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Versions: 00 01

Network Working Group                                          J. Clarke
Internet-Draft                                                 B. Claise
Intended status: Standards Track                     Cisco Systems, Inc.
Expires: February 16, 2018                               August 15, 2017


                    YANG module for yangcatalog.org
                  draft-clacla-netmod-model-catalog-01

Abstract

   This document specifies a YANG module that contains metadata related
   to YANG modules and vendor implementations of those YANG modules.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on February 16, 2018.

Copyright Notice

   Copyright (c) 2017 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.






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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Status of Work and Open Issues  . . . . . . . . . . . . .   3
   2.  Learning from Experience  . . . . . . . . . . . . . . . . . .   3
     2.1.  YANG Module Library . . . . . . . . . . . . . . . . . . .   4
     2.2.  YANG Catalog Data Model . . . . . . . . . . . . . . . . .   4
     2.3.  Module Sub-Tree . . . . . . . . . . . . . . . . . . . . .   6
     2.4.  Compilation Information . . . . . . . . . . . . . . . . .   8
     2.5.  Maturity Level  . . . . . . . . . . . . . . . . . . . . .  10
     2.6.  Implementation  . . . . . . . . . . . . . . . . . . . . .  10
     2.7.  Vendor Sub-Tree . . . . . . . . . . . . . . . . . . . . .  11
     2.8.  Regex Expression Differences  . . . . . . . . . . . . . .  12
   3.  YANG Catalog Use Cases  . . . . . . . . . . . . . . . . . . .  13
     3.1.  YANG Search Metadata  . . . . . . . . . . . . . . . . . .  13
     3.2.  Identify YANG Module Support in Devices . . . . . . . . .  13
   4.  YANG Catalog YANG module  . . . . . . . . . . . . . . . . . .  13
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .  29
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  29
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  29
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .  29
     7.2.  Informative References  . . . . . . . . . . . . . . . . .  30
     7.3.  URIs  . . . . . . . . . . . . . . . . . . . . . . . . . .  30
   Appendix A.  Acknowledgments  . . . . . . . . . . . . . . . . . .  30
   Appendix B.  Changes From Previous Revisions  . . . . . . . . . .  31
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  31

1.  Introduction

   YANG [RFC6020] [RFC7950] became the standard data modeling language
   of choice.  Not only is it used by the IETF for specifying models,
   but also in many Standard Development Organizations (SDOs),
   consortia, and open-source projects: the IEEE, the Broadband Forum
   (BFF), DMTF, MEF, ITU, OpenDaylight, Open ROADM, Openconfig, sysrepo,
   and more.

   With the rise of data model-driven management and the success of YANG
   as a key piece comes a challenge: the entire industry develops YANG
   models.  In order for operators to automate coherent services, the
   industry must ensure the following:

   1.  Data models must work together

   2.  There exists a toolchain to help one search and understand models

   3.  Metadata is present to further describe model attributes





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   The site <yangcatalog.org> (and the YANG catalog that it provides) is
   an attempt to address these key tenants.  From a high level point of
   view, the goal of this catalog is to become a reference for all YANG
   modules available in the industry, for both YANG developers (to
   search on what exists already) and for operators (to discover the
   more mature YANG models to automate services).  This YANG catalog
   should not only contain pointers to the YANG modules themselves, but
   also contain metadata related to those YANG modules: What is the
   module type (service model or not?); what is the maturity level?
   (e.g., for the IETF: is this an RFC, a working group document or an
   individual draft?); is this module implemented?; who is the contact?;
   is there open-source code available?  And we expect many more in the
   future.  The industry has begun to understand that the metadata
   related to YANG models become equally important as the YANG models
   themselves.

   This document defines a YANG [RFC6020] module called yang-
   catalog.yang that contains the metadata definitions that are
   complementary to the related YANG modules themselves.  The design for
   this module is based on experience and real code.  As such, it's
   expected that this YANG module will be a living document.
   Furthermore, new use cases, which require new metadata in this YANG
   module, are discovered on a regular basis.

   The yangcatalog.org instantiation of the catalog provides a means for
   module authors and vendors implementing modules to upload their
   metadata, which is then searchable via an API, as well as using a
   variety of web-based tools.  The instructions for contributing and
   searching for metadata can be found at <yangcatalog.org/
   contributing.php>.

1.1.  Status of Work and Open Issues

   The top open issues are:

   1.  Obtain feedback from vendors and SDOs

   2.  Socialize module at the IETF and incorporate feedback

   3.  Provide module bundle support

2.  Learning from Experience

   While implementing the catalog and tools at yangcatalog.org, we
   initially looked at the "Catalog and registry for YANG models"
   [I-D.openconfig-netmod-model-catalog] as a starting point but we
   quickly realized that the objectives are different.  As a
   consequence, even if some of the information is similar, this YANG



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   module started to diverge.  Below are our observations and the
   justifications for the divergence.

2.1.  YANG Module Library

   In order for the YANG catalog to become a complete inventory of which
   models are supported on the different platforms, content such as the
   support of the YANG module/deviation/feature/etc. should be easy to
   import and update.  An easy way to populate this information is to
   have a similar structure as the YANG Module Library [RFC7895].  That
   way, querying the YANG Module Library from a platform provides,
   directly in the right format, the input for the YANG catalog
   inventory.

   There are some similar entries between the YANG Module Library and
   the Openconfig catalog.  For example, the Openconfig catalog model
   defines a "uri" leaf which is similar to "schema" from [RFC7895]).
   And this adds to the overall confusion.

2.2.  YANG Catalog Data Model

   The structure of the yang-catalog.yang module described in this
   document is found below:

module: yang-catalog
+--rw catalog
   +--rw modules
   |  +--rw module* [name revision organization]
   |     +--rw name                     yang:yang-identifier
   |     +--rw revision                 union
   |     +--rw schema?                  inet:uri
   |     +--rw generated-from?          enumeration
   |     +--rw maturity-level?          enumeration
   |     +--rw document-name?           string
   |     +--rw author-email?            yc:email-address
   |     +--rw reference?               inet:uri
   |     +--rw module-classification    enumeration
   |     +--rw compilation-status?      enumeration
   |     +--rw compilation-result?      string
   |     +--rw prefix?                  string
   |     +--rw yang-version?            enumeration
   |     +--rw description?             string
   |     +--rw contact?                 string
   |     +--rw module-type?             enumeration
   |     +--rw tree-type?               enumeration
   |     +--rw organization             string
   |     +--rw ietf
   |     |  +--rw ietf-wg?   string



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   |     +--rw namespace                inet:uri
   |     +--rw submodule* [name revision]
   |     |  +--rw name        yang:yang-identifier
   |     |  +--rw revision    union
   |     |  +--rw schema?     inet:uri
   |     +--rw implementations
   |        +--rw implementation* [vendor platform software-version software-flavor]
   |           +--rw vendor              string
   |           +--rw platform            string
   |           +--rw software-version    string
   |           +--rw software-flavor     string
   |           +--rw os-version?         string
   |           +--rw feature-set?        string
   |           +--rw os-type?            string
   |           +--rw feature*            yang:yang-identifier
   |           +--rw deviation* [name revision]
   |           |  +--rw name        yang:yang-identifier
   |           |  +--rw revision    union
   |           +--rw conformance-type?   enumeration
   +--rw vendors
+--rw vendor* [name]
 +--rw name         string
 +--rw platforms
+--rw platform* [name]
   +--rw name                 string
   +--rw software-versions
+--rw software-version* [name]
 +--rw name                string
 +--rw software-flavors
  +--rw software-flavor* [name]
     +--rw name         string
     +--rw protocols
     |  +--rw protocol* [name]
     |     +--rw name                identityref
     |     +--rw protocol-version?   string
     |     +--rw capabilities*       string
     +--rw modules
        +--rw module* [name revision organization]
           +--rw name                -> /catalog/modules/module/name
           +--rw revision            -> /catalog/modules/module/revision
           +--rw organization        -> /catalog/modules/module/organization
           +--rw os-version?         string
           +--rw feature-set?        string
           +--rw os-type?            string
           +--rw feature*            yang:yang-identifier
           +--rw deviation* [name revision]
           |  +--rw name        yang:yang-identifier
           |  +--rw revision    union



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           +--rw conformance-type?   enumeration

   Various elements of this module tree will be discussed in the
   subsequent sections.

2.3.  Module Sub-Tree

   Each module in the YANG Catalog is enumerated by its metadata and by
   various vendor implementations.  While initially each module used the
   "module-list" grouping from the YANG Library [RFC7895], it was found
   that some of the nodes within that grouping such as "conformance-
   type", "feature", and "deviation" are only valid when a module is
   implemented by a server.  As pure YANG data (which the Catalog is) it
   is not possible to provide meaningful values for those nodes.  As
   such, common leafs were extracted from the YANG Library's "module-
   list" for use in the module sub-tree of yang-catalog.  Those server-
   specific nodes are moved under the implementation sub-tree.  The
   yang-catalog module then augments these common nodes to add metadata
   elements that aid module developers and module consumers alike in
   understanding the relative maturity, compilation status, and the
   support contact(s) of each YANG module.






























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+--rw modules
|  +--rw module* [name revision organization]
|     +--rw name                     yang:yang-identifier
|     +--rw revision                 union
|     +--rw schema?                  inet:uri
|     +--rw generated-from?          enumeration
|     +--rw maturity-level?          enumeration
|     +--rw document-name?           string
|     +--rw author-email?            yc:email-address
|     +--rw reference?               inet:uri
|     +--rw module-classification    enumeration
|     +--rw compilation-status?      enumeration
|     +--rw compilation-result?      string
|     +--rw prefix?                  string
|     +--rw yang-version?            enumeration
|     +--rw description?             string
|     +--rw contact?                 string
|     +--rw module-type?             enumeration
|     +--rw tree-type?               enumeration
|     +--rw organization             string
|     +--rw ietf
|     |  +--rw ietf-wg?   string
|     +--rw namespace                inet:uri
|     +--rw submodule* [name revision]
|     |  +--rw name        yang:yang-identifier
|     |  +--rw revision    union
|     |  +--rw schema?     inet:uri
|     +--rw implementations
|        +--rw implementation* [vendor platform software-version software-flavor]
|           +--rw vendor              string
|           +--rw platform            string
|           +--rw software-version    string
|           +--rw software-flavor     string
|           +--rw os-version?         string
|           +--rw feature-set?        string
|           +--rw os-type?            string
|           +--rw feature*            yang:yang-identifier
|           +--rw deviation* [name revision]
|           |  +--rw name        yang:yang-identifier
|           |  +--rw revision    union
|           +--rw conformance-type?   enumeration

   Many of these additional metadata fields are self-explanatory,
   especially given their descriptions in the module itself and the fact
   that many elements translate directly to YANG schema elements.
   However, those requiring additional explanation or context as to why
   they are needed are described in the subsequent sections.




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2.4.  Compilation Information

   For the inventory to be complete, YANG modules at different stages of
   their lifecyle should be taken into account, including YANG modules
   that are clearly works-in-progress (i.e., that do not validate
   correctly, either because of faulty YANG constructs, because of a
   faulty imported YANG module, or simply because of warnings).  The
   results of compilation testing are denoted in the "compilation-
   status" leaf with the output of the tests stored in the "compilation-
   result" leaf.  Note that some warnings seen in "compilation-result"
   are not always show-stoppers from a code generation point of view.
   Nonetheless, the compilation or validation status, along with the
   compilation output, provide a clear indication of a given YANG
   module's development phase and stability.





































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leaf compilation-status {
type enumeration {
enum passed {
  description
    "All compilers were able to compile this YANG module without
     any errors or warnings.";
}
enum passed-with-warnings {
  description
    "All compilers were able to compile this YANG module without
     any errors, but at least one of them caught a warning.";
}
enum failed {
  description
    "At least one of compilers found an error while
     compiling this YANG module.";
}
enum pending {
  description
    "The module was just added to the catalog and compilation testing is still
     in progress.";
}
enum unknown {
  description
    "There is not sufficient information about compilation status.  This Could
     mean compilation crashed causing it not to complete fully.";
}
}
description
"Status of the module, whether it was possible to compile this YANG module or
 there are still some errors/warnings.";
}
leaf compilation-result {
type string;
description
"Result of the compilation explaining specifically what error or warning occurred.
 This is not existing if compilation status is PASSED.";
}

   The current instantiation of the YANG Catalog at
   <https://yangcatalog.org> uses a number of different YANG compilers
   for testing.  The wrapper that handles validation attempts to use
   metadata from the catalog to determine which tests to perform on a
   given module.  For example, if the module is authored by the IETF,
   IETF-specific tests will be conducted to provide the most accurate
   and complete set of tests possible.





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2.5.  Maturity Level

   Models also have inherent maturity levels from their respective
   Standards Development Organizations (SDOs).  These maturity levels
   help module consumers understand how complete, tested, etc. a module
   is.

leaf maturity-level {
type enumeration {
enum ratified {
  description
    "Maturity of a module that is fully approved (e.g., a standard).";
}
enum adopted {
  description
    "Maturity of a module that is actively being developed by a organization towards ratification.";
}
enum initial {
  description
    "Maturity of a module that has been initially created, but has no official
     organization-level status.";
}
enum not-applicable {
  description
    "The maturity level is not used for vendor-supplied models, and thus all vendor
     modules will have a maturity of not-applicable";
}
}
description
"The current maturity of the module with respect to the body that created it.
 This allows one to understand where the module is in its overall life cycle.";
}

   This enumeration mapping has been implemented for the YANG modules
   from IETF and BBF.  The "maturity-level" MUST be "not-applicable" for
   all vendor-authored modules.

2.6.  Implementation

   As of version 02 of openconfig-model-catalog.yang
   [I-D.openconfig-netmod-model-catalog] it is not possible to identify
   the implementations of one specific module.  Instead modules are
   grouped into feature-bundle, and feature-bundles are implemented by
   devices.  Because of this, we added our own implementation sub-tree
   under each module to yang-catalog.yang.  Our implementation sub-tree
   is:





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+--rw implementation* [vendor platform software-version software-flavor]
 +--rw vendor              string
 +--rw platform            string
 +--rw software-version    string
 +--rw software-flavor     string
 +--rw os-version?         string
 +--rw feature-set?        string
 +--rw os-type?            string
 +--rw feature*            yang:yang-identifier
 +--rw deviation* [name revision]
 |  +--rw name        yang:yang-identifier
 |  +--rw revision    union
 +--rw conformance-type?   enumeration

   The keys in this sub-tree can be used in the "vendor" sub-tree
   defined below to walk through each vendor, platform, and software
   release to get a full list of supported YANG modules for that
   release.

   The "software-flavor" key leaf identifies a variation of a specific
   version where YANG model support may be different.  Depending on the
   vendor, this could be a license, additional software component, or a
   feature set.

   The other non-key leaves in the implementation sub-tree represent
   optional elements of a software release that some vendors may choose
   to use for informational purposes.  These leafs are duplicated under
   the vendor sub-tree.

2.7.  Vendor Sub-Tree

   The vendor sub-tree provides a way, especially for module consumers,
   to walk through a specific device and software release to find a list
   of modules supported therein.  This sub-tree turns the
   "implementation" sub-tree on its head to provide an optimized index
   for one wanting to go from a platform to a full list of modules.

   In addition to the module list, the vendor sub-tree lists the YANG-
   based protocols (e.g., NETCONF or RESTCONF) that the platforms
   support.











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+--rw vendor* [name]
 +--rw name         string
 +--rw platforms
    +--rw platform* [name]
       +--rw name                 string
       +--rw software-versions
          +--rw software-version* [name]
             +--rw name                string
             +--rw software-flavors
                +--rw software-flavor* [name]
                   +--rw name         string
                   +--rw protocols
                   |  +--rw protocol* [name]
                   |     +--rw name                identityref
                   |     +--rw protocol-version?   string
                   |     +--rw capabilities*       string
                   +--rw modules
                      +--rw module* [name revision organization]
                         +--rw name                -> /catalog/modules/module/name
                         +--rw revision            -> /catalog/modules/module/revision
                         +--rw organization        -> /catalog/modules/module/organization
                         +--rw os-version?         string
                         +--rw feature-set?        string
                         +--rw os-type?            string
                         +--rw feature*            yang:yang-identifier
                         +--rw deviation* [name revision]
                         |  +--rw name        yang:yang-identifier
                         |  +--rw revision    union
                         +--rw conformance-type?   enumeration

   This sub-tree structure also enables one to look for YANG modules for
   a class of platforms (e.g., list of modules for Cisco, or list of
   modules for Cisco ASR9K routers) instead of only being able to look
   for YANG modules for a specific platform and software release.

2.8.  Regex Expression Differences

   Another challenge encountered when trying to using
   [I-D.openconfig-netmod-model-catalog] as the canonical catalog is the
   regular expression syntax it uses.  The Openconfig module uses a
   POSIX-compliant regular expression syntax whereas YANG-based protocol
   implementations like ConfD [1] expect the IETF-chosen W3C syntax.  In
   order to load the Openconfig catalog in such engines, changes to the
   regular expression syntax had to be done, and these one-off changes
   are not supportable.






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3.  YANG Catalog Use Cases

   The YANG Catalog module is currently targeted to address the
   following use cases.

3.1.  YANG Search Metadata

   The yangcatalog.org toolchain provides a service for searching [2]
   for YANG modules based on keywords.  The resulting search data
   currently stores the module and node metadata in a proprietary format
   along with the search index data.  By populating the yang-catalog
   module, this search service can instead pull the metadata from the
   implementation of the module.  Populating this instance of the yang-
   catalog module will be using an API that is still under development,
   but will ultimately allow SDOs and vendors to provide metadata and
   ensure the search service has the most up-to-date data for all
   available modules.

3.2.  Identify YANG Module Support in Devices

   By organizing the yang-catalog module so that one can either find all
   implementations for a given module, or find all modules supported by
   a vendor platform and software release, the catalog will provide a
   straight-forward way for one to understand the extent of YANG module
   support in participating vendors' software releases.  Eventually a
   web-based graphical interface will be connected to this on
   yangcatalog.org to make it easier for consumers to leverage the
   instance of the yang-catalog module for this use case.

4.  YANG Catalog YANG module

   The structure of the model defined in this document is described by
   the YANG module below.

<CODE BEGINS> file "yang-catalog@2017-07-28.yang"
module yang-catalog {
 namespace "urn:ietf:params:xml:ns:yang:yang-catalog";
 prefix yc;

 import ietf-yang-types {
   prefix yang;
 }

 import ietf-yang-library {
   prefix yanglib;
 }

 import ietf-inet-types {



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  prefix inet;
 }

 organization
   "yangcatalog.org";
 contact
   "Benoit Claise <bclaise@cisco.com>

    Joe Clarke <jclarke@cisco.com>";
 description
   "This module contains metadata pertinent to each YANG module, as
    well as a list of vendor implementations for each module.  The
    structure is laid out in such a way as to make it possible to
    locate metadata and vendor implementation on a per-module basis
    as well as obtain a list of available modules for a given
    vendor's platform and specific software release.";

 revision 2017-07-28 {
   description
     "* Revert config false nodes as we need to be able to set these via <edit-config>

      * Make conformance-type optional as not all vendors implement yang-library

      * Re-add the path typedef";
   reference
     "YANG Catalog <https://yangcatalog.org>";
 }
 revision 2017-07-26 {
   description
     "A number of improvements based on YANG Doctor review:

     * Remove references to 'server' in leafs describing YANG data
     * Fold the augmentation module leafs directly under /catalog/modules/module
     * Use identities for protocols instead of an emumeration
     * Make some extractable fields 'config false'
     * Fix various types
     * Normalize enums to be lowercase
     * Add a leaf for module-classification
     * Change yang-version to be an enum
     * Add module conformance, deviation and feature leafs under the implementation branches";
   reference
     "YANG Catalog <https://yangcatalog.org>";
 }
 revision 2017-07-14 {
   description
     "Modularize some of the leafs and create typedefs so they
      can be shared between the API input modules.";
   reference



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     "YANG Catalog <https://yangcatalog.org>";
 }
 revision 2017-07-03 {
   description
     "Initial revision.";
   reference "
     YANG Catalog <https://yangcatalog.org>";
 }

 /*
  * Identities
  */
 identity protocol {
   description
     "Abstract base identity for a YANG-based protocol.";
 }

 identity netconf {
   base protocol;
   description
     "Protocol identity for NETCONF as described in RFC 6241.";
 }

 identity restconf {
   base protocol;
   description
     "Protocol identity for RESTCONF as described in RFC 8040.";
 }

 /*
  * Typedefs
  */
 typedef email-address {
   type string {
     pattern "[a-zA-Z0-9.!#$%&'*+/=?^_`{|}~-]+@[a-zA-Z0-9-]+([.][a-zA-Z0-9-]+)*";
   }
   description
     "This type represents a string with an email address.";
 }

 typedef path {
   type string {
     pattern '([A-Za-z]:|[\w-]+(\.[\w-]+)*)?(([/\\][\w@.-]+)+)';
   }
   description
     "This type represents a string with path to the file.";
 }




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 container catalog {
   description
     "Root container of yang-catalog holding two main branches -
      modules and vendors. The modules sub-tree contains all the modules in
      the catalog and all of their metadata with their implementations.
      The vendor sub-tree holds modules for specific vendors, platforms,
      software-versions, and software-flavors. It contains reference to a
      name and revision of the module in order to reference the module's full
      set of metadata.";
   container modules {
     description
       "Container holding the list of modules";
     list module {
       key "name revision organization";
       description
         "Each entry represents one revision of one module
          for one organization.";
       uses yang-lib-common-leafs;
       uses yang-lib-schema-leaf;
       uses catalog-module-metadata;
       leaf organization {
         type string;
         description
                "This statement defines the party responsible for this
                 module.  The argument is a string that is used to specify a textual
                 description of the organization(s) under whose auspices this module
                 was developed.";
       }
       uses organization-specific-metadata;
       leaf namespace {
         type inet:uri;
         mandatory true;
         description
           "The XML namespace identifier for this module.";
       }
       list submodule {
         key "name revision";
         description
           "Each entry represents one submodule within the
            parent module.";
         uses yang-lib-common-leafs;
         uses yang-lib-schema-leaf;
       }
       container implementations {
         description
           "Container holding lists of per-module implementation details.";
         list implementation{
           key "vendor platform software-version software-flavor";



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           description
             "List of module implementations.";
           leaf vendor {
             type string;
             description
               "Organization that implements this module.";
           }
           leaf platform {
             type string;
             description
               "Platform on which this module is implemented.";
           }
           leaf software-version {
             type string;
             description
               "Name of the version of software.  With respect to most network device appliances,
                this will be the operating system version.  But for other YANG module
                implementation, this would be a version of appliance software.  Ultimately,
                this should correspond to a version string that will be recognizable by
                the consumers of the platform.";
           }
           leaf software-flavor {
             type string;
             description
               "A variation of a specific version where
                YANG model support may be different.  Depending on the vendor, this could
                be a license, additional software component, or a feature set.";
           }
           uses shared-implementation-leafs;
           uses yang-lib-imlementation-leafs;
         }
       }
     }
   } // end of modules

   container vendors {
     description
       "Container holding lists of organizations that publish YANG modules.";
     list vendor {
       key name;
       description
         "List of organizations publishing YANG modules.";
       leaf name {
         type string;
         description
           "Name of the maintaining organization -- the name should be
            supplied in the official format used by the organization.
            Standards Body examples:



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              IETF, IEEE, MEF, ONF, etc.
            Commercial entity examples:
              AT&T, Facebook, <Vendor>
            Name of industry forum examples:
            OpenConfig, OpenDaylight, ON.Lab";
       }
       container platforms {
         description "Container holding list of platforms.";
         list platform {
           key name;
           description
             "List of platforms under specific vendor";
           leaf name {
             type string;
             description
               "Name of the platform";
           }
           container software-versions {
             description "Container holding list of versions of software versions.";
             list software-version {
               key name;
               description
                 "List of version of software versions under specific vendor, platform.";
               leaf name {
                 type string;
                 description
                   "Name of the version of software.  With respect to most network device appliances,
                    this will be the operating system version.  But for other YANG module
                    implementation, this would be a version of appliance software.  Ultimately,
                    this should correspond to a version string that will be recognizable by
                    the consumers of the platform.";
               }
               container software-flavors {
                 description "Container holding list of software flavors.";
                 list software-flavor {
                   key name;
                   description
                     "List of software flavors under specific vendor, platform, software-version.";
                   leaf name {
                     type string;
                     description
                       "A variation of a specific version where
                        YANG model support may be different.  Depending on the vendor, this could
                        be a license, additional software component, or a feature set.";
                   }
                   container protocols {
                     description
                       "List of the protocols";



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                     list protocol {
                       key name;
                       description
                         "YANG-based protocol that is used on the device.  New identities
                          are expected to be added to address other YANG-based protocols.";
                       leaf name {
                         type identityref {
                           base protocol;
                         }
                         description
                           "Identity of the YANG-based protocol that is supported.";
                       } // end of name
                       leaf protocol-version {
                         type string;
                         description
                           "Version of the specific protocol.";
                       }
                       leaf-list capabilities {
                         type string;
                         description
                           "Listed name of capabilities that are
                            supported by the specific device.";
                       }
                     } // end of protocol
                   } // end of protocols
                   container modules {
                     description
                       "Container holding list of modules.";
                     list module {
                       key "name revision organization";
                       description
                        "List of references to YANG modules under specific vendor, platform, software-version,
                         software-flavor.  Using these references, the complete set of metadata can be
                         retrieved for each module.";
                       leaf name {
                         type leafref {
                           path "/catalog/modules/module/name";
                         }
                         description
                           "Reference to a name of the module that is contained in specific vendor, platform,
                            software-version, software-flavor.";
                       }
                       leaf revision {
                         type leafref {
                           path "/catalog/modules/module/revision";
                         }
                         description
                           "Reference to a revision of the module that is contained in specific vendor,



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                            platform, software-version, software-flavor.";
                       }
                       leaf organization {
                         type leafref {
                           path "/catalog/modules/module/organization";
                         }
                         description
                           "Reference to the authoring organization of the module for the implemented
                             module.";
                       }
                       // XXX: Do we need these here???
                       uses shared-implementation-leafs;
                       uses yang-lib-imlementation-leafs;
                     } // end of list module
                   } // end of container modules
                 } // end of software-flavor
               } // end of software-flavors
             } // end of software-version
           } // end of software-versions
         } // end of platform
       } // end of platforms
     } // end of vendor
   } // end of vendors
 } //end of catalog

 grouping catalog-module-metadata {
   uses shared-module-leafs;
   leaf compilation-status {
     type enumeration {
       enum passed {
         description
           "All compilers were able to compile this YANG module without
            any errors or warnings.";
       }
       enum passed-with-warnings {
         description
           "All compilers were able to compile this YANG module without
            any errors, but at least one of them caught a warning.";
       }
       enum failed {
         description
           "At least one of compilers found an error while
            compiling this YANG module.";
       }
       enum pending {
         description
           "The module was just added to the catalog and compilation testing is still
            in progress.";



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       }
       enum unknown {
         description
           "There is not sufficient information about compilation status.  This Could
            mean compilation crashed causing it not to complete fully.";
       }
     }
     description
       "Status of the module, whether it was possible to compile this YANG module or
        there are still some errors/warnings.";
   }
   leaf compilation-result {
     type string;
     description
       "Result of the compilation explaining specifically what error or warning occurred.
        This is not existing if compilation status is PASSED.";
   }
   leaf prefix {
     type string;
     description
       "Statement of yang that is used to define the prefix associated with
        the module and its namespace. The prefix statement's argument is
        the prefix string that is used as a prefix to access a module. The
        prefix string MAY be used to refer to definitions contained in the
        module, e.g., if:ifName.";
   }
   leaf yang-version {
     type enumeration {
       enum 1.0 {
         description
           "YANG version 1.0 as defined in RFC 6020.";
       }
       enum 1.1 {
         description
           "YANG version 1.1 as defined in RFC 7950.";
       }
     }
     description
       "The optional yang-version statement specifies which version of the
        YANG language was used in developing the module.";
   }
   leaf description {
     type string;
     description
       "This statement takes as an argument a string that
        contains a human-readable textual description of this definition.
        The text is provided in a language (or languages) chosen by the
        module developer; for the sake of interoperability, it is RECOMMENDED



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        to choose a language that is widely understood among the community of
        network administrators who will use the module.";
   }
   leaf contact {
     type string;
     description
       "This statement provides contact information for the module.
        The argument is a string that is used to specify contact information
        for the person or persons to whom technical queries concerning this
        module should be sent, such as their name, postal address, telephone
        number, and electronic mail address.";
   }
   leaf module-type {
     type enumeration {
       enum module {
         description "If YANG file contains module.";
       }
       enum submodule {
         description "If YANG file contains sub-module.";
       }
     }
     description "Whether a file contains a YANG module or sub-module.";
   }
   leaf tree-type {
     type enumeration {
       enum split {
         description
           "This module uses a split config/operational state layout.";
       }
       enum nmda-compatible {
         description
           "This module is compatible with the Network Management Datastores
            Architecture (NMDA) and combines config and operational state nodes.";
       }
       enum transitional-extra {
         description
           "This module is derived as a '-state' module to allow for transitioning
            to a full NMDA-compliant tree structure.";
       }
       enum openconfig {
         description
           "This module uses the Openconfig data element layout.";
       }
       enum unclassified {
        description
          "This module does not have a data element tree, or it does not belong to any category.";
       }
       enum not-applicable {



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         description
           "This module is submodule.";
       }
     }
     description
       "The type of data element tree used by the module as it relates to the
        Network Management Datastores Architecture.";
     reference
       "draft-dsdt-nmda-guidelines Guidelines for YANG Module Authors (NMDA)";
   }
   description
     "Grouping of YANG module metadata that extends the common list defined in the YANG
      Module Library (RFC 7895).";
 }

 grouping organization-specific-metadata {
   container ietf {
     when "../organization = 'ietf'" {
         description
           "Include this container specific metadata of the IETF.";
     }
     leaf ietf-wg {
       type string;
       description
         "Working group that authored the document containing this module.";
     }
     description
       "Include this container for the IETF-specific organization metadata.";
   }
   description
     "Any organization that has some specific metadata of the yang module and want them add to the
      yang-catalog, should augment this grouping. This grouping is for any metadata that can`t be used for
      every yang module.";
 }
 grouping yang-lib-common-leafs {
   leaf name {
     type yang:yang-identifier;
       description
         "The YANG module or submodule name.";
   }
   leaf revision {
     type union {
       type yanglib:revision-identifier;
       type string { length 0; }
     }
     description
       "The YANG module or submodule revision date.
        A zero-length string is used if no revision statement



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        is present in the YANG module or submodule.";
   }
   description
     "The YANG module or submodule revision date.
      A zero-length string is used if no revision statement
      is present in the YANG module or submodule.";
    reference
      "RFC7895 YANG Module Library : common-leafs grouping";
 }
 grouping yang-lib-schema-leaf {
   leaf schema {
      type inet:uri;
      description
        "Contains a URL that represents the YANG schema
         resource for this module or submodule.
         This leaf will only be present if there is a URL
         available for retrieval of the schema for this entry.";
    }
    description
      "These are a subset of leafs from the yang-library (RFC 7895) that provide some
       extractable fields for catalog modules.  The module-list grouping cannot be
       used from yang-library as modules themselves cannot have conformance without
       a server.";
    reference
      "RFC7895 YANG Module Library : schema-leaf grouping";
 }
 grouping yang-lib-imlementation-leafs {
   leaf-list feature {
     type yang:yang-identifier;
     description
      "List of YANG feature names from this module that are
       supported by the server, regardless of whether they are
       defined in the module or any included submodule.";
   }
   list deviation {
     key "name revision";
     description
       "List of YANG deviation module names and revisions
        used by this server to modify the conformance of
        the module associated with this entry.  Note that
        the same module can be used for deviations for
        multiple modules, so the same entry MAY appear
        within multiple 'module' entries.
        The deviation module MUST be present in the 'module'
        list, with the same name and revision values.
        The 'conformance-type' value will be 'implement' for
        the deviation module.";
     uses yang-lib-common-leafs;



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   }
   leaf conformance-type {
     type enumeration {
       enum implement {
         description
           "Indicates that the server implements one or more
            protocol-accessible objects defined in the YANG module
            identified in this entry.  This includes deviation
            statements defined in the module.
            For YANG version 1.1 modules, there is at most one
            module entry with conformance type 'implement' for a
            particular module name, since YANG 1.1 requires that,
            at most, one revision of a module is implemented.
            For YANG version 1 modules, there SHOULD NOT be more
            than one module entry for a particular module name.";
       }
       enum import {
         description
           "Indicates that the server imports reusable definitions
            from the specified revision of the module but does
            not implement any protocol-accessible objects from
            this revision.
            Multiple module entries for the same module name MAY
            exist.  This can occur if multiple modules import the
            same module but specify different revision dates in
            the import statements.";
       }
     }
     // Removing the mandatory true for now as not all vendors may have
     // this information if they do not implement yang-library.
     //mandatory true;
     description
      "Indicates the type of conformance the server is claiming
       for the YANG module identified by this entry.";
   }
   description
     "This is a set of leafs extracted from the yang-library that are
      specific to server implementations.";
   reference
     "RFC7895 YANG Module Library : module-list grouping";
 }
 grouping shared-implementation-leafs {
   leaf os-version {
     type string;
     description
       "Version of the operating system using this module.  This is primarily useful if
        the software implementing the module is an application that requires a specific
        operating system.";



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   }
   leaf feature-set {
     type string;
     description
       "An optional feature of the software that is required in order to implement this
        module.  Some form of this must be incorporated in software-version or
        software-flavor, but can be broken out here for additional clarity.";
   }
   leaf os-type {
     type string;
     description
       "Type of the operating system using this module.  This is primarily useful if
        the software implementing the module is an application that requires a
        specific operating system.";
   }
   description
     "Grouping of non-key leafs to be used in the module and vendor sub-trees.";
 }
 grouping shared-module-leafs {
   leaf generated-from {
     type enumeration {
       enum mib {
         description "Module generated from Structure of Management Information (SMI)
           MIB per RFC6643.";
       }
       enum code {
         description "Module generated automatically from code.";
       }
       enum not-applicable {
         description
           "Module was not generated but it was authored manually.";
       }
       enum native {
         description "Module generated from platform internal or
           proprietary structure.";
       }
     }
     default not-applicable;
     description
       "This statement defines weather the module was generated or not.
        Default value is set to not-applicable, which means that module
        was created manualy and not generated.";
   }
   leaf maturity-level {
     type enumeration {
       enum ratified {
         description
           "Maturity of a module that is fully approved (e.g., a standard).";



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       }
       enum adopted {
         description
           "Maturity of a module that is actively being developed by a organization towards ratification.";
       }
       enum initial {
         description
           "Maturity of a module that has been initially created, but has no official
            organization-level status.";
       }
       enum not-applicable {
         description
           "The maturity level is not used for vendor-supplied models, and thus all vendor
            modules will have a maturity of not-applicable";
       }
     }
     description
       "The current maturity of the module with respect to the body that created it.
        This allows one to understand where the module is in its overall life cycle.";
   }
   leaf document-name {
     type string;
     description
       "The name of the document from which the module was extracted or taken;
        or that provides additional context about the module.";
   }
   leaf author-email {
     type yc:email-address;
     description
       "Contact email of the author who is responsible for this module.";
   }
   leaf reference {
     type inet:uri;
     description
       "A string that is used to specify a textual cross-reference to an external document, either
        another module that defines related management information, or a document that provides
        additional information relevant to this definition.";
   }
   leaf module-classification {
     type enumeration {
       enum network-service {
         description
           "Network Service YANG Module that describes the configuration, state
            data, operations, and notifications of abstract representations of
            services implemented on one or multiple network elements.";
       }
       enum network-element {
         description



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           "Network Element YANG Module that describes the configuration, state
            data, operations, and notifications of specific device-centric
            technologies or features.";
       }
       enum unknown {
         description
           "In case that there is not sufficient information about how to classify the module.";
       }
       enum not-applicable {
         description
           "The YANG module abstraction type is neither a Network Service YANG Module
            nor a Network Element YANG Module.";
       }
     }
     mandatory true;
     description
       "The high-level classification of the given YANG module.";
     reference
       "RFC8199 YANG Module Classification";
   }
   description
     "These leafs are shared among the yang-catalog and its API.";
 }
 grouping online-source-file {
   leaf owner {
     type string;
     mandatory true;
     description
       "Username or ID of the owner of the version control system repository.";
     }
   leaf repository {
     type string;
     mandatory true;
     description
       "The name of the repository.";
   }
   leaf path {
     type path;
     mandatory true;
     description
       "Location within the repository of the module file.";
   }
   leaf branch {
     type string;
     description
       "Revision control system branch or tag to use to find the module.  If this is not
        specified, the head of the repository is used.";
   }



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   description
     "Networked version control system location of the module file.";
 }
}
<CODE ENDS>

5.  Security Considerations

   The goal of the YANG Catalog module and yangcatalog.org is to
   document a large library of YANG modules and their implementations.
   Already, we have seen some SDOs hestitant to provide modules that
   have not reached a "ratified" maturity level because of intellectual
   property leakage concerns or simply organization process that
   mandates only fully ratified modules can be published.  Care must be
   paid that through private automated testing and validation of such
   modules that their metadata does not leak before the publishing
   organization approves the release of such data.

   Similarly, from a vendor implementation standpoint, data that is
   exposed to the catalog before the vendor has fully vetted it could
   cause confusion amongst that vendor's customers or reveal product
   releases to the market before they have been officially announced.

   Ultimately, there is a balance to be struck with respect to providing
   a rich library of YANG module metadata, and doing so at the right
   time to avoid information leakage.

6.  IANA Considerations

   No IANA action is requested.

7.  References

7.1.  Normative References

   [RFC6020]  Bjorklund, M., Ed., "YANG - A Data Modeling Language for
              the Network Configuration Protocol (NETCONF)", RFC 6020,
              DOI 10.17487/RFC6020, October 2010,
              <http://www.rfc-editor.org/info/rfc6020>.

   [RFC7895]  Bierman, A., Bjorklund, M., and K. Watsen, "YANG Module
              Library", RFC 7895, DOI 10.17487/RFC7895, June 2016,
              <http://www.rfc-editor.org/info/rfc7895>.

   [RFC7950]  Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
              RFC 7950, DOI 10.17487/RFC7950, August 2016,
              <http://www.rfc-editor.org/info/rfc7950>.




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7.2.  Informative References

   [I-D.ietf-netmod-revised-datastores]
              Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
              and R. Wilton, "Network Management Datastore
              Architecture", draft-ietf-netmod-revised-datastores-03
              (work in progress), July 2017.

   [I-D.ietf-netmod-yang-model-classification]
              Bogdanovic, D., Claise, B., and C. Moberg, "YANG Module
              Classification", draft-ietf-netmod-yang-model-
              classification-08 (work in progress), June 2017.

   [I-D.openconfig-netmod-model-catalog]
              Shaikh, A., Shakir, R., and K. D'Souza, "Catalog and
              registry for YANG models", draft-openconfig-netmod-model-
              catalog-02 (work in progress), March 2017.

7.3.  URIs

   [1] https://developer.cisco.com/site/confD/index.gsp

   [2] https://yangcatalog.org/yang-search

Appendix A.  Acknowledgments

   The authors would like to thanks Miroslav Kovac for this help on this
   YANG module and the yangcatalog.org implementation.  We would also
   like to thank Radek Krejci for his extensive review and suggestions
   for improvement.

   The RFC text was produced using Marshall Rose's xml2rfc tool.



















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Appendix B.  Changes From Previous Revisions

   RFC Editor to remove this section prior to publication.

   Draft -00 to -01:

   o  Redesign of module sub-tree based on review.

   o  Modularize some leafs and create typedefs to share with API YANG
      modules.

   o  Add module conformance-type, deviation and feature leafs under the
      implementation branch.

   o  Change yang-version to be an enum.

   o  Add a leaf for module-classification based on
      [I-D.ietf-netmod-yang-model-classification].

   o  Normalize enums to be lowercase.

   o  Use identities for protocols instead of an enumeration.

   o  Make conformance-type optional as not all vendors implement
      [RFC7895].

   o  Add a leaf for tree-type based on
      [I-D.ietf-netmod-revised-datastores].

   o  Add a reference to contributing to the YANG Catalog at
      yangcatalog.org.

   o  Various wording and style changes to the document text.

Authors' Addresses

   Joe Clarke
   Cisco Systems, Inc.
   7200-12 Kit Creek Rd
   Research Triangle Park, North Carolina
   United States of America

   Phone: +1-919-392-2867
   Email: jclarke@cisco.com







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   Benoit Claise
   Cisco Systems, Inc.
   De Kleetlaan 6a b1
   1831 Diegem
   Belgium

   Phone: +32 2 704 5622
   Email: bclaise@cisco.com











































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