Re: [netmod] WG Last Call: draft-ietf-netmod-revised-datastores-04 updates

["t.petch" <[e-mail]>]

----- Original Message -----
From: "Martin Bjorklund" <[e-mail]>
Sent: Monday, September 18, 2017 8:58 AM


> "t.petch" <[e-mail]> wrote:
> > ----- Original Message -----
> > From: "Martin Bjorklund" <[e-mail]>
> > Sent: Sunday, September 17, 2017 2:41 PM
> >
> > > Andy Bierman <[e-mail]> wrote:
> > > > On Sat, Sep 16, 2017 at 12:24 AM, Juergen Schoenwaelder <
> > > > [e-mail]> wrote:
> > > >
> > > > > On Fri, Sep 15, 2017 at 02:07:58PM -0700, Andy Bierman wrote:
> > > > > > Hi,
> > > > > >
> > > > > > I strongly agree with Tom that the current draft is an
update to
> > RFC
> > > > > 7950.
> > > > > > I also strongly disagree with the decision to omit RFC 2119
in a
> > > > > standards
> > > > > > track document. IMO RFC 2119 terms need to be used in
normative
> > text,
> > > > > > especially when dealing with XPath and YANG compiler
behavior.
> > > > > >
> > > > >
> > > > > RFC 8174:
> > > > >
> > > > >    o  These words can be used as defined here, but using them
is
> > not
> > > > >       required.  Specifically, normative text does not require
the
> > use
> > > > >       of these key words.  They are used for clarity and
> > consistency
> > > > >       when that is what's wanted, but a lot of normative text
does
> > not
> > > > >       use them and is still normative.
> > > > >
> > > > >
> > > > So what?
> > > > Existing YANG specifications use RFC 2119 terms.
> > > > This draft uses those terms, just with lower-case.
> > >
> > > Actually, section 5.1 XPath Context in the revised datastore draft
> > > uses the same language as section 6.4.1 XPath Context in RFC 7950.
In
> > > fact, the text in the draft is copied (and adjusted) from RFC
7950.
> >
> > Martin
> >
> > 'Adjusted' might be seen as a weasel word:-)
> >
> >    If the XPath expression is defined in a substatement to a
> >       "notification" statement, the accessible tree is the
notification
> >       instance, all state data in the server, and the running
> >       configuration datastore.
> >
> > becomes
> >
> > If the XPath expression is defined in a substatement to a
> >       "notification" statement, the accessible tree is the
notification
> >       instance and all operational state in the server.
> >
> > Goodbye <running> (well, running configuration in RFC7950).  Is it a
> > material difference? - it will take me a while to work that one out.
>
> The difference is that the xpath expressions no longer sees unused
> configuration in running.  But if the config is used, it exists in
> <operational> under the same path as before, and it is available.
>
> > I focussed on the XPath rules because they seemed the clearest case,
but
> > updating the definitions, and saying this section will replace the
> > definitions in [RFC6241] and [RFC7950] when these documents are
revised
> > seems .... well, like an Erratum held for Update i.e. another
Updates.
>
> Are you saying that this is an argument for having "Updates: 7950"?

Yes

Tom Petch

>
> /martin