Re: [netmod] YANG next

Robert Varga <> Wed, 24 July 2019 20:37 UTC

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To: Andy Bierman <>, Kent Watsen <>
Cc: Ladislav Lhotka <>, "" <>
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From: Robert Varga <>
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Subject: Re: [netmod] YANG next
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On 24/07/2019 20:32, Andy Bierman wrote:
> On Wed, Jul 24, 2019 at 10:28 AM Kent Watsen <
> <>> wrote:
>>>>     So you want to work on YANG 1.2, but just the parts you want to
>>>>     change? ;-)
>>>     I am actually fine with not doing any changes to YANG 1.1 at all,
>>>     except perhaps
>>>     bug fixes. This doesn't necessarily mean closing the NETMOD WG,
>>>     it would IMO be
>>>     immensely useful to rewrite the language specification and remove
>>>     NETCONF- and
>>>     XML-specific part.
>>     +1. There are plenty of ambiguities and NETCONF/XML pollution in the
>>     spec. Having the specifications in a DAG would be immensely useful :)
>     Agreed and I should've mentioned before that Martin said in Prague
>     that he'd already started this effort, seeing it as a necessary
>     pre-step before making other changes.  I'm unsure if the intention
>     is to release this by itself as an RFC 7950 bis but, if looking for
>     a minimal change, that might be it.  The next rung up would be to
>     just add clarifications.  The next rung up from there would be to
>     add only backwards-compatible changes (currently targeted by [1]). 
>     The last rung being to also target NBC changes (there's no consensus
>     to do this).
> This WG sure likes to spend time refactoring documents.

Sorry, I am not watching very closely so I have not noticed.

I regard the NETCONF coupling in RFC6020/RFC7950 as technical debt,
which when addressed will allow us to have better discussions about
modeling intent vs. XML representation.

> Moving lots of text will create bugs and strong coupling, and only help
> the standards purists.

Not necessarily. I agree with limiting the amount (and type) of text
being moved and modifications done in between.

> It will be a lot of work for the WG and IESG to review such a massive
> document split,
> and in the end we have no improvement in YANG, just more RFCs to read.

No improvement in to YANG in terms of number of features, yes.

Even if it ends up being more documents, if they are smaller and more
logically structured, they are more approachable.

Reading RFC7950 (216 pages) is far from sufficient for understanding
YANG, as you also need to understand NETCONF, which leads you down the
RFC6241 rabbit hole.

If we can get a more approachable first document, lowering the entry
barrier will be beneficial to people outside the WG(s).