Re: [netmod] Comment on draft-clacla-netmod-yang-model-update-02

[Ladislav Lhotka <[e-mail]>]

On Thu, 2017-11-16 at 12:59 +0800, Balazs Lengyel wrote:
> Hello Lada,
> Yes it is necessary. Just have a look at how Java uses it.  It is formulated: 
> XXX deprecated, use YYY instead.

But the data, at the end of the day, have to correspond to what is implemented
in the device. So even if an IETF WG decides to roll out a shiny new version of
module X, a vendor may still want to keep the old version, possibly forever, and
then the deprecated status information from the old version of X may be false
alarm. It would seem more appropriate for the vendor to do this kind of
signalling before a new release is coming.

On the other hand, it would IMO be too much to require that a node can be
removed only after being deprecated.

Lada

> We want to give client OSS implementers an advance warning that XXX will be
> removed, they better start planing to use YYY instead. This revision is still
> compatible, it still supports XXX, but the next one won't. This way for OSS
> the migration from XXX to YYY is less painful.
> regards Balazs
> 
> On 2017-11-16 10:04, Ladislav Lhotka wrote:
> > > BALAZS: You still need at leaast deprecated: my proposal
> > > o  "deprecated" schema nodes MUST still work as defined by the YANG
> > > module. 
> > >        The deprecated status serves only as a a warning that the schema
> > > node 
> > >        will be removed or obsoleted in the future."
> > 
> > But is this really necessary? As long as the new (incompatible) version
> > doesn't get pulled in automatically, implementors needn't care too
> > much. And if they decide to upgrade to the new version, they have to
> > check the differences anyway - as you said, they may not be in the
> > schema.
> > 
> > Lada
> > 
> 
>  
-- 
Ladislav Lhotka
Head, CZ.NIC Labs
PGP Key ID: 0xB8F92B08A9F76C67