Re: [netmod] schema mount and YANG library

[Lou Berger <[e-mail]>]

Rob,


On January 19, 2018 1:05:46 PM Robert Wilton <[e-mail]> wrote:

>
>
> On 17/01/2018 16:40, Martin Bjorklund wrote:
>> Ladislav Lhotka <[e-mail]> wrote:
>
> <snip>
>
>>>> Ok.  I'm ok with keeping the inline case as it is.  However, I think
>>> I don't agree. The metadata annotation solves real issues.
>> One issue with the annotation is that since the schema might be
>> different in different datastores, it means that the client needs to
>> read the annotation in all datastores, and then fetch the schemas.  So
>> it is a bit more difficult to work with for a client.
> I'm still not convinced that I really understand all the arguments here:
>
> Using YLbis over YL seems to have obvious benefits to me, in that I
> perceive that it gives a cleaner data model. 

It is worth noting that the current scheme amount document can be used 
either with young library or Young Library BIS.

> But I also understand
> Lou's concerns - although its not clear to me whether Lou's primary
> concern is timing, or the fact that implementations are forced to use YLbis.
>

My concern is the delay required to reach consensus  on an unspecified 
solution that has not been discussed and may contain unknown implications. 
Keep in mind that where we are today has required compromises. Just because 
we have one party that understands what they think they're going to write 
doesn't mean that there will be changes as details are worked out, and as 
consensus is obtained.


> I also agree with Juergen that from an YLbis authors perspective YLbis
> is quite close.  I believe that the YANG model itself has been agreed
> (at the interim meeting in Nov/Dec), and hence really what is left is
> just tidying/enhancing the descriptive text in the document.
>
> I don't really understand the benefits of the metadata annotations. It
> feels like this is going to be more hassle because a client will have to
> query each datastore separately rather than getting the information in a
> single operation.
>
> A regular (without SM) NMDA NC/YANG server supports multiple datastores,
> but that information is only exposed via one so them (i.e.
> <operational>).  So, in a server supporting inline SM, it seems quite
> natural to me for the mounted schema information to also only be
> available via the mounted <operational>. 

It also enables and implementation of the current SM document to support 
nmda data stores under a inline Mount point.

> This seems to mirror the
> standard NC/YANG+YL behavior, and also seems to naturally recurse if
> required.
>
> Hence, for me, I see the choice as:
> 1) do we publish the existing model now (perhaps also mark the draft as
> experimental) followed by an updated draft with the NMDA compatible module?
> 2) do we publish both models in a single draft (e.g. with the existing
> model in an appendix)?
> 3) do we only publish a single version of the draft with an NMDA
> compliant solution.
>

There are certainly a few variants possible, but the fundamental choice is 
to go ahead with basically what passed last call or not.

Lou

> Thanks,
> Rob
>
>
>