Hi,
So after the various meetings and discussions this week, I think that
the most important thing for IETF to do is to publish reviewed YANG
models quickly, with the understanding that it is better to publish
imperfect models than to end up not publishing any models at all. This
is with the understanding that these models could be fixed by subsequent
RFCs if required.
So, I effectively support Acee's solution (2). But to state this more
precisely, I would suggest that the specific guidance should be:
1) IETF Models MUST NOT have a split for applied configuration leaves.
All IETF models that have not been turned into RFCs must be modified to
remove any applied configuration nodes. Any models that have this
convention in RFCs should be revised to follow a consistent
intended/applied convention for IETF models. [The justification here is
that IETF standard models have to be able to assume that the applied
configuration will be available via a separate applied configuration (or
operational state) datastore or equivalent mechanism.]
2) All IETF Models MUST put "derived state and statistics" into a
separate namespace from the configuration (i.e. top level "feature" and
"feature-state"). The two trees must be as structurally similar as
possible, sharing the same paths, node names (except the top level
node), using the same lists keys where appropriate, etc.*
3) Both of these rules should be written into rfc6087bis. We should
then get this guidelines document finished as quickly as possible at the
highest priority, and use that as the definitive guideline for the
modules that the working groups are working on.
* Note, I chose this option not because I think that it is elegant
(because I don't) but because it seems to me that it is the only
pragmatically option that we have available. The alternatives appear to
be: (i) we wait another year before publishing any models (if ever), or
(ii) we publish models that no-one can use today without violating the
existing RFCs, or (iii) we end up with a hybrid mess without any
consistency.
Thanks,
Rob
On 11/07/2016 18:36, Acee Lindem (acee) wrote:
While there are details to be worked out between the two data stores
models (as indicated below), we now have implicit modeling of applied
configuration. Existing models (both standard and draft) do not take this
into consideration and, consequently, much of the state that is modeled
explicitly represents the application configuration. For the RFC models,
it probably doesn’t make much sense to redo them (unless they are being
reworked for other reasons). This still leaves the existing WG draft
models for which we have basically 3 options:
1. Do nothing - allow them proceed as they are with multiple ways of
representing the applied configuration. This would provide visibility to
the data independent of whether or not the device supported the revised
data-stores supporting implicit retrieval of the applied configuration.
2. Prune out the redundant data nodes except those required as list
keys, etc, since they can be obtained from the applied state data store.
3. #2 plus collapse the config (read-write) and system-state
(read-only) into common containers. No more branching of
<model-name>-config and <model-name>-state at the top level of the model.
At I high-level, I feel these are the options. I’m not married to any one
of these and the worse thing we could do is hold up progression of the
existing YANG model drafts for another couple years while we debate the
best course. Having said that, #3 is compelling since it will yield the
most concise models and colocates the schema data nodes for any managed
object.
Thanks,
Acee
On 7/1/16, 12:36 PM, "netmod on behalf of Lou Berger"
<netmod-boun...@ietf.org on behalf of lber...@labn.net> wrote:
All,
It's time to make a consensus call on this topic, so that we can all move
on to defining a solution and aligning modules under development. Based
on the feedback received and the overall discussions on the topic, we see
that there is consensus to follow a datastore based approach to
supporting operational state, i.e., direction 'B'.
We will be asking the authors of [4] and [5] to review their proposals
(individual drafts) in Berlin, as well as to highlight differences and
suggest ways that their work could be consolidated. Of course, others may
also choose to submit their own proposals. Given the importance of this
work, we will be looking to have active discussion on the topic both in
Berlin and on the list, with an objective of having a draft ready for
considerations as a WG document by the November IETF.
We have reviewed this decision with our AD and the NetConf chairs and
have agreed to begin this work in NetMod. We certainly expect to
coordinate the work with the NetConf WG and re-home work as/if needed.
Finally, we'd also like to thank all those who have contributed to this
discussion to date, from problem identification to proposed solutions,
and we look forward to your continued efforts to publish a standard
solution.
Lou (and Kent)
On 6/7/2016 10:19 AM, Lou Berger wrote:
All,
We want to provide an update based on the off line discussions
related to OpState Solutions that we have been having and solicit
input from the WG.
All authors of current solution drafts [1,2,3] together with those
who helped conduct the solutions analysis* were invited to the these
discussions -- with the objective of coming up with a single
consolidated proposal to bring to the WG. (I/Lou acted as facilitator
as Kent and Juergen were and are involved with the technical details.)
The discussions have yielded some results but, unfortunately,
not a single consolidated proposal as hoped, but rather two
alternate directions -- and clearly we need to choose one:
1) Adopt the conventions for representing state/config
based on Section 6 of [1].
From a model definition perspective, these conventions
impact every model and every model writer.
2) Model OpState using a revised logical datastore definition
as introduced in [4] and also covered in [5]. There is
also a variant of this that we believe doesn't significantly
impact this choice.
With this approach, model definitions need no explicit
changes to support applied configuration.
>From a technology/WG standpoint, we believe an approach
that doesn't impact every model written (i.e., #2) is superior.
The counterpoint to this is that the conventions based
approach (i.e., #1) is available today and being followed in
OpenConfig defined models.
We would like to hear opinions on this from the WG before
declaring one of the following as the WG direction:
A) models that wish to support applied configuration MUST
follow conventions based on [1] -- and the WG needs to
formalize these conventions.
or
B) no explicit support is required for models to support
applied configuration -- and that the WG needs to
formalize an opstate solution based on the approach
discussed in [4] and [5].
We intend to close on this choice before Berlin.
Thank you,
Lou (and co-chairs)
[1] https://tools.ietf.org/html/draft-openconfig-netmod-opstate-01
[2] https://tools.ietf.org/html/draft-kwatsen-netmod-opstate-02
[3] https://tools.ietf.org/html/draft-wilton-netmod-opstate-yang-02
[4]
https://tools.ietf.org/html/draft-schoenw-netmod-revised-datastores-00
[5]
https://tools.ietf.org/html/draft-wilton-netmod-refined-datastores-00
* - Chris H. and Acee L.
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