Subject: [OPSAWG] Using YANG and its extension for Complex Types in draft-okita-ops-vnetmodel WAS:FW: RFC 6095 on Extending YANG with Language Abstractions

From: "Ersue, Mehmet (NSN - DE/Munich)" <[email-masked]>
Date: Tue, 29 Mar 2011 14:13:27 +0200

Dear Hideki,

as I commented in the OPSAWG session on Monday morning I would see it
valuable if you would use YANG as the modeling language for the
information model in your draft.

I believe the YANG extension for Complex Types, which has been published
today (a few hours ago :) as RFC 6095, will further ease your life as it
supports the top-down modeling approach with class inheritance. Base
classes you are using are already defined in this RFC and can be further
reused.

Please let me and Bernd know if you need help for modeling with YANG and
its extensions.

PS: Please check http://code.google.com/p/pyang-ct/ for an open source
validation tool for YANG Complex Types.

Cheers, 
Mehmet 

-----Original Message-----
From: [email-masked]
[mailto:[email-masked]] On Behalf Of ext
[email-masked]
Sent: Tuesday, March 29, 2011 10:51 AM
To: [email-masked]; [email-masked]
Cc: [email-masked]
Subject: RFC 6095 on Extending YANG with Language Abstractions

A new Request for Comments is now available in online RFC libraries.

        RFC 6095

        Title:      Extending YANG with Language Abstractions 
        Author:     B. Linowski, M. Ersue,
                    S. Kuryla
        Status:     Experimental
        Stream:     IETF
        Date:       March 2011
        Mailbox:    [email-masked], 
                    [email-masked], 
                    [email-masked]
        Pages:      75
        Characters: 140259
        Updates/Obsoletes/SeeAlso:   None

        I-D Tag:    draft-linowski-netmod-yang-abstract-05.txt

        URL:        http://www.rfc-editor.org/rfc/rfc6095.txt

YANG -- the Network Configuration Protocol (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.  This memo suggests enhancing
YANG with supplementary modeling features and language abstractions
with the aim to improve the model extensibility and reuse.  
This document defines an Experimental Protocol for the Internet
community.

EXPERIMENTAL: This memo defines an Experimental Protocol for the
Internet community.  It does not specify an Internet standard of any
kind. Discussion and suggestions for improvement are requested.
Distribution of this memo is unlimited.

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---

From: Paul Duffy <[email-masked]>
Date: Tue, 29 Mar 2011 19:16:31 -0400

Hi Mehmet,

Can you help me understand what compelling advantages YANG offers versus 
working with native XML schema / modeling tools?  Is YANG simply an 
SMI-like veneer atop XSD?

I'm struggling to understand why I would go down a YANG path.

Thanks

On 3/29/2011 8:13 AM, Ersue, Mehmet (NSN - DE/Munich) wrote:
> OPSAWG mailing list
> [email-masked]
> https://www.ietf.org/mailman/listinfo/opsawg
>

---

From: Andy Bierman <[email-masked]>
Date: Tue, 29 Mar 2011 22:34:03 -0700

Hi,

You seem to understand that SMIv2 is the data modeling language
used to define content for the SNMP protocol.  It contains constructs
that allow the SNMP protocol operations to be implemented in an
interoperable manner.

YANG serves the same purpose for the NETCONF protocol.
If you are not using NETCONF, then ignore YANG.
YANG does not model XML instance documents like XSD.
It models operations, notifications, and datastore content
within a NETCONF server.

Andy

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf Of Paul Duffy
Sent: Tuesday, March 29, 2011 4:17 PM
To: Ersue, Mehmet (NSN - DE/Munich)
Cc: [email-masked]; [email-masked]; Linowski, Bernd (EXT-Other - DE)
Subject: Re: [OPSAWG] Using YANG and its extension for Complex Types in draft-okita-ops-vnetmodel WAS:FW: RFC 6095 on Extending YANG with Language Abstractions

Hi Mehmet,

Thanks

---

From: "Ersue, Mehmet (NSN - DE/Munich)" <[email-masked]>
Date: Wed, 30 Mar 2011 12:45:21 +0200

Dear Paul,

if you want to do configuration management you should consider to use
NETCONF as it has been specialized for configuration management and
provides substantial improvements compared to SNMP for configuration.

Actually YANG and NETCONF are a well-designed pair and YANG is the
"NETCONF modeling language".

There are many reasons why we developed YANG. Some of them are:

- YANG uses many years of experience with proprietary NETCONF data
modeling languages at IETF and lessons learned from SMIv2 and the SMIng
project 
- YANG has a trivial syntax, is text-based, "human-readable" and easy to
learn but is still sufficiently flexible and extensible
- YANG sees the data model as a contract between the device and the
application
   - follows SMIv2 model and allows modules to be published
independently
   - provides protocol-specific data model definition
   - maps directly to XML content (on the wire)
- YANG is specialized for defining configuration models:
   - prepared as a modeling for conceptual datastore(s) as in
SNMP/NETCONF
   - distinguishes between read-only and read-write data
   - provides full support for keys (!!)
   - provides advanced features for configuration module modeling: 
      - formal description of the conceptual data within NETCONF
configuration datastores
      - transactions (!!!) with partial-locking of a datastore
      - custom RPCs and notifications

Last but not least the Experimental RFC 6095 goes one step further and
provides YANG language extensions for Complex Types and Typed Instance
Identifiers and aims to
ease the life of implementers if they follow a top-down modeling
approach and want to use abstract classes and inheritance. 

There are many open-source tools available for NETCONF and YANG. Please
consider to check for implementations and tools:
http://trac.tools.ietf.org/wg/netconf/trac/wiki 
http://www.netconfcentral.org/
http://www.yangcentral.org/
http://code.google.com/p/pyang-ct/ (RFC6095)

Cheers, 
Mehmet 

> From: ext Andy Bierman [mailto:[email-masked]]
> Sent: Wednesday, March 30, 2011 7:34 AM
> To: [email-masked]; Ersue, Mehmet (NSN - DE/Munich)
> Cc: [email-masked]; [email-masked]; Linowski,
Bernd
> (EXT-Other - DE)
> Subject: RE: [OPSAWG] Using YANG and its extension for Complex Types
> indraft-okita-ops-vnetmodel WAS:FW: RFC 6095 on Extending YANG with
> Language Abstractions
> 
> Hi,
> 
> Cc: [email-masked]; [email-masked]; Linowski,
Bernd
> (EXT-Other - DE)
> Subject: Re: [OPSAWG] Using YANG and its extension for Complex Types
in
> draft-okita-ops-vnetmodel WAS:FW: RFC 6095 on Extending YANG with
> Language Abstractions
> 
> Hi Mehmet,
> 
> > today (a few hours ago :) as RFC 6095, will further ease your life
as
> it