Re: [netmod] schema mount and YANG library

[Martin Bjorklund <[e-mail]>]

Lou Berger <[e-mail]> wrote:
> 
> 
> On 1/17/2018 11:18 AM, Martin Bjorklund wrote:
> ...
> >>> My main concern is actually the YL version.  I strongly think SM need
> >>> to use YL-bis rather that the old YL, so that it can support NMDA.
> >>>
> >> Right now to SM is independent of Yang Library version and can run
> >> with either.
> > No this is not correct.  SM uses a grouping from the old YANG
> > library (for the "use-schema" case),
> I thought YLbis was an updat e to UL (i.e., no name change) as such SM
> can include either.

The old "modules-state" structure is deprecated, and a new structure
that allows multiple datastores is defined.  Note that YLbis can be
used by both NMDA-capabale and non-NMDA-capabale servers.

> >   and talks about mounting
> > "modules-state" ("inline" case).
> In informative descriptions only.  Certainly these can be changed to
> allow for YL-bis if need be.
> 
> >> I certainly would expect use of Yang Library bis and nmda
> >> to have advantages.
> >>
> >>> The implementation effort for supporting the new YL in clients and
> >>> servers is minimal, esp. when compared to the efforts involved in
> >>> supporting SM.
> >>>
> >>> Adding an indirection is (for me) less important, but it has the
> >>> benefit of solving the two issues (a) and (b) above, and I haven't
> >>> seen any technical problem with it.
> >>>
> >> (A) has implementation implications and those participating in the
> >> discussion at the time expressed as not being worth the cost.
> >> I don't believe b was seen as a significant issue either.
> >>
> >>> Do you have any technical concerns with using an annotation as an
> >>> indirection?
> >>>
> >> The technicsl issue I have with the approaches the same one that was
> >> raised when debated previously, ie the implementation overhead of
> >> requiring inline schemas to be available at the top level.
> > Ok.  I'm ok with keeping the inline case as it is.  However, I think
> > we need to use the new YL-bis, so that we can support the NMDA.
> Given that NMDA support is not yet fully defined, we're still in the
> transition period where support for both NMDA and non-NMDA
> implementations need to be considered.  Rob presented some options
> earlier in the thread that I think captures this.

Again, note that YLbis supports both NMDA and non-NMDA servers.

Also note that YLbis is just a different read-only monitoring
structure.  Given an implementation that supports the old YL, it is
trivial to add support for YLbis (especially compared to the more than
non-trivial amount of work required to support schema mount...).


/martin