RE: WG Review: NETCONF Data Modeling Language (netmod)

"David Harrington" <> Fri, 25 April 2008 03:06 UTC

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From: David Harrington <>
To: 'Eric Rescorla' <>, 'Bert Wijnen - IETF' <>
References: <><> <>
Subject: RE: WG Review: NETCONF Data Modeling Language (netmod)
Date: Thu, 24 Apr 2008 23:06:04 -0400
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Netconf work has been discussed on multiple different mailing lists.
To help IETF participants to find the various discussions relateds to
Netconf data modeling langauges, here is a historical listing of where
the discussions have taken place (starting in Sep 07; if anybody wants
pointers to the earlier discussions, just ask).

An overview of where discussions are held:
Netconf protocol:
Netconf Going On:
Requirements for Netconf Data Modeling Languages:
YANG design details:

Sep07: A NDM BOF was requested at ietf70 to discuss creating a WG for
Netconf data modeling
( This
thread contains a long discussion about whether a new DML is needed,
whether XSD or RNG meet the requirements, and discusses a two-tiered

The IESG and IAB held discussions and the BOF was not approved. I do
not know if these discussions are documented.

To help the Netconf community be aware of Netconf-related work at
IETF70, the following was posted to the NGO mailing list:

Some discussions were held on the NGO mailing list, whose archive can
be found at
A discussion thread on why Netconf needs a data modeling langauge can
be found at


A discussion was held in the APPS open area meeting of IETF70 instead.
The APPS area open meeting discussed why this work was needed. The
minutes unfortunately summarize this extremely lightly, and the
discussion of whether existing languages could be used was summarized
as "whether the use of schema languages was dismissed too easily",
without capturing the lengthy discussion on this point. 

The details of the discussion can be heard at
mon-am-apparea.mp3, starting at approximately 53 minutes into the
recording. A consensus call was made to determine whether there was
support for a BOF based on concrete proposals. Strong consensus for a
BOF. Concrete proposals should explain what each does well, and what
common requirements are met by the model. 

Additional discussion occurred during the OPS Open Area meeting, with
some comparion of proposals. MP3 audio is available at
mon-eve-opsarea.mp3 (starting at 2:17). details
the request for a BOF to compare approaches to NETCONF Modeling

To help make the BOF more effective, the community decided to gather
requirements from the various data modeling language constituencies,
the results of which could be used to compare the concrete proposals.
A public announcement of an ad-hoc meeting to discuss requirements was
posted to the NGO mailing list

The OPS ADs decided to create a design team to document the
requirements. The RCDML mailing list has been made available so people
can see what was discussed. See The latest rev can be found at

Between IETF70 and IETF71, the IESG and IAB reached an agreement that
no proposals could be discussed at the BOF. I do not know if those
discussions are available anywhere.


The output of the RCDML requirements-gathering effort was published
and presented at the CANMOD BOF at IETF71. Minutes are available at The
following consensus points were noted:
 - Are the requirements adequately understood?  The sense of the
    room was that the requirements are adequately understood.

  - Is there a need for this work?  The sense of the room was
    that there is a need for this work.

  - Is there sufficient agreement on the requirements
    to permit progress?  This was also the sense of the room.

  - Should an IETF working group be formed?  The sense of the
    room was that a working group to develope a Data Modeling
    Language suitable for NETCONF should be formed.

  - Would additional time spent on requirements gathering
    and analysis be well-spent?  The sense of the room was
    clearly "NO" on this question.

The OPS Open Area meeting discussed Netconf DML proposals. The minutes
are at The
MP3 audio is at

Consensus was reached that YANG and RelaxNG were liked by the most
non-author readers of the proposals, but people really liked different
aspects of the proposals.

The discussion continued in the IESG Breakout room the following day.
We do not have official minutes for that discussion. I personally
arrived about 45 minutes late to the meeting. There were
representatives from most of the constituencies that had prepared
concrete proposals. They had already agreed to a strawman approach
starting with YANG as a human-friendly DML with a mapping to one of
the XML schema langauges for machine-readability. (This was consistent
with the mood of the OPS Area open meeting the day before.) It was
decided to have the rcdml design team, plus the new Netconf chairs,
develop a proposed charter.

The discussions of the charter proposal were held on the rcdml mailing
list, whose archives can be found at This mailing list had
respresentatives from each of the constituencies that prepared
proposals for the "beauty contest". 

The design team posted the proposed charter to the NGO mailing list
for review The
design team proposal is of course no better than any other proposal,
so it was posted to NGO for further community discussion. 

Apr08: The IESG secretary announced a WG review for Netconf Data
Modeling Language to the IETF mailing list.

I hope this is helpful. Let me kniw if I can help further.

David Harrington

> -----Original Message-----
> From: [] On 
> Behalf Of Eric Rescorla
> Sent: Tuesday, April 22, 2008 5:18 PM
> To: Bert Wijnen - IETF
> Cc:;
> Subject: Re: WG Review: NETCONF Data Modeling Language (netmod)
> At Tue, 22 Apr 2008 23:10:53 +0200,
> Bert Wijnen - IETF wrote:
> > 
> > W.r.t.
> > > All this is great stuff, but it all happened after the BOF, so
> > > you can't reasonably claim that it represents BOF consensus.
> > > And since BOFs are our primary mechanism for open, cross area
> > > assessment for WG formation, I don't think it's accurate 
> to suggest
> > > that this is anywhere as near as open as actually having the
> > > discussion in the BOF and gettting consensus, nor is it a 
> substitute
> > > for that.
> > > 
> > 
> > I do not think that forming a WG MANDATES a BOF.
> > Several WGs have been formed (in the past) without a BOF.
> >
> > So pls do not depict a story as if a BOF is the only way how we
> > reach consensus in IETF on teh question of forming a WG or not.
> Yes, but when you have a BOF which doesn't come to consensus on
> a technical direction, which is then shortly followed by a proposed
> charter which *does* specify a technical direction, I think that's
> a somewhat different story.
> -Ekr
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