Hi Amanda,

Thanks for the clearly detailed look you took at the drafts.

I'll start with some initial thoughts below but before I get too far, it may be 
good to see another person or two from NETMOD chime in to make sure I'm on the 
right track 😊

Please see inline.

Jason

> -----Original Message-----
> From: Amanda Baber via RT <[email protected]>
> Sent: Friday, October 3, 2025 8:53 PM
> To: [email protected]
> Cc: [email protected]; draft-ietf-netmod-
> [email protected]; [email protected]; draft-ietf-netmod-yang-module-
> [email protected]
> Subject: [netmod] [IANA #1429269] Heads-up! Changes coming in YANG
> 
> 
> CAUTION: This is an external email. Please be very careful when clicking 
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> 
> 
> Hi Mahesh,
> 
> Unfortunately, I can't give anyone access to our drive, but I'm attaching a
> Word version that you're welcome to make available via someone else's. I
> think our level of inexpertise will be pretty clear.
> 
> To wrap up our semver notes, this is a list of registry/YANG updates that we
> wouldn't be sure how to classify:
> 
> Replacing reference (as in an obsoleted RFC) - BC? Editorial?
[>>JTS:] This is allowed in RFC7950 ("A "reference" statement may be added or 
updated.") and Module Versioning mostly keeps the same rules as 7950 to 
determine NBC vs BC (only a few exceptions). I'd propose this is simply 
"editorial".

> 
> Listing additional (not replacement) reference for registration - BC? 
> Editorial?
[>>JTS:] BC and editorial.
(I'm assuming the net result in the YANG module vs the previously published 
version is an additional or changed 'reference' statement right?)

> 
> For assignments made immediately after the IESG approved an I-D for
> publication: replacing draft string w/newly-assumed RFC number upon
> publication (also, this is assuming that we're only replacing the enum's
> reference, not the original revision statement's reference) - Editorial?
[>>JTS:] I'm not 100% certain what change to the YANG you're talking about here 
(vs the previous version of the YANG). Can you give a concrete example of a 
line(s) in the YANG before and after this change?


> 
> Errata reports for YANG modules or underlying registries -- does
> NBC/BC/editorial status depend on the content of the errata reports?
[>>JTS:] No - I don't think so. The NBC vs BC categorization is purely based on 
the content of the module (before vs after).


> 
> Removing registration (similar to obsoleting, but no trace left behind) - NBC?
[>>JTS:] What change in the YANG does this result in? If it removes a line of 
YANG then strictly speaking this isn't allowed in RFC7950 and hence we'd 
consider it NBC.

> 
> Chairs decide to mark value as "deprecated" while removing the
> name/description of the registration - Still BC? Also, what's the status sub-
> statement in this scenario? (we might need to address approaches to
> deprecation in 8126bis, not sure)
[>>JTS:] Sorry - not positive what YANG change this results in?  Same for the 
next two. Can you give examples?

> 
> Early allocation allowed to expire  + chairs decide to leave the registration 
> as-is
> without removing or marking it "deprecated" - NBC? Not sure how we add a
> status sub-statement for this either. (These are rare, and once we were asked
> to revive the expired allocation a couple of years later.)
> 
> Changes to the registration that won't be reflected in the module (for 
> example,
> if there are changes, substantive or otherwise, to other fields beyond "name"
> and "description," or if we need to update a non-IETF reference) - no change?
> 
> thanks,
> Amanda
> 
> On Tue Sep 30 17:54:43 2025, [email protected] wrote:
> > Hi Amanda,
> >
> > Thanks for sharing your thoughts on the upcoming changes w.r.t. YANG
> > semver. I am going to loop in the rest of the WG, but mainly the
> > authors of the three drafts, to help me here.
> >
> > Could you start by sharing a link to the Google document that has the
> > current set of instructions you follow to update an IANA YANG module?
> > I am going to suggest that the authors of the three drafts, but really
> > anyone from the WG, suggest edits to the document that identify the
> > steps that should be taken by IANA once a YANG document is approved.
> > Once folks have had a chance to review the document, we can meet in
> > 124 (or sooner) to finalize the instructions.
> >
> > Does that work?
> >
> > > On Sep 18, 2025, at 6:58 PM, Amanda Baber via RT <iana-
> > > [email protected]> wrote:
> > >
> > > Hi Mahesh,
> > >
> > > Thanks for the early warning. I looked at a couple of these several
> > > meetings ago, but thought we were just sort of condemned to have to
> > > muddle through.
> > >
> > > So we're going to put a table together that lists various
> > > registry/YANG module update scenarios (including reference updates,
> > > different kinds of errata, different types of registry updates, etc.)
> > > and whether we think the change counts as NBC, BC, or editorial. I'll
> > > send you that and some related questions next week.
> > >
> > > In general, this is pretty rough going for us. draft-ietf-netmod-
> > > yang-semver is the toughest. The IANA Considerations section directs
> > > us to Section 4 and particularly Section 4.5, but because we're not
> > > branching or (I think) using _compatible modifiers, we have to read
> > > around much of the text to find the instructions that we do need to
> > > use.
> > >
> > > I need to note again that our roles are really administrative, not
> > > technical, and our limited experience with scripting or programming
> > > classes (which future employees likely won't have coming in) isn't
> > > doing us much good here.
> > >
> > > In order to implement all this on an irregular basis, and to train
> > > future co-workers, we're going to have to distill this into clear
> > > instructions for ourselves, which we'll add to a lengthy internal
> > > "Special Instructions for YANG and MIB Files" document that currently
> > > includes topics like "don't rename files" and "how to run pyang."
> > >
> > > This isn't optimal. We'll have to run our instructions by an expert
> > > to make sure that we've captured everything correctly, and perhaps
> > > ask for another review later if a question comes up, and because
> > > we'll be storing this on Google drive or some wiki, there's always
> > > the danger that we'll accidentally delete something crucial.
> > >
> > > I didn't feel we could ask for this before, but it doesn't hurt to
> > > mention it, I suppose: our strong preference would be for the WG to
> > > produce a short document for IANA that doesn't reproduce all of the
> > > reasoning behind the changes, but simply tells us which rules apply
> > > to IANA-maintained YANG modules and what IANA needs to start
> > > doing/revising once the document's been approved.
> > >
> > > Our general takeaways:
> > >
> > > 1)  we're going to be adding a "rev:non-backwards-compatible" sub-
> > > statement to revisions where necessary, which might require more
> > > editorial judgment than we're able to apply where description changes
> > > are concerned;
> > >
> > > 2) when a registry update requires it (or likely earlier, so we don't
> > > have pressure to publish), we're going to update the most recent
> > > versions of each existing IANA-maintained module to add an x.y.z
> > > [NBC.BC.editorial] version substatement to every (I think) existing
> > > revision statement (note: someone should review the updated modules
> > > before we post them); and
> > >
> > > 3) draft-ietf-netmod-yang-module-filename doesn't seem to tell/ask us
> > > to do anything. Should we use the new naming pattern when we add the
> > > new revision substatements, and stop using dates?
> > >
> > > This text at the end of Section 4.5 just registered: 'However, the
> > > reverse does not necessarily hold, i.e., if the MAJOR version has
> > > been incremented it does not necessarily mean that a "rev:non-
> > > backwards-compatible' statement would be present." Does this apply to
> > > IANA-maintained modules? How would we know that this needed to be
> > > done? Three of us have read these now, but I'm concerned that we may
> > > have missed other items like this that may/may not apply to us.
> > >
> > > If there's any general YANG training you could point us to that isn't
> > > in RFC format, I think that would be helpful!
> > >
> > > thanks,
> > > Amanda
> > >
> > > On Wed Sep 10 21:02:17 2025, [email protected] wrote:
> > >> Hi,
> > >>
> > >> I hope this is the right email address to send this information to.
> > >>
> > >> I am currently reviewing three documents that advocate how YANG
> > >> modules should be versioned and the new files that should be created
> > >> to support that new versioning method. They will be in front of the
> > >> IESG in the next few weeks. These three documents are:
> > >>
> > >> draft-ietf-netmod-yang-semver
> > >> draft-ietf-netmod-yang-module-filename
> > >> draft-ietf-netmod-yang-module-versioning
> > >>
> > >> We have had meetings with the IETF tools team and the RPC center to
> > >> explain the changes. Since these changes impact IANA, I would
> > >> suggest
> > >> that you take some time to read through the documents and let me
> > >> know
> > >> if you have questions. I can call out the experts to explain the
> > >> changes.
> > >>
> > >> Thanks.
> > >>
> > >> Mahesh Jethanandani
> > >> [email protected]
> > >
> >
> >
> > Mahesh Jethanandani
> > [email protected]

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