Extending YANG with Language Abstractions
RFC 6095

Approval announcement
Draft of message to be sent after approval:

From: The IESG <iesg-secretary@ietf.org>
To: IETF-Announce <ietf-announce@ietf.org>
Cc: Internet Architecture Board <iab@iab.org>,
    RFC Editor <rfc-editor@rfc-editor.org>
Subject: Document Action: 'Extending YANG with Language Abstractions' to Experimental RFC (draft-linowski-netmod-yang-abstract-05.txt)

The IESG has approved the following document:
- 'Extending YANG with Language Abstractions'
  (draft-linowski-netmod-yang-abstract-05.txt) as an Experimental RFC

This document has been reviewed in the IETF but is not the product of an
IETF Working Group.

The IESG contact person is Dan Romascanu.

A URL of this Internet Draft is:

Technical Summary

     YANG - the NETCONF Data Modeling Language - supports modeling of a
     tree of data elements that represent the configuration and runtime
     status of a particular network element managed via NETCONF. 
     The document defines extensions for the modeling language YANG as
      new language statements, which introduce language abstractions to
      improve the model extensibility and reuse. A model example from an
      actual network management system is given to highlight the value of 
      proposed language extensions, especially class inheritance and 

      The draft introduces object-oriented language features like class 
      inheritance and recursiveness and enables high-level modeling 
      and mapping of YANG models seamlessly to available information 
      models like TM Forum SID. As such the draft can enable easy adoption 
      of YANG language and YANG standard moduls by other SDOs (using 
      UML as modeling language) as well as using industry information 
      models as a basis for further detailed modeling and YANG module 

Working Group Summary

      The draft has been originally submitted as an individual draft to 
      the NETMOD WG addressing the gap for language abstractions 
      noted in NETMOD WG charter as an area of future work. After 
      finalizing YANG language specification the NETMOD WG decided 
      to focus on YANG module development rather than starting 
      additional work for language extensions. 
      Based on the feedback of the WG the draft specifies valuable 
      extensions to the YANG language, thus WG members proposed 
      to publish the document as an Experimental RFC. The draft
      might become a candidate for proposed standard once an 
      IETF WG starts working on an update of the YANG language
      specification as YANG 2.0.

Document Quality

      Several YANG experts from NETMOD WG and one expert 
      from IPFIX WG reviewed different versions of the draft.
      The document has been reviewed by the editor of the 
      YANG language specification Martin Bjorlund to make sure 
      the defined YANG extensions do not conflict with the YANG 

      The language extensions defined in the document have been 
      implemented with two open source tools with different code 
      base.  These tools have been used to validate the model 
      examples through the document. 


    Mehmet Ersue is the Document Shepherd for this document.
    Dan Romascanu is the Responsible Area Director.

RFC Editor Note


    memo suggests to enhance

    memo suggests enhancing

 Section 1:

After successful usage this experimental specification can be republished at IETF as a 
proposed standard possibly as part of a future version of YANG.

If this experimental specification results in successful usage, it is possible that the 
language extension defined herein could be updated to incorporate implementation 
and deployment experience, then pursued on the standards track, perhaps as 
part of a future version of YANG.

Section 1.2:

1.2. Motivation

1.2. Motivation

Following are non-exhaustive motivation examples highlighting usage scenarios for 
language abstractions.

(e.g.  TM Forum SID)

(e.g.  TM Forum SID [SID V8])

Section 2.9:

<CODE BEGINS> file "ietf-complex-types@2010-10-05.yang"

<CODE BEGINS> file "ietf-complex-types@2010-12-10.yang"

     "Editor:  Bernd Linowski
     "Editor:  Bernd Linowski

Section 4:

   Registrant Contact: See the 'Author's Addresses' section of this

   Registrant Contact: 
   Bernd Linowski (bernd.linowski.ext@nsn.com)
   Mehmet Ersue (mehmet.ersue@nsn.com)
   Siarhei Kuryla (s.kuryla@gmail.com)

Authors' Addresses:

   EMail: bernd.linowski@ext.nsn.com
   EMail: bernd.linowski.ext@nsn.com