Re: [DNSOP] Robert Wilton's Discuss on draft-ietf-dnsop-iana-class-type-yang-03: (with DISCUSS and COMMENT)

Ladislav Lhotka <> Thu, 03 June 2021 13:17 UTC

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To: Robert Wilton <>, The IESG <>
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From: Ladislav Lhotka <>
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Date: Thu, 03 Jun 2021 15:17:14 +0200
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Subject: Re: [DNSOP] Robert Wilton's Discuss on draft-ietf-dnsop-iana-class-type-yang-03: (with DISCUSS and COMMENT)
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Hi Rob,

On 03. 06. 21 13:16, Robert Wilton via Datatracker wrote:


> ----------------------------------------------------------------------
> ----------------------------------------------------------------------
> Hi,
> One issue that I think we should should discuss and resolve (sorry for the late
> discuss ballot):
> In section 4, it states:
>    "status":  Include only if a class or type registration has been
>       deprecated or obsoleted.  In both cases, use the value "obsolete"
>       as the argument of the "status" statement.
> I know that we have had some previous discussion on this on Netmod, but, if
> draft-ietf-netmod-yang-module-versioning-02 gets standardized then it will
> effectively evolve YANG's "status deprecated" into "must implement or
> explicitly deviate" and YANG's "status obsolete" into "must not implement".  It
> wasn't clear to me that marking one of these fields as being deprecated in an
> IANA registry would mean that existing implementations must stop using it if
> they migrate to a new version of the generated YANG module.  Hence, I think
> that at this stage, it may be safer to map IANA "deprecated" into YANG's
> "status deprecated"?

Yes, this was discussed repeatedly in NETMOD and DNSOP WGs. I think we
currently have to use RFC 7950 for the status definitions, and so in YANG

   o  "deprecated" indicates an obsolete definition, but it permits
      new/continued implementation in order to foster interoperability
      with older/existing implementations.

This is incompatible with the meaning of "deprecated" in IANA
registries, which is per RFC 8126: "use is not recommended".

I agree that this discrepancy should be solved in a new version of YANG,
possibly along the lines of draft-ietf-netmod-yang-module-versioning-02,
but we can't wait for that with this draft.

> ----------------------------------------------------------------------
> ----------------------------------------------------------------------
> Hi,
> Thanks for this document.  I think that documenting this fields in YANG is a good thing.
> One minor nit:
> In an couple of places you have used 'analogically' but perhaps meant 'analogously' instead?

Yes, I will change all occurrences.

Thanks, Lada

> Thanks,
> Rob

Ladislav Lhotka
Head, CZ.NIC Labs
PGP Key ID: 0xB8F92B08A9F76C67