[netmod] What's the problem with NMDA? was Re: 答复: 答复: Please clarify implementation about ‘when’

Inline

Tom Petch

----- Original Message -----
From: "Andy Bierman" <andy@yumaworks.com>
To: "Rob Wilton (rwilton)" <rwilton@cisco.com>
Cc: <netmod@ietf.org>; <yangang@huawei.com>
Sent: Thursday, September 26, 2019 3:33 PM

On Thu, Sep 26, 2019 at 3:32 AM Rob Wilton (rwilton) <rwilton@cisco.com>
wrote:

>
>
> > -----Original Message-----
> > From: netmod <netmod-bounces@ietf.org> On Behalf Of Martin Bjorklund
> > Sent: 26 September 2019 08:45
> > To: lhotka@nic.cz
> > Cc: yangang@huawei.com; netmod@ietf.org
> > Subject: Re: [netmod] 答复: 答复: Please clarify implementation about
> > ‘when’
> >
> > > >
> > > > It also says in 8.2:
> > > >
> > > >    o  If a request modifies a configuration data node such that
any
> > > >       node's "when" expression becomes false, then the node in
the
> > data
> > > >       tree with the "when" expression is deleted by the server.
> > >
> > > Right. But the request won't modify a configuration data node
because
> > > it is rejected. So the premise of the above implication doesn't
hold,
> > > and the conclusion doesn't apply.
> >
> > With the same logic you can claim conformance if you reject a
request to
> > create nodes under a case if another case is active.  I think it is
quite
> > clear that this auto-deletion is part of the spec, and something
clients
> > can rely on.  If the intention had been that this was optional to
> > implement, it would have been clearly stated, and there would have
been
> > mechanism present for clients to detect this.
> >
> I don't like the 'when' behaviour, I would have rather that clients
were
> forced to delete the configuration explicitly (or pass an option for
an
> implicit delete).

I hear the opposite from customers.
They insist that the server implement every last detail of the
machine-readable YANG,
especially when-stmt auto-deletion. The auto-cleanup is seen as a
feature.

> However, I do agree with Martin & Juergen, that the intent of the spec
is
> that servers perform the 'when' auto-delete behaviour, and clients
must be
> able to rely on compliant servers behaving this way.
>

agreed.
It is hard to argue against consistent, predicable server behavior
for datastore editing.  (NP containers and NMDA are also causing
problems,
and should be fixed in yang-next if that ever happens).

<tp>

Andy

This caught my eye.  What is the problem with NMDA? Anything specific?

My own problem is that it is different to what has been proposed as
suitable for the previous 12 years but I doubt if many customers would
think that.

Tom Petch

Thanks,
> Rob
>
>

Andy

>
> >
> > /martin
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