Re: [netmod] schema mount and YANG library

[Robert Wilton <[e-mail]>]

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.  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.

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>.  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.

Thanks,
Rob