On Fri, Aug 25, 2017 at 10:56 AM, Kent Watsen <[email protected]> wrote:

>
> I have the same preference.  The suggested text doesn't seem to provide
> actual modeling recommendations.  Aren't there details beyond how or when
> a module transitions to NMDA that should be mentioned?  For instance, the
> text doesn't say anything about how to best locate config false nodes, or
> how to handle the case when the value-space for a node's configured and
> operational values differ.  Is the plan then to remove this section
> entirely once the NMDA-transition is complete?
>
>

Obviously NMDA cannot be used for objects where the configuration value set
and the operstate value set differ, such as with the interface
admin-status/oper-status.
Do you want a sentence added that says to use config false leafs as needed
within the
configuration entry? A sentence that says operational data is embedded in
the
configuration entry?



> As I recall, the main reason why we are not progressing the guidelines
> draft is because we didn't want the short-term text in an RFC.  Putting
> essentially the same text into another RFC seems inconsistent.  But,
> if this is what people want, I suppose it's better to churn this document
> than to introduce a distinct "guidelines" RFC...


6087bis was supposed to be a minor update, not a living draft that doubles
as a YANG tutorial and ongoing issues list.



>
>
K.  // contributor
>
>
>
Andy


> --
>
> My preference is to have the guidelines say what people should do,
> namely design NMDA models. I would prefer to keep any transition
> aspects out of the guidelines. If people want to include transition
> aspects, it should be in the appendix (i.e., easy to remove / ignore
> later on).
>
> I understand that there is a timing issue. The question is what you
> mean with "NMDA solution makes it to publication (request)". If you
> mean the core NMDA document, this is pretty much in reach and keeping
> this guidelines document on hold until then may be an option. If you
> mean the complete solution set, including model updates and moving the
> protocol extensions in NETCONF to publication request, then this may
> take a bit more time.
>
> /js
>
> On Tue, Aug 22, 2017 at 04:32:14PM -0400, Lou Berger wrote:
> > Kent/WG,
> >
> >     This seems a bit terse to me and not provide needed guidance during
> > the current transition period.  I understood  the discussion ended up
> > with the options being to either (1) provide the guidance as a
> > standalone document, e.g., (a)-(s) in draft-dsdt-nmda-guidelines, with a
> > pointer to it from 6087bis or (2) just move those sections to 6087 bis.
> > Either way, we'll need a new bis once the full NMDA solution makes it to
> > publication (request).
> >
> > I thought the plan was to do (s).  If so, we need the full text.
> > Looking at the current repo
> > (https://github.com/netmod-wg/datastore-dt/blob/master/
> guidelines/guidelines.txt)
> > it would be:
> >
> >     4.23 Operational Data
> >
> >     The following guidelines are meant to help modelers develop
> >     YANG models that will maximize the utility of the model with
> >     both current implementations and NMDA-capable implementations
> >     [draft-ietf-netmod-revised-datastores].
> >
> >     (a) New models and models that are not concerned with the
> >     operational state of configuration information SHOULD
> >     immediately be structured to be NMDA-compatible.
> >
> >     (b) Models that require immediate support for "in use" and
> >     "system created" information SHOULD be structured for NMDA.  A
> >     non-NMDA version of these models SHOULD exist, either an
> >     existing model or a model created either by hand or with
> >     suitable tools that mirror the current modeling strategies.
> >     Both the NMDA and the non-NMDA modules SHOULD be published in
> >     the same document, with NMDA modules in the document main body
> >     and the non-NMDA modules in a non-normative appendix.  The use
> >     of the non-NMDA model will allow temporary bridging of the
> >     time period until NMDA implementations are available.
> >
> >     (c) For published models, the model should be republished with
> >     an NMDA-compatible structure, deprecating non-NMDA constructs.
> >     For example, the "ietf-interfaces" model in ^RFC7223^ will be
> >     restructured as an NMDA-compatible model.  The
> >     "/interfaces-state" hierarchy will be marked "status
> >     deprecated".  Models that mark their "/foo-state" hierarchy
> >     with "status deprecated" will allow NMDA-capable
> >     implementations to avoid the cost of duplicating the state
> >     nodes, while enabling non-NMDA-capable implementations to
> >     utilize them for access to the operational values.
> >
> >     (d) For models that augment models which have not been
> >     structured with the NMDA, the modeler will have to consider
> >     the structure of the base model and the guidelines listed
> >     above.  Where possible, such models should move to new
> >     revisions of the base model that are NMDA-compatible.  When
> >     that is not possible, augmenting "state" containers SHOULD be
> >     avoided, with the expectation that the base model will be
> >     re-released with the state containers marked as deprecated.
> >     It is RECOMMENDED to augment only the "/foo" hierarchy of the
> >     base model.  Where this recommendation cannot be followed,
> >     then any new "state" elements SHOULD be included in their own
> >     module.
> >
> >     To create the temporary non-NMDA model from an NMDA model, the
> >     following steps can be taken:
> >
> >     - Rename the module name by postpending "-state" to the
> >       original module's name
> >     - Change the namespace by postpending "-state" to the original
> >       namespace value
> >     - Change the prefix by postpending "-s" to the original prefix
> >       value
> >     - Set all top-level nodes to have a "config" statement of
> >       value "false"
> >     - add an import to the original module (e.g., for typedef
> >       definitions)
> >     - modify any imports, used for leafrefs or identityrefs, to
> >       import the -state version of the module
> >     - remove any 'typedef' or 'identity' definitions
> >     - prefix any uses of the typedefs and identities accordingly
> >     - update leafref and augment paths to use the new "-s" prefix
> >
> > For me (with any/all hats) the key downside is that we'll need to  rev
> > this text (again) in the not too distant future, but that we don't have
> > an alternative as LC on the full solution is still a bit away.
> >
> > What do people think?
> >
> > Lou
> >
> >
> > On 8/22/2017 3:53 PM, Kent Watsen wrote:
> > > Hi,
> > >
> > > During the meeting in Chicago, the NMDA authors took an action to
> > > propose some text for S4.23.  After a little review, the following
> > > emerged.  Yes, it's short, but was anything left anything out?
> > >
> > >
> > > =====START=====
> > >
> > > 4.23 Operational Data
> > >
> > > Operational data includes both config "false" nodes as well as,
> > > on servers supporting <operational> [draft-ietf-netmod-revised-
> datastores],
> > > the applied value of config "true" nodes.
> > >
> > > YANG modules SHOULD be designed assuming they will be used on
> > > servers supporting <operational>.  With this in mind, YANG
> > > modules SHOULD define config "false" wherever they make sense
> > > to the data model.  Config "false" nodes SHOULD NOT be defined
> > > to provide the operational value for configuration nodes,
> > > except when the value space of a configured and operational
> > > values may differ, in which case a distinct config "false"
> > > node SHOULD be defined to hold the operational value for the
> > > configured node.
> > >
> > > =====STOP=====
> > >
> > >
> > > One question that came up is if "operational data" is a well-defined
> > > term.  This string appears 10 times in rfc6087bis.  Most interestingly,
> > > appendix Section A.8. (v05 to v06) includes this line item:
> > >
> > >     Changed term "operational state" to "operational data"
> > >
> > > So it seems to be deliberate...
> > >
> > >
> > > Kent  // contributor
> > >
> > >
> > >
> > > _______________________________________________
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> > > https://www.ietf.org/mailman/listinfo/netmod
> > >
> >
> > _______________________________________________
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>
> --
> Juergen Schoenwaelder           Jacobs University Bremen gGmbH
> Phone: +49 421 200 3587         Campus Ring 1 | 28759 Bremen | Germany
> Fax:   +49 421 200 3103         <http://www.jacobs-university.de/>
>
>
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