Grammar for Enterprise YANG Module Namespace
draft-chen-netmod-enterprise-yang-namespace-00

Internet Draft                                                   I. Chen
<draft-chen-netmod-enterprise-yang-namespace-00.txt>            Ericsson
Category: Informational
Expires in 6 months                                     October 16, 2015

              Grammar for Enterprise YANG Module Namespace
          <draft-chen-netmod-enterprise-yang-namespace-00.txt>

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Abstract

   This document defines the grammar to create enterprise YANG module
   namespaces that are globally unique, as required by the YANG modeling
   language.

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Table of Contents

   1. Introduction ....................................................3
     1.1. Terminology .................................................3
   2. YANG Module Namespace Requirements and Recommendations ..........3
   3. Enterprise YANG Module Namespace Grammar ........................4
   4. Usage Example ...................................................4
   5. IANA Considerations .............................................5
   6. Security Considerations .........................................5
   7. References ......................................................5

1. Introduction

   The use of a standard data modeling language YANG [RFC6020] together
   with Network Configuration Protocol (NETCONF) [RFC6241] allows for
   the creation of a standard network configuration interface.  YANG
   further allows vendors to customize standard YANG modules and to
   create enterprise YANG modules that adapt standard YANG modules to
   different devices and features.  To identify YANG modules, [RFC6020]
   requires YANG module namespaces of all YANG modules, both standard
   YANG modules and enterprise YANG modules, be globally unique.
   [RFC6020] also recommends that enterprise YANG modules have module
   names that are globally unique.

   Based the module naming convention recommended in [RFC6020], this
   document defines the grammar to create YANG module namespaces for
   enterprise YANG modules that result in globally unique namespaces.

1.1.   Terminology

   The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14, [RFC2119].

2.  YANG Module Name and Namespace Requirements and Recommendations

   [RFC6020] consists of several YANG module name and namespace
   requirements and recommendations.

   [RFC6020] Section 5.1 paragraph 3 states that

      The names of all standard modules and submodules MUST be unique.
      Developers of enterprise modules are RECOMMENDED to choose names
      for their modules that will have a low probability of colliding
      with standard or other enterprise modules, e.g., by using the
      enterprise or organization name as a prefix for the module name.

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   [RFC6020] Section 5.3 paragraph 3 states that

      Namespaces for private modules are assigned by the organization
      owning the module without a central registry.  Namespace URIs MUST
      be chosen so they cannot collide with standard or other enterprise
      namespaces, for example by using the enterprise or organization
      name in the namespace.

   [RFC6020] Section 6.2.1 paragraph 1 states that

      Each identifier is valid in a namespace that depends on the type
      of the YANG item being defined.  All identifiers defined in a
      namespace MUST be unique.

      o  All module and submodule names share the same global module
         identifier namespace.

   The requirement in [RFC6020] Section 6.2.1 means that even enterprise
   YANG module names must be globally unique.  The recommendation in
   [RFC6020] Section 5.1 means that it is desirable to define enterprise
   YANG modules names to use an organization's name as a prefix.

3.  Enterprise YANG Module Namespace Grammar

   This section defines the grammar to create globally unique enterprise
   YANG module namespaces.  The grammar defines a namespace to be a
   Uniform Resource Name (URN) composed of an organization's reverse
   registered domain name, followed by optional sub-domain hierarchies,
   and ending with the module name with the organization's name as the
   prefix.

   <namespace> = urn:<reverse-dns>:<sub-domain><module-name>

   <reverse-dns> = An organization's registered domain name in reverse

   <sub-domain> = Empty string or
                  additional levels of hierarchy defined within a domain
                  in which each level is delimited by colons

   <module-name> = <organization-prefix>-<function>

   <function> = A string that describes the function provided by the
                YANG module

4.  Usage Example

   Suppose a vendor has a registered domain name "example.com".  This
   vendor has also chosen to place all of its YANG modules under the

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   "yang" sub-domain.  Following the enterprise YANG module namespace
   grammar described in this document, the vendor ends up with the
   patterns below.

   <reverse-dns> = com:example
   <sub-domain> = yang
   <namespace> = urn:com:example:yang:<module-name>
   <module-name> = example-<function>

   As a result, this vendor's OSPF YANG module has the namespace
   "urn:com:example:yang:example-ospf".

5.  Security Considerations

   TBD.

6.  IANA Considerations

   TBD.  Is it necessary to include a reference to the top-level "com"
   registry RFC?

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>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, DOI
              10.17487/RFC2119, March 1997, <http://www.rfc-
              editor.org/info/rfc2119>.

7.2.  Informative References

   [RFC6241]  Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
              and A.  Bierman, Ed., "Network Configuration Protocol
              (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
              <http://www.rfc-editor.org/info/rfc6241>.

Author's Address

   I. Chen
   ing-wher.chen@ericsson.com

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