Re: [i2rs] Kathleen Moriarty's No Objection on draft-ietf-i2rs-yang-l3-topology-08: (with COMMENT)

[Martin Bjorklund <[e-mail]>]

Hi,


Xufeng Liu <[e-mail]> wrote:
> Hi Kent,
> 
> > -----Original Message-----
> > From: Kent Watsen [mailto:[e-mail]]
> > Sent: Thursday, February 2, 2017 8:39 PM
> > To: Xufeng Liu <[e-mail]>
> > Cc: [e-mail]; [e-mail]
> > Subject: Re: [i2rs] Kathleen Moriarty's No Objection on
> > draft-ietf-i2rs-yang-l3-
> > topology-08: (with COMMENT)
> > 
> > [reducing distribution]
> > 
> > 
> > Hi Xufeng,
> > 
> > > Assume the following model:
> > >
> > > +--rw nodes
> > >   +--rw node [id]
> > >      +--rw id   string
> > >      +--rw under-lay-attribute-a ???
> > > +---ro nodes-state
> > >   +--ro node [id]
> > >      +--ro id   string
> > >      +--ro attribute-a string
> > >
> > > I cannot define the under-lay-attribute-a to reference attribute-a as:
> > >               type leafref {
> > >                 path "../node/attribute-a"'
> > >               }
> > 
> > 
> > True, but maybe it could be:
> > 
> >    type leafref {
> >       path "../node/attribute-a"
> >       require-instance false;
> >       description
> >         "In the case when the referenced instance is not a configured
> >          object, the system may resolve it by looking for it under the
> >          /nodes-state node.  As the referenced operational state data
> >          may have a lifecycle independent of configuration, this results
> >          in an effect much like pre-provisioning interfaces in RFC 7223.";
> >    }
> [Xufeng] I think that "require-instance false" does not help here. The
> validation for path "../node/attribute-a" still fails because
> "attribute-a" does not exist under /nodes/node/.

No, "require-instance false" essentially turns off validation.  Section
9.9.3 in RFC 7950 says:

   If "require-instance" is "false", it means that the instance being
   referred to MAY exist in valid data.


/martin