Subject: Re: [netmod] 2 more data types (!)

From: Juergen Schoenwaelder <[email-masked]>
Date: Sun, 1 Feb 2009 14:09:08 +0100

On Sat, Jan 31, 2009 at 01:46:14PM -0800, Andy Bierman wrote:

> I know this would be a significant change,
> so it is OK if we handle it with extensions
> until later.
>
>   1) qname
>   2) xpath
>
> Both of these data types are special because of their content:
>   1) the manager must provide xmlns decls for the YANG prefixes
>   2) the agent must match xmlns decls to YANG namespaces
>
> The data type 'instance-identifier' is already covered,
> but it would be on this special list as well.

My idea was to add a typedef for a type called xpath to yang-types.
Since an xpath type has already shown up in YANG modules, I suppose
this is useful to have. I have not seen a qname in a YANG module yet
but adding a definition of a qname type to yang-types should not be
too difficult either.

Or was your proposal to add these types to the builtin types? This
would be a bigger surgery and it is not obvious why these types should
be builtin types. Perhaps you can clarify what you wanted to propose.

/js

-- 
Juergen Schoenwaelder           Jacobs University Bremen gGmbH
Phone: +49 421 200 3587         Campus Ring 1, 28759 Bremen, Germany
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From: Andy Bierman <[email-masked]>
Date: Sun, 01 Feb 2009 09:02:46 -0800

> be builtin types. Perhaps you can clarify what you wanted to propose.

I was thinking built-in types,
but I think the yang-types draft would be fine.

> /js

Andy

---

From: Martin Bjorklund <[email-masked]>
Date: Wed, 04 Feb 2009 07:53:07 +0100 (CET)

Juergen Schoenwaelder <[email-masked]> wrote:
> this is useful to have. 

I agree, and I think ietf-yang-types (name?) is the correct module to
add them to.

> I have not seen a qname in a YANG module yet

I think we should stick to the idea of being conservative in what we
add.

FWIW, we support this type in our DML, but I haven't seen anyone using
it.

/martin

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From: Juergen Schoenwaelder <[email-masked]>
Date: Wed, 4 Feb 2009 11:48:37 +0100

On Wed, Feb 04, 2009 at 07:53:07AM +0100, Martin Bjorklund wrote:
 
> > I have not seen a qname in a YANG module yet but adding a
> > definition of a qname type to yang-types should not be too
> > difficult either.
> 

Andy's YANG model for NETCONF uses qnames for things such as
bad-attribute, bad-element, ok-element, err-element, and 
noop-element. Can you check whether you agree these are qnames?
If you do agree, then it might be a reason to add a qname type.

And yes, it is likely that YANG modules using qname and xpath types
are going to define NETCONF extensions (e.g., definition of new
protocol operations) while normal data models may not need these types
so much.

/js

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From: Martin Bjorklund <[email-masked]>
Date: Wed, 04 Feb 2009 12:14:08 +0100 (CET)

> noop-element. Can you check whether you agree these are qnames?

Yes, they are QNames.

However, I have argued in the past that the ok-, err-, and
noop-elements are not very useful (see
http://ops.ietf.org/lists/netconf/netconf.2006/msg00115.html)

> protocol operations) while normal data models may not need these types

Yes.

/martin

---

From: Andy Bierman <[email-masked]>
Date: Thu, 05 Feb 2009 18:19:23 -0800

> If you do agree, then it might be a reason to add a qname type.

HTML:
http://www.netconfcentral.org/modules/xsd/2007-12-06

YANG:
http://www.netconfcentral.org/src/xsd_2007-12-06.yang

This is the 'work-in-progress' xsd.yang that I wrote awhile back.
It needs some 'pattern and XSD expert' to finish off some of
the string types.  Not sure if you want to cherry-pick,
ignore, or consider a a standard xsd.yang module.
It's not very important, considering the current status of XSD
within the WG.  But if there are some types that might get
replicated over and over, then it could be worth it.

Andy

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From: David Partain <[email-masked]>
Date: Wed, 11 Feb 2009 13:21:54 +0100

Hi,

> > protocol operations) while normal data models may not need these types

I think that putting an xpath type in the yang-types draft is fine.  I 
personally don't see any consensus on whether to move forward with a qname 
type or not.

David

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From: Juergen Schoenwaelder <[email-masked]>
Date: Wed, 11 Feb 2009 13:57:17 +0100

> personally don't see any consensus on whether to move forward with a qname 

I agree.

/js