[netmod] Important: Guidelines for YANG module authors

Benoit Claise <bclaise@cisco.com> Fri, 09 June 2017 13:56 UTC

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To: NETMOD Working Group <netmod@ietf.org>
From: Benoit Claise <bclaise@cisco.com>
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Date: Fri, 9 Jun 2017 15:56:39 +0200
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Subject: [netmod] Important: Guidelines for YANG module authors
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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 
impacts Yang models. The 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.

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