On 1/16/2018 10:13 AM, Martin Bjorklund wrote:
... (trimming to topic)
rejectected by the WG multiple times. FWIW there are drafts already
with
No at all. The first and last time I proposed this was on 15 December
2017:
https://www.ietf.org/mail-archive/web/netmod/current/msg19753.html
Oh, I certainly would call you proposing that the schema for inline be
part of the rest of the schema Mount module well before that. I'm sure
I can dig up mail / slides it really necessary...
I don't think this has been proposed before. All previous proposals
were basically variants on what is now "use-schema", which works fine
when all instances have the same schema. This new proposal solves the
issue with different schemas in different instances.
I thought the previous proposals that as well, so don't see material
difference - at least from the usage standpoint. I also don't see why
the previous arguments that resulted in consensus for using Yang
Library underneath the an in line Mount Point don't apply.
B/c it doesn't work well with the NMDA. You can't mount yang library
in the configuration datastores; it has to be mounted in operational.
With meta-data, you can actually report the correct schema even in
running. (This is actually true also for pre-NMDA systems).
Understood and agree there is nothing new here and the current version
of SM (including inline) has the same limitation as rfc7895, and I'd
expect it to behave the same once we have rfc7985bis -- in fact the
inline case "just works" with YL-bis as defined today.
Martin,
you didn't respond to this point.
The argument I recall being the key point on inline was handling the
large variety of possible different implementation approaches for
modules using inline.
I think these still are covered.
For example an LNE that is implemented using
VMs which can be managed by the host at different times of the VMs
operational life cycle based on customer/provider requirements. I
really don't see how YL-bis has any bearing on this point and
Using the new proposed meta data annotation together with the new YL
means that SM can support the use case above also in an NMDA server.
I think the new proposed solution covers more use cases than the
previous solution.
how so? The inline mount point would contain YL-bis and have the same
information there, just scoped for the mount point. It's true a client
would need to understand the mount point's schema only upon parsing the
YL under the mount point and this schema could not be shared across
inline mount points. But this is as was discussed in the past and
unchanged from YL.
Do you think that there is any use case that the proposed solution
cannot handle, but the previous solution did?
yes. with VM/container technologies the YL / schema can change under
the mount point from time to time during normal operation (i.e., during
runtime, no reboot) and, in some implementations, may require some level
of rpc operation to access even the schema. The new (and previously
proposed approach) of having inline schema available from the top level
greatly complicates these cases. Also keep in mind that there will be
cases where the ability to access information under an inline mount
point will dynamically change in operation (and top level YL would need
to remove schema information for the inline mount point.) As before,
from the usage standpoint, these changes don't provide a whole lot of
value and seem to optimizing for something not needed in the inline case.
I think
it is incumbent upon those revisiting past/closed WG decisions (in
this case, inline schema being represented by YL) to argue why the
decision needs to be revisited.
I'm repeating my self: b/c the current solution doesn't work well with
the NMDA.
I simply don't understand how YL-bis works at the root node but doesn't
work equally at an inline mount point. Can you elaborate?
Lou
/martin
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