NETCONF Data Modeling Language (netmod)
---------------------------------------

 Charter
 Last Modified: 2009-05-06

 Current Status: Active Working Group

 Chair(s):
     David Partain  <david.partain@ericsson.com>
     David Kessens  <david.kessens@nsn.com>

 Operations and Management Area Director(s):
     Dan Romascanu  <dromasca@avaya.com>
     Ronald Bonica  <rbonica@juniper.net>

 Operations and Management Area Advisor:
     Dan Romascanu  <dromasca@avaya.com>

 Mailing Lists: 
     General Discussion:netmod@ietf.org
     To Subscribe:      netmod-request@ietf.org
         In Body:       In msg body: subscribe
     Archive:           http://www.ietf.org/mail-archive/web/netmod/

Description of Working Group:

The NETCONF Working Group has completed a base protocol to be
used for configuration management.  However, the NETCONF protocol
does not include a standard content layer.  The specifications do
not include a modeling language or accompanying rules that can be
used to model the management information that is to be configured
using NETCONF. This has resulted in inconsistent syntax and
interoperability problems. The purpose of NETMOD is to support
the ongoing development of IETF and vendor-defined data models
for NETCONF.

NETMOD's requirements are drawn from the RCDML requirements draft
(draft-presuhn-rcdml) and documents referenced therein.

The WG will define a "human-friendly" modeling language defining
the semantics of operational data, configuration data,
notifications, and operations.  This language will focus on
readability and ease of use.  This language must be able to serve
as the normative description of NETCONF data models.  The WG will
use YANG (draft-bjorklund-yang) as its starting point for this
language.

Language abstractions that facilitate model extensibility and
reuse have been identified as a work area and will be considered
as a work item or may be integrated into the YANG document based
on WG consensus.

The WG will define a canonical mapping of this language to
NETCONF XML instance documents, the on-the-wire format of
YANG-defined XML content.  Only data models defined in YANG will
have to adhere to this on-the-wire format.

In order to leverage existing XML tools for validating NETCONF
data in various contexts and also facilitate exchange of data
models and schemas with other IETF working groups, the WG will
define standard mapping rules from YANG to the DSDL data modeling
framework (ISO/IEC 19757) with additional annotations to preserve
semantics.

The initial YANG mapping rules specifications are expressly defined for
NETCONF modeling.  However, there may be future areas of
applicability beyond NETCONF, and the WG must provide suitable
language extensibility mechanisms to allow for such future work.
The NETMOD WG will only address modeling NETCONF devices and the
language extensibility mechanisms.  Any application of YANG to
other protocols is future work.

The WG will consult with the NETCONF WG to ensure that NETMOD's
decision do not conflict with planned work in NETCONF (e.g.,
locking, notifications).

While it is desirable to provide a migration path from existing
MIB modules to YANG data models (modules), it is not a
requirement to provide full compatibility between SMIv2 and YANG.
The Working Group will determine which constructs (e.g., conformance
statements) are not relevant for translation from SMIv2 to YANG. YANG 
is
also permitted to introduce constructs that cannot be expressed in
SMIv2.  However, all basic types that can be represented in SMIv2 must
be expressible in YANG.

Initial deliverables are below.  The working group may choose to
combine multiple deliverables into a single document where deemed
appropriate.

1. An architecture document explaining the relationship
between YANG and its inputs and outputs. (informational)

2. The YANG data modeling language and semantics (proposed
standard)

3. Mapping rules of YANG to XML instance data in NETCONF
(proposed standard)

4. YIN, a semantically equivalent fully reversible mapping to an
XML-based syntax for YANG.  YIN is simply the data model in an XML
syntax that can be manipulated using existing XML tools (e.g., XSLT)
(proposed standard)

5. Mapping rules of YANG to DSDL data modeling framework (ISO/IEC
19757), including annotations for DSDL to preserve top-level
semantics during translation (proposed standard).

6. A standard type library for use by YANG (proposed standard)

 Goals and Milestones:

   Jun 2008       All _individual_ drafts available that will be used as input 
                into the WG documents (draft-bjorklund-yang, architecture 
                draft, YIN draft, YANG standard library draft, DSDL mapping 
                rules draft) 

   Aug 2008       Initial set of WG drafts: architecture, YANG, YIN, YANG 
                standard library, DSDL mapping rules (if there is one/more 
                individual draft), based on WG decisions in Dublin 

   Sep 2008       Initial DSDL mapping rules document 

   Oct 2008       01 of YANG, DSDL, architecture, YIN, and standard library 
                draft. If split out, -00 of on-the-wire XML draft. 

   May 2009       WGLC for Netmod architecture document 

   May 2009       Initial YANG Usage guidelines document available as a working 
                group document 

   Jun 2009       Submit the architecture document to the IESG for publication as 
                an Informational RFC 

   Aug 2009       WGLC for YANG, YIN, XML on-the-wire (if split out), YANG 
                standard library, DSDL mapping rules 

   Sep 2009       Submit YANG, YIN, XML on-the-wire (if split out), YANG standard 
                library, DSDL mapping rules to the IESG for publication as a 
                Proposed Standard 

   Sep 2009       Submit YANG Usage Guidelines to the IESG for publication as an 
                Informational RFC 


 Internet-Drafts:

Posted Revised         I-D Title   <Filename>
------ ------- --------------------------------------------
May 2008 Jan 2010   <draft-ietf-netmod-yang-10.txt>
                YANG - A data modeling language for NETCONF 

Sep 2008 Dec 2009   <draft-ietf-netmod-yang-types-05.txt>
                Common YANG Data Types 

Feb 2009 Oct 2009   <draft-ietf-netmod-dsdl-map-04.txt>
                Mapping YANG to Document Schema Definition Languages and 
                Validating NETCONF Content 

May 2009 Jan 2010   <draft-ietf-netmod-yang-usage-03.txt>
                Guidelines for Authors and Reviewers of YANG Data Model 
                Documents 

 Request For Comments:

  None to date.