Re: [Rtg-yang-coord] Fwd: [netmod] Opstate solutions discussions: update and request for WG input

["Susan Hares" <[e-mail]>]

Lou: 

My email message was to express my concerns as I2RS co-chair.  
<WG co-chair hat on> 
  [A] does not even consider ephemeral.  [B] at least considers it, but does
not match I2RS requirements.  As I2RS WG Chair, both [A] and [B] have
problems.  
<WG co-chair hat off> 

<individual contributor hat on> 
 Either [A] or [B] work as long as ephemeral state gets handed.  On B, at
least [4] and [5] at least give some ideas on handling ephemeral state. I
will work with authors [1][2][3][4][5] to suggest ephemeral improvements.
Will getting support [A] or [B] to work as individual contributor. 
<individual contributor hat off> 
Sue Hares 

========= 

 .   [A] does not even consider ephemeral.  [B] at least considers it, but
does not match it.  As I2RS WG Chair, [A] and [B] both has problems.  
<WG chair hat off> 
<individual contributor> 
[A] - will not cause me to re-write data models.  All data models (BGP,
I2RS) have split between operational data and configuration data. 
[B] As individual contributor, I appreciate that [4] and [5] at trying to
work through the details of ephemeral.  [5] has a really good diagram in
section 4 that would work for I2RS Ephemeral Configuration State.  [5] uses
the term "ephemeral configuration datastore" and correctly understands what
a get of the ephemeral datastore should result in.  It also allows multiple
layers.  However, [5] has not considered the multi-headed issues in the I2RS
ephemeral requirements.  
</individual contributor off> 
-----Original Message-----
From: Rtg-yang-coord [mailto:[e-mail]] On Behalf Of
Lou Berger
Sent: Wednesday, June 08, 2016 12:23 PM
To: Susan Hares; [e-mail]
Cc: 'Benoit Claise'; [e-mail]; 'Alia Atlas'
Subject: Re: [Rtg-yang-coord] Fwd: [netmod] Opstate solutions discussions:
update and request for WG input

Sue,

I think you're looking a step beyond the scope of decision we're considering
now. This is a fine thing, and certainly the right thing to be thinking
about from the I2RS (or any other WG working on YANG models that is
considering operational state for that matter) perspective.

The decision at hand is to choose between directions A and B.  I think you
are saying you that you like direction B but that the details aren't
sufficient for your (WG's) needs.  Is this correct?

If so, then I think you're point is that [4] and [5] need work.  We agree
with this statement and we believe consistent with the statement in B:

    -- and that the WG needs to
       formalize an opstate solution based on the approach
       discussed in [4] and [5].

So, once the WG closes on direction B (before Berlin), the WG can then start
discussing details of the WG's version of [4] and [5] -- and issues on
ephemeral support makes sense to discuss then if they still
haven't been addressed.   Of course discussion on the individual drafts
don't need to wait for the decision on basic direction.

Make sense?

Lou

On 6/8/2016 12:10 PM, Susan Hares wrote:
> Lou: 
>
> Thank you for your work on the two options.  I'd like to comment on 
> the following statement in your message statement, and reference a few 
> things in [4] and [5] regarding ephemeral state:
>
> You state: 
> "  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."
>
> In [4], the author states: 
>
>    "o  The model foresees ephemeral datastores that are by definition not
>       part of the persistent configuration of a device.  These ephemeral
>       datastores are considered to interact with the rest of the system
>       like any other control-plane mechanisms (e.g., routing protocols,
>       discovery protocols).  [XXX Note that this is different from what
>       is described in some of the I2RS documents.  XXX]"
>
> In [5], the author states: 
>
> "5.5.  Ephemeral Configuration Datastore (Optional)
>    This document does not intend to formally define an Ephemeral
>    Configuration Datastore.  In particular, it must be noted that the
>    ephemeral configuration datastore described here does not match that
>    described in version -09 of draft-ietf-i2rs-ephemeral-state
>    [I-D.ietf-i2rs-ephemeral-state].  Instead, it describes conceptually
>    how such a datastore (restricted to configuration only) might fit
>    into a conceptual refined datastore model."
>
> Therefore, the result of I2RS WG spending 2 years writing requirements 
> for the ephemeral data store that both option 2 documents "do not  
> match" the I2RS ephemeral requirements set.  [4] lumps ephemeral with 
> operational state.  [5] provides an ephemeral architecture closer to 
> I2RS ephemeral requirements, but does not understand that
draft-ietf-i2rs-ephemeral-state
> is a requirements document.    Your statement " With this approach, model
> definitions need no explicit changes to support applied configuration"
> cannot be true if you consider the I2RS data models (RIB, topology). 
>
> How is option (2) a reasonable design for ephemeral state?  I have 
> spent the last week answering questions to Juergen [4] on the I2RS
ephemeral state.
> After our discussion, he did not have any specific suggestions to 
> change these requirements 
> (https://www.ietf.org/mail-archive/web/i2rs/current/msg03688.html).
>
> Can I have an option 2b that considers ephemeral state based on the 
> requirements listed by I2RS?
>
>  Sue Hares
>  I2RS WG-chair
>
> -----Original Message-----
> From: Rtg-yang-coord [mailto:[e-mail]] On 
> Behalf Of Lou Berger
> Sent: Wednesday, June 08, 2016 9:06 AM
> To: [e-mail]
> Subject: [Rtg-yang-coord] Fwd: [netmod] Opstate solutions discussions:
> update and request for WG input
>
> FYI this decision is likely to have some impact on models under 
> development, including in the routing area. Comments on the message 
> itself should go to netmod.
>
> Lou
>
>
> --- Forwarded message ---
> From: Lou Berger <[e-mail]>
> Date: June 7, 2016 10:20:23 AM
> Subject: [netmod] Opstate solutions discussions: update and request 
> for WG input
> To: netmod WG <[e-mail]>
> CC: [e-mail]
>
> 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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