2:25 AM, Juergen Schoenwaelder <
> [e-mail]> wrote:
> > On Mon, Aug 03, 2015 at 11:06:41AM +0200, Jernej Tuljak wrote:
> > > Juergen Schoenwaelder je 3.8.2015 ob 10:18 napisal:
> > > >Any description statement in principle can do this. We trust that sane
> > > >data model writers won't do bad things. And if they do, we hope that
> > > >people will not implement and deploy bad things.
> > >
> > > Why not simply make this impossible by ensuring that description
> > > statements cannot change what has already been agreed upon in RFC6020
> > > (aka YANG semantics)? I would have no problem with descriptions being
> > > normative, if this would be the case.
> >
> > You need to define way more clearly what 'YANG semantics' means.
> >
> >
> >
> > Agreed.  The description-stmt is normative.
> > It defines implementation requirements for a data node.
> > It is not used to override other YANG statements.
> > However, if the description says "child foo must be
> > greater than the value of bar" that is just as normative
> > as a must-stmt that says the same thing.
> >
> >
> > > >I continue to see extension statements as reusable and (in principle)
> > > >machine readable fragments of description statements. From this
> > > >perspective, it seems odd to make a difference between extensions and
> > > >description statements.
> > >
> > > I still disagree that description statements should be more powerful
> > > than any other YANG statement.
> >
> > What does 'powerful' mean? Time that someone writes concrete text so
> > we can have a more constructive discussion.
> >
> >
> > A YANG description-stmt cannot override the syntax and semantics of
> other YANG
> > statements.  But is is mandatory and it is normative.
>
> It’s not only about overriding. For example, it wouldn’t be good to
> introduce a new data node type though an extension.
>
>
But isn't that exactly what you are proposing by making ephemeral data
an extension instead of part of YANG?

None of the existing text covers the validation rules for ephemeral data.
Nothing is needed for config=true nodes in the ephemeral datastore,
but ephemeral-only data needs to be identified.

Validation rules are needed for ephemeral data.
Whether this is part of a protocol spec or YANG needs to be decided.




> Lada
>
>
Andy


> >
> >
> >
> >
> > /js
> >
> >
> > Andy
> >
> >
> > --
> > Juergen Schoenwaelder           Jacobs University Bremen gGmbH
> > Phone: [phone]         Campus Ring 1 | 28759 Bremen | Germany
> > Fax:   [phone]         <http://www.jacobs-university.de/>
> >
>
> --
> Ladislav Lhotka, CZ.NIC Labs
> PGP Key ID: E74E8C0C
>
>
>
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