Re: [netmod] OpsState Direction Impact on Recommended IETF YANG Model Structure

["Acee Lindem (acee)" <[e-mail]>]

On 7/14/16, 4:00 PM, "Kent Watsen" <[e-mail]> wrote:

>
>[This thread took on a life of its own, so I’m replying to this email
>from two days ago]
>
>I had assumed the plan/recommendation would be:
>  - for works-in-progress, to evaluate if their models can be improved.
>  - for existing RFCs, do nothing (though we may want to consider
>RFC7223).
>
>By “if their models can be improved” in the above, I’m implying that
>having a top-level -state branch may still be the best solution for some
>models.  It’s up to each model designer to decide the best approach for
>their models.
>
>Makes sense?

I think the statement “if their models can be improved” leaves too much
subjectivity in the guideline. Either we are going to avail the revised
data store model to avoid duplication of YANG schema nodes or we are going
to leverage the new data stores solely to meet the intended/applied config
requirement. If it is the latter and a good portion of the network devices
will not support, then I would agree.




>
>Kent  // as a contributor
>
>
>On 7/12/16, 11:23 AM, "netmod on behalf of Lou Berger"
><[e-mail] on behalf of [e-mail]> wrote:
>
>Acee,
>
>    I personally was assuming we'd follow 3, but I'd like to understand
>the implication of 2 as I'm not sure I really understand what you're
>thinking here.  Can you elaborate what you're thinking here?
>
>Thanks,
>
>Lou
>
>On 7/11/2016 12:36 PM, 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"
>> <[e-mail] on behalf of [e-mail]> 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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>>>>
>>>
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