Subject: [yang-doctors] Fwd: Important: Guidelines for YANG module authors

From: Benoit Claise <[email-masked]>
Date: Fri, 9 Jun 2017 15:59:17 +0200

Dear YANG doctors,

Here is an important message for your YANG doctor reviews.
Rob Wilton developed some tooling to help YANG module designers to 
transition to NMDA.

Rob, would you mind explaining to everybody on this list, and maybe on 
the NETMOD if you believe this is relevant for everybody.

Regards, Benoit

-------- Forwarded Message --------
Subject: 	Important: Guidelines for YANG module authors
Date: 	Fri, 9 Jun 2017 15:56:39 +0200
From: 	Benoit Claise <[email-masked]>
To: 	NETMOD Working Group <[email-masked]>

Dear all,

Now that the new NETMOD and NETCONF charters have been approved, it's 
time to think about the guidelines for YANG module authors.

The Network Management Datastore Architecture (NMDA) addresses the 
so-called "OpState problem" that has been the subject of much discussion 
in the IETF. NMDA is still in development, and there will be a 
transition period before NMDA solutions are universally available.

The NETMOD Datastore Design Team and the Routing Yang Architecture 
Design Team have worked with Alia and Benoit to create initial 
guidelines for how the NMDA, as defined in 
draft-ietf-netmod-revised-datastores 
<https://datatracker.ietf.org/doc/draft-ietf-netmod-revised-datastores/>, 
impacts Yang models. The draft-dsdt-nmda-guidelines 
<https://datatracker.ietf.org/doc/draft-dsdt-nmda-guidelines/> 
individual draft was foundational in helping creating those guidelines.

If you have questions or concerns on how these guidelines should apply 
to work of interest, please contact your WG Chairs or ADs.

It is our strong recommendation, as ADs with agreement from the NETMOD 
WG Chairs, that models SHOULD move as quickly as possible to the NMDA. 
The specific approach to be taken for models being developed now and 
during the NMDA transition period should be based on both the expected 
usage and the maturity of the data model.

1. New models and models that are not concerned with the operational 
state of configuration information SHOULD immediately be structured to 
be NMDA-compatible.

2. Models that require immediate support for "in use" and "system 
created" information SHOULD be structured for NMDA. Then derived 
versions of these models SHOULD be created, either by hand or with 
suitable tools, that follow the current modeling strategies. In some 
cases, the non-NMDA model may be an existing model and not derived from 
the NMDA model. In all cases, the NMDA and non-NMDA modules SHOULD be 
published in the same document, with NMDA modules in the document main 
body and the non-NMDA modules in an Appendix. The use of the non-NMDA 
model will allow temporary bridging of the time period until NMDA 
implementations are available. The non-NMDA module names should include 
’-state’ appended.

We would like to thank Kent Watsen, Lou Berger, Rob Wilton, Martin 
Bjorklund, Phil Shafer, Acee Lindem, Chris Hopps, Juergen Schoenwaelder, 
and all others who helped develop these guidelines.

Regards,
Alia Atlas, Routing AD
Deborah Brungard, Routing AD
Alvaro Retana, Routing AD
Warren Kumari, Operations & Management AD
Benoit Claise, Operations & Management AD

---

From: Benoit Claise <[email-masked]>
Date: Mon, 26 Jun 2017 13:01:12 +0200

Dear YANG doctors,

Thinking some more about it, I believe we want to review one more time 
the already-reviewed YANG modules to flag whether they align with the 
guidelines below.
Background: the TEAS YANG module draft-ietf-teas-yang-te-topo, which 
we're discussing now.
On this specific one, not only it's not aligned with the NMDA 
guidelines, but he doesn't align with any of of the known YANG module 
structure, as Rob mentioned:

    My comment actually relates to the fact the structure used by TE
    YANG modules don't match any other YANG modules - they are using
    their own unique style of structure.

Practically, it means that this YANG module will be hard to integrate.

Regards, Benoit
> so-called "OpState problem" that has been the subject of much 
> discussion in the IETF. NMDA is still in development, and there will 
> be a transition period before NMDA solutions are universally available.
>
> cases, the non-NMDA model may be an existing model and not derived 
> from the NMDA model. In all cases, the NMDA and non-NMDA modules 
> SHOULD be published in the same document, with NMDA modules in the 
> document main body and the non-NMDA modules in an Appendix. The use of 
> the non-NMDA model will allow temporary bridging of the time period 
> until NMDA implementations are available. The non-NMDA module names 
> should include ’-state’ appended.
>
> Bjorklund, Phil Shafer, Acee Lindem, Chris Hopps, Juergen 
> Schoenwaelder, and all others who helped develop these guidelines.
>
> Regards,
> Alia Atlas, Routing AD
> _______________________________________________
> yang-doctors mailing list
> [email-masked]
> https://www.ietf.org/mailman/listinfo/yang-doctors