draft-ietf-netmod-yang-usage-11.txt   rfc6087.txt 
Internet Engineering Task Force A. Bierman Internet Engineering Task Force (IETF) A. Bierman
Internet-Draft Brocade Request for Comments: 6087 Brocade
Intended status: Informational October 2, 2010 Category: Informational January 2011
Expires: April 5, 2011 ISSN: 2070-1721
Guidelines for Authors and Reviewers of YANG Data Model Documents Guidelines for Authors and Reviewers of YANG Data Model Documents
draft-ietf-netmod-yang-usage-11
Abstract Abstract
This memo provides guidelines for authors and reviewers of standards This memo provides guidelines for authors and reviewers of Standards
track specifications containing YANG data model modules. Applicable Track specifications containing YANG data model modules. Applicable
portions may be used as a basis for reviews of other YANG data model portions may be used as a basis for reviews of other YANG data model
documents. Recommendations and procedures are defined, which are documents. Recommendations and procedures are defined, which are
intended to increase interoperability and usability of Network intended to increase interoperability and usability of Network
Configuration Protocol (NETCONF) implementations which utilize YANG Configuration Protocol (NETCONF) implementations that utilize YANG
data model modules. data model modules.
Status of this Memo Status of This Memo
This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering This document is not an Internet Standards Track specification; it is
Task Force (IETF). Note that other groups may also distribute published for informational purposes.
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 This document is a product of the Internet Engineering Task Force
and may be updated, replaced, or obsoleted by other documents at any (IETF). It represents the consensus of the IETF community. It has
time. It is inappropriate to use Internet-Drafts as reference received public review and has been approved for publication by the
material or to cite them other than as "work in progress." Internet Engineering Steering Group (IESG). Not all documents
approved by the IESG are a candidate for any level of Internet
Standard; see Section 2 of RFC 5741.
This Internet-Draft will expire on April 5, 2011. Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc6087.
Copyright Notice Copyright Notice
Copyright (c) 2010 IETF Trust and the persons identified as the Copyright (c) 2011 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. Requirements Notation . . . . . . . . . . . . . . . . . . 5 2.1. Requirements Notation . . . . . . . . . . . . . . . . . . 3
2.2. NETCONF Terms . . . . . . . . . . . . . . . . . . . . . . 5 2.2. NETCONF Terms . . . . . . . . . . . . . . . . . . . . . . 4
2.3. YANG Terms . . . . . . . . . . . . . . . . . . . . . . . . 5 2.3. YANG Terms . . . . . . . . . . . . . . . . . . . . . . . . 4
2.4. Terms . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.4. Terms . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. General Documentation Guidelines . . . . . . . . . . . . . . . 7 3. General Documentation Guidelines . . . . . . . . . . . . . . . 5
3.1. Module Copyright . . . . . . . . . . . . . . . . . . . . . 7 3.1. Module Copyright . . . . . . . . . . . . . . . . . . . . . 5
3.2. Narrative Sections . . . . . . . . . . . . . . . . . . . . 8 3.2. Narrative Sections . . . . . . . . . . . . . . . . . . . . 6
3.3. Definitions Section . . . . . . . . . . . . . . . . . . . 8 3.3. Definitions Section . . . . . . . . . . . . . . . . . . . 6
3.4. Security Considerations Section . . . . . . . . . . . . . 8 3.4. Security Considerations Section . . . . . . . . . . . . . 6
3.5. IANA Considerations Section . . . . . . . . . . . . . . . 9 3.5. IANA Considerations Section . . . . . . . . . . . . . . . 7
3.5.1. Documents that Create a New Name Space . . . . . . . . 9 3.5.1. Documents that Create a New Namespace . . . . . . . . 7
3.5.2. Documents that Extend an Existing Name Space . . . . . 9 3.5.2. Documents that Extend an Existing Namespace . . . . . 8
3.6. Reference Sections . . . . . . . . . . . . . . . . . . . . 10 3.6. Reference Sections . . . . . . . . . . . . . . . . . . . . 8
4. YANG Usage Guidelines . . . . . . . . . . . . . . . . . . . . 11 4. YANG Usage Guidelines . . . . . . . . . . . . . . . . . . . . 8
4.1. Module Naming Conventions . . . . . . . . . . . . . . . . 11 4.1. Module Naming Conventions . . . . . . . . . . . . . . . . 8
4.2. Identifiers . . . . . . . . . . . . . . . . . . . . . . . 11 4.2. Identifiers . . . . . . . . . . . . . . . . . . . . . . . 9
4.3. Defaults . . . . . . . . . . . . . . . . . . . . . . . . . 11 4.3. Defaults . . . . . . . . . . . . . . . . . . . . . . . . . 9
4.4. Conditional Statements . . . . . . . . . . . . . . . . . . 12 4.4. Conditional Statements . . . . . . . . . . . . . . . . . . 10
4.5. XPath Usage . . . . . . . . . . . . . . . . . . . . . . . 12 4.5. XPath Usage . . . . . . . . . . . . . . . . . . . . . . . 10
4.6. Lifecycle Management . . . . . . . . . . . . . . . . . . . 13 4.6. Lifecycle Management . . . . . . . . . . . . . . . . . . . 11
4.7. Module Header, Meta, and Revision Statements . . . . . . . 14 4.7. Module Header, Meta, and Revision Statements . . . . . . . 12
4.8. Namespace Assignments . . . . . . . . . . . . . . . . . . 15 4.8. Namespace Assignments . . . . . . . . . . . . . . . . . . 13
4.9. Top Level Data Definitions . . . . . . . . . . . . . . . . 16 4.9. Top-Level Data Definitions . . . . . . . . . . . . . . . . 14
4.10. Data Types . . . . . . . . . . . . . . . . . . . . . . . . 16 4.10. Data Types . . . . . . . . . . . . . . . . . . . . . . . . 14
4.11. Reusable Type Definitions . . . . . . . . . . . . . . . . 17 4.11. Reusable Type Definitions . . . . . . . . . . . . . . . . 15
4.12. Data Definitions . . . . . . . . . . . . . . . . . . . . . 18 4.12. Data Definitions . . . . . . . . . . . . . . . . . . . . . 15
4.13. Operation Definitions . . . . . . . . . . . . . . . . . . 19 4.13. Operation Definitions . . . . . . . . . . . . . . . . . . 17
4.14. Notification Definitions . . . . . . . . . . . . . . . . . 19 4.14. Notification Definitions . . . . . . . . . . . . . . . . . 17
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 20 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17
6. Security Considerations . . . . . . . . . . . . . . . . . . . 21 6. Security Considerations . . . . . . . . . . . . . . . . . . . 18
6.1. Security Considerations Section Template . . . . . . . . . 21 6.1. Security Considerations Section Template . . . . . . . . . 19
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 24 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 20
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 25 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 20
8.1. Normative References . . . . . . . . . . . . . . . . . . . 25 8.1. Normative References . . . . . . . . . . . . . . . . . . . 20
8.2. Informative References . . . . . . . . . . . . . . . . . . 25 8.2. Informative References . . . . . . . . . . . . . . . . . . 21
Appendix A. Module Review Checklist . . . . . . . . . . . . . . . 27 Appendix A. Module Review Checklist . . . . . . . . . . . . . . . 22
Appendix B. YANG Module Template . . . . . . . . . . . . . . . . 29 Appendix B. YANG Module Template . . . . . . . . . . . . . . . . 24
Appendix C. Change Log . . . . . . . . . . . . . . . . . . . . . 32
C.1. Changes from 10 to 11 . . . . . . . . . . . . . . . . . . 32
C.2. Changes from 09 to 10 . . . . . . . . . . . . . . . . . . 32
C.3. Changes from 08 to 09 . . . . . . . . . . . . . . . . . . 32
C.4. Changes from 07 to 08 . . . . . . . . . . . . . . . . . . 32
C.5. Changes from 06 to 07 . . . . . . . . . . . . . . . . . . 32
C.6. Changes from 05 to 06 . . . . . . . . . . . . . . . . . . 32
C.7. Changes from 04 to 05 . . . . . . . . . . . . . . . . . . 33
C.8. Changes from 03 to 04 . . . . . . . . . . . . . . . . . . 33
C.9. Changes from 02 to 03 . . . . . . . . . . . . . . . . . . 34
C.10. Changes from 01 to 02 . . . . . . . . . . . . . . . . . . 34
C.11. Changes from 00 to 01 . . . . . . . . . . . . . . . . . . 34
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 36
1. Introduction 1. Introduction
The standardization of network configuration interfaces for use with The standardization of network configuration interfaces for use with
the Network Configuration Protocol (NETCONF) [RFC4741] requires a the Network Configuration Protocol (NETCONF) [RFC4741] requires a
modular set of data models, which can be reused and extended over modular set of data models, which can be reused and extended over
time. time.
This document defines a set of usage guidelines for standards track This document defines a set of usage guidelines for Standards Track
documents containing YANG [I-D.ietf-netmod-yang] data models. YANG documents containing YANG [RFC6020] data models. YANG is used to
is used to define the data structures, protocol operations, and define the data structures, protocol operations, and notification
notification content used within a NETCONF server. A server which content used within a NETCONF server. A server that supports a
supports a particular YANG module will support client NETCONF particular YANG module will support client NETCONF operation
operation requests, as indicated by the specific content defined in requests, as indicated by the specific content defined in the YANG
the YANG module. module.
This document is similar to the SMIv2 usage guidelines specification This document is similar to the Structure of Management Information
[RFC4181] in intent and structure. However, since that document was version 2 (SMIv2) usage guidelines specification [RFC4181] in intent
written a decade after SMIv2 modules had been in use, it was and structure. However, since that document was written a decade
published as a 'best current practice' (BCP). This document is not a after SMIv2 modules had been in use, it was published as a 'Best
BCP, but rather an informational reference, intended to promote Current Practice' (BCP). This document is not a BCP, but rather an
consistency in documents containing YANG modules. informational reference, intended to promote consistency in documents
containing YANG modules.
Many YANG constructs are defined as optional to use, such as the Many YANG constructs are defined as optional to use, such as the
description statement. However, in order to maximize description statement. However, in order to maximize
interoperability of NETCONF implementations utilizing YANG data interoperability of NETCONF implementations utilizing YANG data
models, it is desirable to define a set of usage guidelines which may models, it is desirable to define a set of usage guidelines that may
require a higher level of compliance than the minimum level defined require a higher level of compliance than the minimum level defined
in the YANG specification. in the YANG specification.
In addition, YANG allows constructs such as infinite length In addition, YANG allows constructs such as infinite length
identifiers and string values, or top-level mandatory nodes, that a identifiers and string values, or top-level mandatory nodes, that a
compliant server is not required to support. Only constructs which compliant server is not required to support. Only constructs that
all servers are required to support can be used in IETF YANG modules. all servers are required to support can be used in IETF YANG modules.
This document defines usage guidelines related to the NETCONF This document defines usage guidelines related to the NETCONF
operations layer, and NETCONF content layer, as defined in [RFC4741]. operations layer and NETCONF content layer, as defined in [RFC4741].
These guidelines are intended to be used by authors and reviewers to These guidelines are intended to be used by authors and reviewers to
improve the readability and interoperability of published YANG data improve the readability and interoperability of published YANG data
models. models.
2. Terminology 2. Terminology
2.1. Requirements Notation 2.1. Requirements Notation
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
skipping to change at page 5, line 33 skipping to change at page 4, line 25
o capabilities o capabilities
o client o client
o operation o operation
o server o server
2.3. YANG Terms 2.3. YANG Terms
The following terms are defined in [I-D.ietf-netmod-yang] and are not The following terms are defined in [RFC6020] and are not redefined
redefined here: here:
o data node o data node
o module o module
o namespace o namespace
o submodule o submodule
o version o version
o YANG o YANG
o YIN o YIN
Note that the term 'module' may be used as a generic term for a YANG Note that the term 'module' may be used as a generic term for a YANG
module or submodule. When describing properties which are specific module or submodule. When describing properties that are specific to
to submodules, the term 'submodule' is used instead. submodules, the term 'submodule' is used instead.
2.4. Terms 2.4. Terms
The following terms are used throughout this document: The following terms are used throughout this document:
published: A stable release of a module or submodule, usually published: A stable release of a module or submodule, usually
contained in an RFC. contained in an RFC.
unpublished: An unstable release of a module or submodule, usually unpublished: An unstable release of a module or submodule, usually
contained in an Internet-Draft. contained in an Internet-Draft.
3. General Documentation Guidelines 3. General Documentation Guidelines
YANG data model modules under review are likely to be contained in YANG data model modules under review are likely to be contained in
Internet-Drafts. All guidelines for Internet-Draft authors MUST be Internet-Drafts. All guidelines for Internet-Draft authors MUST be
followed. These guidelines are defined in [RFC2223] and updated in followed. The RFC Editor provides guidelines for authors of RFCs,
[RFC5741]. Additional information is also available online at: which are first published as Internet-Drafts. These guidelines
should be followed and are defined in [RFC2223] and updated in
http://www.rfc-editor.org/rfc-editor/instructions2authors.txt [RFC5741] and "RFC Document Style" [RFC-STYLE].
The following sections MUST be present in an Internet-Draft The following sections MUST be present in an Internet-Draft
containing a module: containing a module:
o Narrative sections o Narrative sections
o Definitions section o Definitions section
o Security Considerations section o Security Considerations section
o IANA Considerations section o IANA Considerations section
o References section o References section
3.1. Module Copyright 3.1. Module Copyright
The module description statement MUST contain a reference to the The module description statement MUST contain a reference to the
latest approved IETF Trust Copyright statement, which is available latest approved IETF Trust Copyright statement, which is available
on-line at: online at:
http://trustee.ietf.org/license-info/ http://trustee.ietf.org/license-info/
Each YANG module or submodule contained within an Internet-Draft or Each YANG module or submodule contained within an Internet-Draft or
RFC is considered to be a code component. The strings '<CODE RFC is considered to be a code component. The strings '<CODE
BEGINS>' and '<CODE ENDS>' MUST be used to identify each code BEGINS>' and '<CODE ENDS>' MUST be used to identify each code
component. component.
The '<CODE BEGINS>' tag SHOULD be followed by a string identifying The '<CODE BEGINS>' tag SHOULD be followed by a string identifying
the file name specified in section 5.2 of [I-D.ietf-netmod-yang]. the file name specified in Section 5.2 of [RFC6020]. The following
The following example is for the '2010-01-18' revision of the 'ietf- example is for the '2010-01-18' revision of the 'ietf-foo' module:
foo' module:
<CODE BEGINS> file "ietf-foo@2010-01-18.yang" <CODE BEGINS> file "ietf-foo@2010-01-18.yang"
module ietf-foo { module ietf-foo {
// ... // ...
revision 2010-01-18 { revision 2010-01-18 {
description "Latest revision"; description "Latest revision";
reference "RFC XXXXX"; reference "RFC XXXX";
} }
// ... // ...
} }
<CODE ENDS> <CODE ENDS>
Figure 1
3.2. Narrative Sections 3.2. Narrative Sections
The narrative part MUST include an overview section that describes The narrative part MUST include an overview section that describes
the scope and field of application of the module(s) defined by the the scope and field of application of the module(s) defined by the
specification and that specifies the relationship (if any) of these specification and that specifies the relationship (if any) of these
modules to other standards, particularly to standards containing modules to other standards, particularly to standards containing
other YANG modules. The narrative part SHOULD include one or more other YANG modules. The narrative part SHOULD include one or more
sections to briefly describe the structure of the modules defined in sections to briefly describe the structure of the modules defined in
the specification. the specification.
If the module(s) defined by the specification import definitions from If the module(s) defined by the specification imports definitions
other modules (except for those defined in the YANG from other modules (except for those defined in the YANG [RFC6020] or
[I-D.ietf-netmod-yang] or YANG Types [I-D.ietf-netmod-yang-types] YANG Types [RFC6021] documents), or are always implemented in
documents), or are always implemented in conjunction with other conjunction with other modules, then those facts MUST be noted in the
modules, then those facts MUST be noted in the overview section, as overview section, as MUST be noted any special interpretations of
MUST be noted any special interpretations of definitions in other definitions in other modules.
modules.
3.3. Definitions Section 3.3. Definitions Section
This section contains the module(s) defined by the specification. This section contains the module(s) defined by the specification.
These modules MUST be written using the YANG syntax defined in These modules MUST be written using the YANG syntax defined in
[I-D.ietf-netmod-yang]. A YIN syntax version of the module MAY also [RFC6020]. A YIN syntax version of the module MAY also be present in
be present in the document. There MAY also be other types of modules the document. There MAY also be other types of modules present in
present in the document, such as SMIv2, which are not affected by the document, such as SMIv2, which are not affected by these
these guidelines. guidelines.
See Section 4 for guidelines on YANG usage. See Section 4 for guidelines on YANG usage.
3.4. Security Considerations Section 3.4. Security Considerations Section
Each specification that defines one or more modules MUST contain a Each specification that defines one or more modules MUST contain a
section that discusses security considerations relevant to those section that discusses security considerations relevant to those
modules. This section MUST be patterned after the latest approved modules.
template (available at
This section MUST be patterned after the latest approved template
(available at
http://www.ops.ietf.org/netconf/yang-security-considerations.txt). http://www.ops.ietf.org/netconf/yang-security-considerations.txt).
Section 6.1 contains the security considerations template dated
2010-06-16. Authors MUST check the webpage at the URL listed above
in case there is a more recent version available.
In particular: In particular:
o Writable data nodes that could be especially disruptive if abused o Writable data nodes that could be especially disruptive if abused
MUST be explicitly listed by name and the associated security MUST be explicitly listed by name and the associated security
risks MUST be explained. risks MUST be explained.
o Readable data nodes that contain especially sensitive information o Readable data nodes that contain especially sensitive information
or that raise significant privacy concerns MUST be explicitly or that raise significant privacy concerns MUST be explicitly
listed by name and the reasons for the sensitivity/privacy listed by name and the reasons for the sensitivity/privacy
concerns MUST be explained. concerns MUST be explained.
o Operations (i.e., YANG 'rpc' statements) which are potentially o Operations (i.e., YANG 'rpc' statements) that are potentially
harmful to system behavior or that raise significant privacy harmful to system behavior or that raise significant privacy
concerns MUST be explicitly listed by name and the reasons for the concerns MUST be explicitly listed by name and the reasons for the
sensitivity/privacy concerns MUST be explained. sensitivity/privacy concerns MUST be explained.
3.5. IANA Considerations Section 3.5. IANA Considerations Section
In order to comply with IESG policy as set forth in In order to comply with IESG policy as set forth in
http://www.ietf.org/ID-Checklist.html, every Internet-Draft that is http://www.ietf.org/id-info/checklist.html, every Internet-Draft that
submitted to the IESG for publication which has action items for IANA is submitted to the IESG for publication MUST contain an IANA
MUST contain an IANA Considerations section. The requirements for Considerations section. The requirements for this section vary
this section vary depending what actions are required of the IANA. depending on what actions are required of the IANA. If there are no
If there are no IANA considerations applicable to the document, then IANA considerations applicable to the document, then the IANA
the IANA Considerations section is not required. Refer to the Considerations section stating that there are no actions is removed
guidelines in [RFC5226] for more details. by the RFC Editor before publication. Refer to the guidelines in
[RFC5226] for more details.
3.5.1. Documents that Create a New Name Space 3.5.1. Documents that Create a New Namespace
If an Internet-Draft defines a new name space that is to be If an Internet-Draft defines a new namespace that is to be
administered by the IANA, then the document MUST include an IANA administered by the IANA, then the document MUST include an IANA
Considerations section, that specifies how the name space is to be Considerations section that specifies how the namespace is to be
administered. administered.
Specifically, if any YANG module namespace statement value contained Specifically, if any YANG module namespace statement value contained
in the document is not already registered with IANA, then a new YANG in the document is not already registered with IANA, then a new YANG
Namespace registry entry MUST be requested from the IANA. The YANG Namespace registry entry MUST be requested from the IANA. The YANG
[I-D.ietf-netmod-yang] specification includes the procedure for this [RFC6020] specification includes the procedure for this purpose in
purpose in its IANA Considerations section. its IANA Considerations section.
3.5.2. Documents that Extend an Existing Name Space 3.5.2. Documents that Extend an Existing Namespace
It is possible to extend an existing namespace using a YANG submodule It is possible to extend an existing namespace using a YANG submodule
which belongs to an existing module already administered by IANA. In that belongs to an existing module already administered by IANA. In
this case, the document containing the main module MUST be updated to this case, the document containing the main module MUST be updated to
use the latest revision of the submodule. use the latest revision of the submodule.
3.6. Reference Sections 3.6. Reference Sections
For every import or include statement which appears in a module For every import or include statement that appears in a module
contained in the specification, which identifies a module in a contained in the specification, which identifies a module in a
separate document, a corresponding normative reference to that separate document, a corresponding normative reference to that
document MUST appear in the Normative References section. The document MUST appear in the Normative References section. The
reference MUST correspond to the specific module version actually reference MUST correspond to the specific module version actually
used within the specification. used within the specification.
For every normative reference statement which appears in a module For every normative reference statement that appears in a module
contained in the specification, which identifies a separate document, contained in the specification, which identifies a separate document,
a corresponding normative reference to that document SHOULD appear in a corresponding normative reference to that document SHOULD appear in
the Normative References section. The reference SHOULD correspond to the Normative References section. The reference SHOULD correspond to
the specific document version actually used within the specification. the specific document version actually used within the specification.
If the reference statement identifies an informative reference, which If the reference statement identifies an informative reference, which
identifies a separate document, a corresponding informative reference identifies a separate document, a corresponding informative reference
to that document MAY appear in the Informative References section. to that document MAY appear in the Informative References section.
4. YANG Usage Guidelines 4. YANG Usage Guidelines
In general, modules in IETF standards-track specifications MUST In general, modules in IETF Standards Track specifications MUST
comply with all syntactic and semantic requirements of YANG. comply with all syntactic and semantic requirements of YANG
[I-D.ietf-netmod-yang]. The guidelines in this section are intended [RFC6020]. The guidelines in this section are intended to supplement
to supplement the YANG specification, which is intended to define a the YANG specification, which is intended to define a minimum set of
minimum set of conformance requirements. conformance requirements.
In order to promote interoperability and establish a set of practices In order to promote interoperability and establish a set of practices
based on previous experience, the following sections establish usage based on previous experience, the following sections establish usage
guidelines for specific YANG constructs. guidelines for specific YANG constructs.
Only guidelines which clarify or restrict the minimum conformance Only guidelines that clarify or restrict the minimum conformance
requirements are included here. requirements are included here.
4.1. Module Naming Conventions 4.1. Module Naming Conventions
Modules contained in standards track documents SHOULD be named Modules contained in Standards Track documents SHOULD be named
according to the guidelines in the IANA considerations section of according to the guidelines in the IANA Considerations section of
[I-D.ietf-netmod-yang]. [RFC6020].
A distinctive word or acronym (e.g., protocol name or working group A distinctive word or acronym (e.g., protocol name or working group
acronym) SHOULD be used in the module name. If new definitions are acronym) SHOULD be used in the module name. If new definitions are
being defined to extend one or more existing modules, then the same being defined to extend one or more existing modules, then the same
word or acronym should be reused, instead of creating a new one. word or acronym should be reused, instead of creating a new one.
All published module names MUST be unique. For a YANG module All published module names MUST be unique. For a YANG module
published in an RFC, this uniqueness is guaranteed by IANA. For published in an RFC, this uniqueness is guaranteed by IANA. For
unpublished modules, the authors need to check that no other work in unpublished modules, the authors need to check that no other work in
progress is using the same module name. progress is using the same module name.
Once a module name is published, it MUST NOT be reused, even if the Once a module name is published, it MUST NOT be reused, even if the
RFC containing the module is reclassified to 'Historic' status. RFC containing the module is reclassified to 'Historic' status.
4.2. Identifiers 4.2. Identifiers
Identifiers for all YANG identifiers in published modules MUST be Identifiers for all YANG identifiers in published modules MUST be
between 1 and 64 characters in length. These include any construct between 1 and 64 characters in length. These include any construct
specified as an 'identifier-arg-str' token in the ABNF in section 12 specified as an 'identifier-arg-str' token in the ABNF in Section 12
of [I-D.ietf-netmod-yang]. of [RFC6020].
4.3. Defaults 4.3. Defaults
In general, it is suggested that sub-statements containing very In general, it is suggested that substatements containing very common
common default values SHOULD NOT be present. The following sub- default values SHOULD NOT be present. The following substatements
statements are commonly used with the default value, which would make are commonly used with the default value, which would make the module
the module difficult to read if used everywhere they are allowed. difficult to read if used everywhere they are allowed.
+---------------+---------------+ +---------------+---------------+
| Statement | Default Value | | Statement | Default Value |
+---------------+---------------+ +---------------+---------------+
| config | true | | config | true |
| | | | | |
| mandatory | false | | mandatory | false |
| | | | | |
| max-elements | unbounded | | max-elements | unbounded |
| | | | | |
skipping to change at page 13, line 21 skipping to change at page 10, line 52
ordered 'list' or 'leaf-list'. ordered 'list' or 'leaf-list'.
The 'preceding', and 'following' axes SHOULD NOT be used. These The 'preceding', and 'following' axes SHOULD NOT be used. These
constructs rely on XML document order within a NETCONF server constructs rely on XML document order within a NETCONF server
configuration database, which may not be supported consistently or configuration database, which may not be supported consistently or
produce reliable results across implementations. Predicate produce reliable results across implementations. Predicate
expressions based on static node properties (e.g., element name or expressions based on static node properties (e.g., element name or
value, 'ancestor' or 'descendant' axes) SHOULD be used instead. The value, 'ancestor' or 'descendant' axes) SHOULD be used instead. The
'preceding' and 'following' axes MAY be used if document order is not 'preceding' and 'following' axes MAY be used if document order is not
relevant to the outcome of the expression (e.g., check for global relevant to the outcome of the expression (e.g., check for global
uniqueness of a parameter value.) uniqueness of a parameter value).
The 'preceding-sibling' and 'following-sibling' axes SHOULD NOT used. The 'preceding-sibling' and 'following-sibling' axes SHOULD NOT used.
A server is only required to maintain the relative XML document order A server is only required to maintain the relative XML document order
of all instances of a particular user-ordered list or leaf-list. The of all instances of a particular user-ordered list or leaf-list. The
'preceding-sibling' and 'following-sibling' axes MAY be used if they 'preceding-sibling' and 'following-sibling' axes MAY be used if they
are evaluated in a context where the context node is a user-ordered are evaluated in a context where the context node is a user-ordered
'list' or 'leaf-list'. 'list' or 'leaf-list'.
Data nodes which use the 'int64' and 'uint64' built-in type SHOULD Data nodes that use the 'int64' and 'uint64' built-in type SHOULD NOT
NOT be used within numeric expressions. There are boundary be used within numeric expressions. There are boundary conditions in
conditions in which the translation from the YANG 64-bit type to an which the translation from the YANG 64-bit type to an XPath number
XPath number can cause incorrect results. Specifically, an XPath can cause incorrect results. Specifically, an XPath 'double'
'double' precision floating point number cannot represent very large precision floating point number cannot represent very large positive
positive or negative 64-bit numbers because it only provides a total or negative 64-bit numbers because it only provides a total precision
precision of 53 bits. The 'int64' and 'uint64' data types MAY be of 53 bits. The 'int64' and 'uint64' data types MAY be used in
used in numeric expressions if the value can be represented with no numeric expressions if the value can be represented with no more than
more than 53 bits of precision. 53 bits of precision.
Data modelers need to be careful not to confuse the YANG value space Data modelers need to be careful not to confuse the YANG value space
and the XPath value space. The data types are not the same in both, and the XPath value space. The data types are not the same in both,
and conversion between YANG and XPath data types SHOULD be considered and conversion between YANG and XPath data types SHOULD be considered
carefully. carefully.
Explicit XPath data type conversions MAY be used (e.g., 'string', Explicit XPath data type conversions MAY be used (e.g., 'string',
'boolean', or 'number' functions), instead of implicit XPath data 'boolean', or 'number' functions), instead of implicit XPath data
type conversions. type conversions.
skipping to change at page 14, line 11 skipping to change at page 11, line 42
The status statement MUST be present if its value is 'deprecated' or The status statement MUST be present if its value is 'deprecated' or
'obsolete'. 'obsolete'.
The module or submodule name MUST NOT be changed, once the document The module or submodule name MUST NOT be changed, once the document
containing the module or submodule is published. containing the module or submodule is published.
The module namespace URI value MUST NOT be changed, once the document The module namespace URI value MUST NOT be changed, once the document
containing the module is published. containing the module is published.
The revision-date sub-statement within the imports statement SHOULD The revision-date substatement within the imports statement SHOULD be
be present if any groupings are used from the external module. present if any groupings are used from the external module.
The revision-date sub-statement within the include statement SHOULD The revision-date substatement within the include statement SHOULD be
be present if any groupings are used from the external sub-module. present if any groupings are used from the external submodule.
If submodules are used, then the document containing the main module If submodules are used, then the document containing the main module
MUST be updated so that the main module revision date is equal or MUST be updated so that the main module revision date is equal or
more recent than the revision date of any submodule which is more recent than the revision date of any submodule that is (directly
(directly or indirectly) included by the main module. or indirectly) included by the main module.
4.7. Module Header, Meta, and Revision Statements 4.7. Module Header, Meta, and Revision Statements
For published modules, the namespace MUST be a globally unique URI, For published modules, the namespace MUST be a globally unique URI,
as defined in [RFC3986]. This value is usually assigned by the IANA. as defined in [RFC3986]. This value is usually assigned by the IANA.
The organization statement MUST be present. If the module is The organization statement MUST be present. If the module is
contained in a document intended for standards-track status, then the contained in a document intended for Standards Track status, then the
organization SHOULD be the IETF working group chartered to write the organization SHOULD be the IETF working group chartered to write the
document. document.
The contact statement MUST be present. If the module is contained in The contact statement MUST be present. If the module is contained in
a document intended for standards-track status, then the working a document intended for Standards Track status, then the working
group WEB and mailing information MUST be present, and the main group web and mailing information MUST be present, and the main
document author or editor contact information SHOULD be present. If document author or editor contact information SHOULD be present. If
additional authors or editors exist, their contact information MAY be additional authors or editors exist, their contact information MAY be
present. In addition, the Area Director and other contact present. In addition, the Area Director and other contact
information MAY be present. information MAY be present.
The description statement MUST be present. The appropriate IETF The description statement MUST be present. The appropriate IETF
Trust Copyright text MUST be present, as described in Section 3.1. Trust Copyright text MUST be present, as described in Section 3.1.
If the module relies on information contained in other documents, If the module relies on information contained in other documents,
which are not the same documents implied by the import statements which are not the same documents implied by the import statements
present in the module, then these documents MUST be identified in the present in the module, then these documents MUST be identified in the
reference statement. reference statement.
A revision statement MUST be present for each published version of A revision statement MUST be present for each published version of
the module. The revision statement MUST have a reference the module. The revision statement MUST have a reference
substatement. It MUST identify the published document which contains substatement. It MUST identify the published document that contains
the module. Modules are often extracted from their original the module. Modules are often extracted from their original
documents and it is useful for developers and operators to know how documents, and it is useful for developers and operators to know how
to find the original source document in a consistent manner. The to find the original source document in a consistent manner. The
revision statement MAY have a description substatement. revision statement MAY have a description substatement.
Each new revision MUST include a revision date which is higher than Each new revision MUST include a revision date that is higher than
any other revision date in the module. The revision date does not any other revision date in the module. The revision date does not
need to be updated if the module contents do not change in the new need to be updated if the module contents do not change in the new
document revision. document revision.
It is acceptable to reuse the same revision statement within It is acceptable to reuse the same revision statement within
unpublished versions (i.e., Internet-Drafts), but the revision date unpublished versions (i.e., Internet-Drafts), but the revision date
MUST be updated to a higher value each time the Internet-Draft is re- MUST be updated to a higher value each time the Internet-Draft is re-
published. posted.
4.8. Namespace Assignments 4.8. Namespace Assignments
It is RECOMMENDED that only valid YANG modules are included in It is RECOMMENDED that only valid YANG modules be included in
documents, whether they are published yet or not. This allows: documents, whether or not they are published yet. This allows:
o the module to compile correctly instead of generating disruptive o the module to compile correctly instead of generating disruptive
fatal errors. fatal errors.
o early implementors to use the modules without picking a random o early implementors to use the modules without picking a random
value for the XML namespace. value for the XML namespace.
o early interoperability testing since independent implementations o early interoperability testing since independent implementations
will use the same XML namespace value. will use the same XML namespace value.
Until a URI is assigned by the IANA, a proposed namespace URI MUST be Until a URI is assigned by the IANA, a proposed namespace URI MUST be
provided for the namespace statement in a YANG module. A value provided for the namespace statement in a YANG module. A value
SHOULD be selected which is not likely to collide with other YANG SHOULD be selected that is not likely to collide with other YANG
namespaces. Standard module names, prefixes, and URI strings already namespaces. Standard module names, prefixes, and URI strings already
listed in the YANG Module Registry MUST NOT be used. listed in the YANG Module Registry MUST NOT be used.
A standard namespace statement value SHOULD have the following form: A standard namespace statement value SHOULD have the following form:
<URN prefix string>:<module-name> <URN prefix string>:<module-name>
The following URN prefix string SHOULD be used for published and The following URN prefix string SHOULD be used for published and
unpublished YANG modules: unpublished YANG modules:
urn:ietf:params:xml:ns:yang: urn:ietf:params:xml:ns:yang:
The following example URNs would be valid temporary namespace The following example URNs would be valid temporary namespace
statement values for standards-track modules: statement values for Standards Track modules:
urn:ietf:params:xml:ns:yang:ietf-netconf-partial-lock urn:ietf:params:xml:ns:yang:ietf-netconf-partial-lock
urn:ietf:params:xml:ns:yang:ietf-netconf-state urn:ietf:params:xml:ns:yang:ietf-netconf-state
urn:ietf:params:xml:ns:yang:ietf-netconf urn:ietf:params:xml:ns:yang:ietf-netconf
Note that a different URN prefix string SHOULD be used for non- Note that a different URN prefix string SHOULD be used for non-
standards track modules. The string SHOULD be selected according to Standards-Track modules. The string SHOULD be selected according to
the guidelines in [I-D.ietf-netmod-yang]. the guidelines in [RFC6020].
The following examples of non-standards track modules are only The following examples of non-Standards-Track modules are only
suggestions. There are no guidelines for this type of URN in this suggestions. There are no guidelines for this type of URN in this
document: document:
http://example.com/ns/example-interfaces http://example.com/ns/example-interfaces
http://example.com/ns/example-system http://example.com/ns/example-system
4.9. Top Level Data Definitions 4.9. Top-Level Data Definitions
There SHOULD only be one top-level data node defined in each YANG There SHOULD only be one top-level data node defined in each YANG
module, if any data nodes are defined at all. module, if any data nodes are defined at all.
The top-level data organization SHOULD be considered carefully, in The top-level data organization SHOULD be considered carefully, in
advance. Data model designers need to consider how the functionality advance. Data model designers need to consider how the functionality
for a given protocol or protocol family will grow over time. for a given protocol or protocol family will grow over time.
The names and data organization SHOULD reflect persistent The names and data organization SHOULD reflect persistent
information, such as the name of a protocol. The name of the working information, such as the name of a protocol. The name of the working
group SHOULD NOT be used because this may change over time. group SHOULD NOT be used because this may change over time.
A mandatory database data definition is defined as a node that a A mandatory database data definition is defined as a node that a
client must provide for the database to be valid. The server is not client must provide for the database to be valid. The server is not
required to provide a value. required to provide a value.
Top-level database data definitions MUST NOT be mandatory. If a Top-level database data definitions MUST NOT be mandatory. If a
mandatory node appears at the top-level, it will immediately cause mandatory node appears at the top level, it will immediately cause
the database to be invalid. This can occur when the server boots or the database to be invalid. This can occur when the server boots or
when a module is loaded dynamically at runtime. when a module is loaded dynamically at runtime.
4.10. Data Types 4.10. Data Types
Selection of an appropriate data type (i.e., built-in type, existing Selection of an appropriate data type (i.e., built-in type, existing
derived type, or new derived type) is very subjective and therefore derived type, or new derived type) is very subjective, and therefore
few requirements can be specified on that subject. few requirements can be specified on that subject.
Data model designers SHOULD use the most appropriate built-in data Data model designers SHOULD use the most appropriate built-in data
type for the particular application. type for the particular application.
If extensibility of enumerated values is required, then the If extensibility of enumerated values is required, then the
'identityref' data type SHOULD be used instead of an enumeration or 'identityref' data type SHOULD be used instead of an enumeration or
other built-in type. other built-in type.
For string data types, if a machine-readable pattern can be defined For string data types, if a machine-readable pattern can be defined
skipping to change at page 17, line 30 skipping to change at page 15, line 20
'int64') SHOULD NOT be used unless negative values are allowed for 'int64') SHOULD NOT be used unless negative values are allowed for
the desired semantics. the desired semantics.
For 'enumeration' or 'bits' data types, the semantics for each 'enum' For 'enumeration' or 'bits' data types, the semantics for each 'enum'
or 'bit' SHOULD be documented. A separate description statement or 'bit' SHOULD be documented. A separate description statement
(within each 'enum' or 'bit' statement) SHOULD be present. (within each 'enum' or 'bit' statement) SHOULD be present.
4.11. Reusable Type Definitions 4.11. Reusable Type Definitions
If an appropriate derived type exists in any standard module, such as If an appropriate derived type exists in any standard module, such as
[I-D.ietf-netmod-yang-types], then it SHOULD be used instead of [RFC6021], then it SHOULD be used instead of defining a new derived
defining a new derived type. type.
If an appropriate units identifier can be associated with the desired If an appropriate units identifier can be associated with the desired
semantics, then a units statement SHOULD be present. semantics, then a units statement SHOULD be present.
If an appropriate default value can be associated with the desired If an appropriate default value can be associated with the desired
semantics, then a default statement SHOULD be present. semantics, then a default statement SHOULD be present.
If a significant number of derived types are defined, and it is If a significant number of derived types are defined, and it is
anticipated that these data types will be reused by multiple modules, anticipated that these data types will be reused by multiple modules,
then these derived types SHOULD be contained in a separate module or then these derived types SHOULD be contained in a separate module or
skipping to change at page 18, line 44 skipping to change at page 16, line 30
o rpc o rpc
o typedef o typedef
If the data definition semantics are defined in an external document, If the data definition semantics are defined in an external document,
(other than another YANG module indicated by an import statement), (other than another YANG module indicated by an import statement),
then a reference statement MUST be present. then a reference statement MUST be present.
The 'anyxml' construct may be useful to represent an HTML banner The 'anyxml' construct may be useful to represent an HTML banner
containing markup elements, such as '<b>' and '</b>', and MAY be used containing markup elements, such as '<b>' and '</b>', and MAY be used
in such cases . However, this construct SHOULD NOT be used if other in such cases. However, this construct SHOULD NOT be used if other
YANG data node types can be used instead to represent the desired YANG data node types can be used instead to represent the desired
syntax and semantics. syntax and semantics.
If there are referential integrity constraints associated with the If there are referential integrity constraints associated with the
desired semantics that can be represented with XPath, then one or desired semantics that can be represented with XPath, then one or
more must statements SHOULD be present. more 'must' statements SHOULD be present.
For list and leaf-list data definitions, if the number of possible For list and leaf-list data definitions, if the number of possible
instances is required to be bounded for all implementations, then the instances is required to be bounded for all implementations, then the
max-elements statements SHOULD be present. max-elements statements SHOULD be present.
If any must or when statements are used within the data definition, If any 'must' or 'when' statements are used within the data
then the data definition description statement SHOULD describe the definition, then the data definition description statement SHOULD
purpose of each one. describe the purpose of each one.
4.13. Operation Definitions 4.13. Operation Definitions
If the operation semantics are defined in an external document (other If the operation semantics are defined in an external document (other
than another YANG module indicated by an import statement), then a than another YANG module indicated by an import statement), then a
reference statement MUST be present. reference statement MUST be present.
If the operation impacts system behavior in some way, it SHOULD be If the operation impacts system behavior in some way, it SHOULD be
mentioned in the description statement. mentioned in the description statement.
skipping to change at page 20, line 8 skipping to change at page 17, line 29
The description statement MUST be present. The description statement MUST be present.
If the notification semantics are defined in an external document If the notification semantics are defined in an external document
(other than another YANG module indicated by an import statement), (other than another YANG module indicated by an import statement),
then a reference statement MUST be present. then a reference statement MUST be present.
5. IANA Considerations 5. IANA Considerations
This document registers one URI in the IETF XML registry [RFC3688]. This document registers one URI in the IETF XML registry [RFC3688].
The following registration is requested: The following registration has been made:
URI: urn:ietf:params:xml:ns:yang:ietf-template URI: urn:ietf:params:xml:ns:yang:ietf-template
Registrant Contact: The NETMOD WG of the IETF. Registrant Contact: The NETMOD WG of the IETF.
XML: N/A, the requested URI is an XML namespace. XML: N/A, the requested URI is an XML namespace.
This document requests the following assignment in the YANG Module Per this document, the following assignment has been made in the YANG
Names Registry for the YANG module template in Appendix B. Module Names Registry for the YANG module template in Appendix B.
+---------------+-------------------------------------------+ +---------------+-------------------------------------------+
| Field | Value | | Field | Value |
+---------------+-------------------------------------------+ +---------------+-------------------------------------------+
| name | ietf-template | | Name | ietf-template |
| | | | | |
| namespace | urn:ietf:params:xml:ns:yang:ietf-template | | Namespace | urn:ietf:params:xml:ns:yang:ietf-template |
| | | | | |
| prefix | temp | | Prefix | temp |
| | | | | |
| reference | RFCXXXX | | Reference | RFC 6087 |
+---------------+-------------------------------------------+ +---------------+-------------------------------------------+
6. Security Considerations 6. Security Considerations
This document defines documentation guidelines for NETCONF content This document defines documentation guidelines for NETCONF content
defined with the YANG data modeling language. The guidelines for how defined with the YANG data modeling language. The guidelines for how
to write a Security Considerations section for a YANG module are to write a Security Considerations section for a YANG module are
defined in the online document defined in the online document
http://www.ops.ietf.org/netconf/yang-security-considerations.txt http://www.ops.ietf.org/netconf/yang-security-considerations.txt
This document does not introduce any new or increased security risks This document does not introduce any new or increased security risks
into the management system. into the management system.
The following section contains the security considerations template The following section contains the security considerations template
dated 2010-06-16. Be sure to check the WEB page at the URL listed dated 2010-06-16. Be sure to check the webpage at the URL listed
above in case there is a more recent version available. above in case there is a more recent version available.
Each specification that defines one or more YANG modules MUST contain Each specification that defines one or more YANG modules MUST contain
a section that discusses security considerations relevant to those a section that discusses security considerations relevant to those
modules. This section MUST be patterned after the latest approved modules. This section MUST be patterned after the latest approved
template (available at [ed: URL TBD]). template (available at
http://www.ops.ietf.org/netconf/yang-security-considerations.txt).
In particular, writable data nodes that could be especially In particular, writable data nodes that could be especially
disruptive if abused MUST be explicitly listed by name and the disruptive if abused MUST be explicitly listed by name and the
associated security risks MUST be spelled out. associated security risks MUST be spelled out.
Similarly, readable data nodes that contain especially sensitive Similarly, readable data nodes that contain especially sensitive
information or that raise significant privacy concerns MUST be information or that raise significant privacy concerns MUST be
explicitly listed by name and the reasons for the sensitivity/privacy explicitly listed by name and the reasons for the sensitivity/privacy
concerns MUST be explained. concerns MUST be explained.
Further, if new RPC operations have been defined, then the security Further, if new RPC operations have been defined, then the security
considerations of each new RPC operation MUST be explained. considerations of each new RPC operation MUST be explained.
6.1. Security Considerations Section Template 6.1. Security Considerations Section Template
X. Security Considerations
X. Security Considerations
The YANG module defined in this memo is designed to be accessed The YANG module defined in this memo is designed to be accessed
via the NETCONF protocol [RFC4741]. The lowest NETCONF layer is via the NETCONF protocol [RFC4741]. The lowest NETCONF layer is
the secure transport layer and the mandatory to implement secure the secure transport layer and the mandatory-to-implement secure
transport is SSH [RFC4742]. transport is SSH [RFC4742].
-- if you have any writeable data nodes (those are all the -- if you have any writable data nodes (those are all the
-- "config true" nodes, and remember, that is the default) -- "config true" nodes, and remember, that is the default)
-- describe their specific sensitivity or vulnerability. -- describe their specific sensitivity or vulnerability.
There are a number of data nodes defined in this YANG module There are a number of data nodes defined in this YANG module
which are writable/creatable/deletable (i.e. config true, which which are writable/creatable/deletable (i.e., config true, which
is the default). These data nodes may be considered sensitive is the default). These data nodes may be considered sensitive
or vulnerable in some network environments. Write operations or vulnerable in some network environments. Write operations
(e.g. edit-config) to these data nodes without proper protection (e.g., edit-config) to these data nodes without proper protection
can have a negative effect on network operations. These are can have a negative effect on network operations. These are
the subtrees and data nodes and their sensitivity/vulnerability: the subtrees and data nodes and their sensitivity/vulnerability:
<list subtrees and data nodes and state why they are sensitive> <list subtrees and data nodes and state why they are sensitive>
-- for all YANG modules you must evaluate whether any readable data -- for all YANG modules you must evaluate whether any readable data
-- nodes (those are all the "config false" nodes, but also all other -- nodes (those are all the "config false" nodes, but also all other
-- nodes, because they can also be read via operations like get or -- nodes, because they can also be read via operations like get or
-- get-config) are sensitive or vulnerable (for instance, if they -- get-config) are sensitive or vulnerable (for instance, if they
-- might reveal customer information or violate personal privacy -- might reveal customer information or violate personal privacy
-- laws such as those of the European Union if exposed to -- laws such as those of the European Union if exposed to
-- unauthorized parties) -- unauthorized parties)
Some of the readable data nodes in this YANG module may be Some of the readable data nodes in this YANG module may be
considered sensitive or vulnerable in some network environments. considered sensitive or vulnerable in some network environments.
It is thus important to control read access (e.g. via get, It is thus important to control read access (e.g., via get,
get-config or notification) to these data nodes. These are the get-config, or notification) to these data nodes. These are the
subtrees and data nodes and their sensitivity/vulnerability: subtrees and data nodes and their sensitivity/vulnerability:
<list subtrees and data nodes and state why they are sensitive> <list subtrees and data nodes and state why they are sensitive>
-- if your YANG module has defined any rpc operations -- if your YANG module has defined any rpc operations
-- describe their specific sensitivity or vulnerability. -- describe their specific sensitivity or vulnerability.
Some of the RPC operations in this YANG module may be considered Some of the RPC operations in this YANG module may be considered
sensitive or vulnerable in some network environments. It is thus sensitive or vulnerable in some network environments. It is thus
important to control access to these operations. These are the important to control access to these operations. These are the
operations and their sensitivity/vulnerability: operations and their sensitivity/vulnerability:
<list RPC operations and state why they are sensitive> <list RPC operations and state why they are sensitive>
Figure 2
7. Acknowledgments 7. Acknowledgments
The structure and contents of this document are adapted from The structure and contents of this document are adapted from
Guidelines for MIB Documents [RFC4181], by C. M. Heard. Guidelines for MIB Documents [RFC4181], by C. M. Heard.
The working group thanks Martin Bjorklund and Juergen Schoenwaelder The working group thanks Martin Bjorklund and Juergen Schoenwaelder
for their extensive reviews and contributions to this document. for their extensive reviews and contributions to this document.
8. References 8. References
skipping to change at page 25, line 37 skipping to change at page 20, line 45
[RFC5741] Daigle, L., Kolkman, O., and IAB, "RFC Streams, Headers, [RFC5741] Daigle, L., Kolkman, O., and IAB, "RFC Streams, Headers,
and Boilerplates", RFC 5741, December 2009. and Boilerplates", RFC 5741, December 2009.
[W3C.REC-xpath-19991116] [W3C.REC-xpath-19991116]
DeRose, S. and J. Clark, "XML Path Language (XPath) DeRose, S. and J. Clark, "XML Path Language (XPath)
Version 1.0", World Wide Web Consortium Version 1.0", World Wide Web Consortium
Recommendation REC-xpath-19991116, November 1999, Recommendation REC-xpath-19991116, November 1999,
<http://www.w3.org/TR/1999/REC-xpath-19991116>. <http://www.w3.org/TR/1999/REC-xpath-19991116>.
[I-D.ietf-netmod-yang] [RFC6020] Bjorklund, M., "YANG - A Data Modeling Language for the
Bjorklund, M., "YANG - A data modeling language for the Network Configuration Protocol (NETCONF)", RFC 6020,
Network Configuration Protocol (NETCONF)", October 2010.
draft-ietf-netmod-yang-13 (work in progress), June 2010.
[I-D.ietf-netmod-yang-types] [RFC6021] Schoenwaelder, J., "Common YANG Data Types", RFC 6021,
Schoenwaelder, J., "Common YANG Data Types", October 2010.
draft-ietf-netmod-yang-types-09 (work in progress),
April 2010.
8.2. Informative References 8.2. Informative References
[RFC4181] Heard, C., "Guidelines for Authors and Reviewers of MIB [RFC4181] Heard, C., "Guidelines for Authors and Reviewers of MIB
Documents", BCP 111, RFC 4181, September 2005. Documents", BCP 111, RFC 4181, September 2005.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226, IANA Considerations Section in RFCs", BCP 26, RFC 5226,
May 2008. May 2008.
[RFC-STYLE]
Braden, R., Ginoza, S., and A. Hagens, "RFC Document
Style", September 2009,
<http://www.rfc-editor.org/rfc-style-guide/rfc-style>.
Appendix A. Module Review Checklist Appendix A. Module Review Checklist
This section is adapted from RFC 4181. This section is adapted from RFC 4181.
The purpose of a YANG module review is to review the YANG module both The purpose of a YANG module review is to review the YANG module both
for technical correctness and for adherence to IETF documentation for technical correctness and for adherence to IETF documentation
requirements. The following checklist may be helpful when reviewing requirements. The following checklist may be helpful when reviewing
a draft document: an Internet-Draft:
1. I-D Boilerplate -- verify that the draft contains the required 1. I-D Boilerplate -- verify that the draft contains the required
Internet-Draft boilerplate (see Internet-Draft boilerplate (see
http://www.ietf.org/ietf/1id-guidelines.txt), including the http://www.ietf.org/id-info/guidelines.html), including the
appropriate statement to permit publication as an RFC, and that appropriate statement to permit publication as an RFC, and that
I-D boilerplate does not contain references or section numbers. I-D boilerplate does not contain references or section numbers.
2. Abstract -- verify that the abstract does not contain references, 2. Abstract -- verify that the abstract does not contain references,
that it does not have a section number, and that its content that it does not have a section number, and that its content
follows the guidelines in follows the guidelines in
http://www.ietf.org/ietf/1id-guidelines.txt. http://www.ietf.org/id-info/guidelines.html.
3. IETF Trust Copyright -- verify that the draft has the appropriate 3. Copyright Notice -- verify that the draft has the appropriate
text regarding the rights that document contributers provide to text regarding the rights that document contributers provide to
the IETF Trust [RFC5378]. Some guidelines related to this the IETF Trust [RFC5378]. Verify that it contains the full IETF
requirement are described in Section 3.1. The IETF Trust license Trust copyright notice at the beginning of the document. The
policy (TLP) can be found at: IETF Trust Legal Provisions (TLP) can be found at:
http://trustee.ietf.org/docs/IETF-Trust-License-Policy.pdf http://trustee.ietf.org/license-info/
4. Security Considerations Section -- verify that the draft uses the 4. Security Considerations section -- verify that the draft uses the
latest approved template from the OPS area web site (http:// latest approved template from the OPS area website (http://
www.ops.ietf.org/netconf/yang-security-considerations.txt) and www.ops.ietf.org/netconf/yang-security-considerations.txt) and
that the guidelines therein have been followed. that the guidelines therein have been followed.
5. IANA Considerations Section -- this section must always be 5. IANA Considerations section -- this section must always be
present. For each module within the document, ensure that the present. For each module within the document, ensure that the
IANA Considerations section contains entries for the following IANA Considerations section contains entries for the following
IANA registries: IANA registries:
XML Namespace Registry: Register the YANG module namespace. XML Namespace Registry: Register the YANG module namespace.
YANG Module Registry: Register the YANG module name, prefix, YANG Module Registry: Register the YANG module name, prefix,
namespace, and RFC number, according to the rules specified in namespace, and RFC number, according to the rules specified in
[I-D.ietf-netmod-yang]. [RFC6020].
6. References -- verify that the references are properly divided 6. References -- verify that the references are properly divided
between normative and informative references, that RFC 2119 is between normative and informative references, that RFC 2119 is
included as a normative reference if the terminology defined included as a normative reference if the terminology defined
therein is used in the document, that all references required by therein is used in the document, that all references required by
the boilerplate are present, that all YANG modules containing the boilerplate are present, that all YANG modules containing
imported items are cited as normative references, and that all imported items are cited as normative references, and that all
citations point to the most current RFCs unless there is a valid citations point to the most current RFCs unless there is a valid
reason to do otherwise (for example, it is OK to include an reason to do otherwise (for example, it is OK to include an
informative reference to a previous version of a specification to informative reference to a previous version of a specification to
help explain a feature included for backward compatibility). Be help explain a feature included for backward compatibility). Be
sure citations for all imported modules are present somewhere in sure citations for all imported modules are present somewhere in
the document text (outside the YANG module). the document text (outside the YANG module).
7. Copyright Notices -- verify that the draft contains an 7. License -- verify that the draft contains the Simplified BSD
abbreviated IETF Trust copyright notice in the description License in each YANG module or submodule. Some guidelines
statement of each YANG module or sub-module, and that it contains related to this requirement are described in Section 3.1. Make
the full IETF Trust copyright notice at the end of the document. sure that the correct year is used in all copyright dates. Use
Make sure that the correct year is used in all copyright dates. the approved text from the latest Trust Legal Provisions (TLP)
Use the approved text from the latest Trust Legal Provisions document, which can be found at:
(TLP) document, which can be found at:
http://trustee.ietf.org/license-info/ http://trustee.ietf.org/license-info/
8. Other Issues -- check for any issues mentioned in 8. Other Issues -- check for any issues mentioned in
http://www.ietf.org/ID-Checklist.html that are not covered http://www.ietf.org/id-info/checklist.html that are not covered
elsewhere. elsewhere.
9. Technical Content -- review the actual technical content for 9. Technical Content -- review the actual technical content for
compliance with the guidelines in this document. The use of a compliance with the guidelines in this document. The use of a
YANG module compiler is recommended when checking for syntax YANG module compiler is recommended when checking for syntax
errors. A list of freely available tools and other information errors. A list of freely available tools and other information
can be found at: can be found at:
http://trac.tools.ietf.org/wg/netconf/trac/wiki http://trac.tools.ietf.org/wg/netconf/trac/wiki
skipping to change at page 29, line 32 skipping to change at page 24, line 32
// identify the IETF working group if applicable // identify the IETF working group if applicable
organization organization
"IETF NETMOD (NETCONF Data Modeling Language) Working Group"; "IETF NETMOD (NETCONF Data Modeling Language) Working Group";
// update this contact statement with your info // update this contact statement with your info
contact contact
"WG Web: <http://tools.ietf.org/wg/your-wg-name/> "WG Web: <http://tools.ietf.org/wg/your-wg-name/>
WG List: <mailto:your-wg-name@ietf.org> WG List: <mailto:your-wg-name@ietf.org>
WG Chair: your-WG-chair WG Chair: your-WG-chair
<mailto:your-WG-chair@example.com> <mailto:your-WG-chair@example.com>
Editor: your-name Editor: your-name
<mailto:your-email@example.com>"; <mailto:your-email@example.com>";
// replace the first sentence in this description statement. // replace the first sentence in this description statement.
// replace the copyright notice with the most recent // replace the copyright notice with the most recent
// version, if it has been updated since the publication // version, if it has been updated since the publication
// of this document // of this document
description description
"This module defines a template for other YANG modules. "This module defines a template for other YANG modules.
Copyright (c) 2010 IETF Trust and the persons identified as Copyright (c) <insert year> IETF Trust and the persons
the document authors. All rights reserved. identified as authors of the code. All rights reserved.
Redistribution and use in source and binary forms, with or Redistribution and use in source and binary forms, with or
without modification, is permitted pursuant to, and subject without modification, is permitted pursuant to, and subject
to the license terms contained in, the Simplified BSD License to the license terms contained in, the Simplified BSD License
set forth in Section 4.c of the IETF Trust's Legal Provisions set forth in Section 4.c of the IETF Trust's Legal Provisions
Relating to IETF Documents Relating to IETF Documents
(http://trustee.ietf.org/license-info). (http://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC XXXX; see This version of this YANG module is part of RFC XXXX; see
the RFC itself for full legal notices."; the RFC itself for full legal notices.";
// RFC Ed.: replace XXXX with actual RFC number and remove this note // RFC Ed.: replace XXXX with actual RFC number and remove this note
reference "RFC XXXX"; reference "RFC XXXX";
// RFC Ed.: remove this note // RFC Ed.: remove this note
// Note: extracted from draft-ietf-netmod-yang-usage-04.txt // Note: extracted from RFC 6087
// replace '2010-05-18' with the module publication date // replace '2010-05-18' with the module publication date
// The format is (year-month-day) // The format is (year-month-day)
revision "2010-05-18" { revision "2010-05-18" {
description description
"Initial version"; "Initial version";
} }
// extension statements // extension statements
skipping to change at page 31, line 4 skipping to change at page 26, line 4
// rpc statements // rpc statements
// notification statements // notification statements
// DO NOT put deviation statements in a published module // DO NOT put deviation statements in a published module
} }
<CODE ENDS> <CODE ENDS>
Figure 3
Appendix C. Change Log
C.1. Changes from 10 to 11
o Removed Intellectual Property section, since no longer required.
o Reworded XPath guidelines related to XML document order, 'int64'
and 'uint64' data types, and 'anyxml' data nodes.
C.2. Changes from 09 to 10
o Added security considerations section template.
o Added guideline for documenting conditional requirements for non-
mandatory non-configuration data nodes.
o Clarified that revision date update applies to the module
contents.
C.3. Changes from 08 to 09
o Clarifications and corrections to address Gen-ART review comments.
C.4. Changes from 07 to 08
o Corrected YANG security considerations URL.
o Expanded 'CODE BEGINS' example.
o Added RPC operations to the security considerations guidelines
section.
o Removed guideline about leading and trailing whitespace.
C.5. Changes from 06 to 07
o Corrected title change bug; supposed to be page header instead.
o Fixed typos added to last revision.
o Added sentence to checklist to make sure text outside module
contains citations for imports.
C.6. Changes from 05 to 06
o Several clarifications and corrections, based on the AD review by
Dan Romascanu.
C.7. Changes from 04 to 05
o Changed 'object' terminology to 'data definition'.
o Put XPath guidelines in separate section.
o Clarified XPath usage for XML document order dependencies.
o Updated <CODE BEGINS> guidelines to current conventions.
o Added informative reference for IANA considerations guidelines and
XML registry.
o Updated IANA Considerations section to reserve the ietf-template
module in the YANG Module Name Registry so it cannot be reused
accidently.
o Many other clarifications and fixed typos found in WGLC reviews.
C.8. Changes from 03 to 04
o Removed figure 1 to reduce duplication, just refer to 4741bis
draft.
o Fixed bugs and typos found in WGLC reviews.
o Removed some guidelines and referring to YANG draft instead of
duplicating YANG rules here.
o Changed security guidelines so they refer to the IETF Trust TLP
instead of MIB-specific references.
o Change temporary namespace guidelines so the DRAFT-XX and RFC-nnnn
suffix strings are not used.
o Changed some MIB boilerplate so it refers to YANG boilerplate
instead.
o Introduced dangling URL reference to online YANG security
guidelines
http://www.ops.ietf.org/yang-security.html
[ed.: Text from Bert Wijnen will be completed soon and posted
online, and then this URL will be finalized.]
o Moved reference for identifying the source document inside the
each revision statement.
o Removed guideline about valid XPath since YANG already requires
valid XPath.
o Added guideline that strings should not rely on preservation of
leading and trailing whitespace characters.
o Relaxed some XPath and anyxml guidelines from SHOULD NOT or MUST
NOT to MAY use with caution.
o Updated the TLP text within the example module again.
o Reversed order of change log so most recent entries are first.
C.9. Changes from 02 to 03
o Updated figure 1 to align with 4741bis draft.
o Updated guidelines for import-by-revision and include-by-revision.
o Added file name to code begins convention in ietf-template module.
C.10. Changes from 01 to 02
o Updated figure 1 per mailing list comments.
o Updated suggested organization to include the working group name.
o Updated ietf-template.yang to use new organization statement
value.
o Updated Code Component requirements as per new TLP.
o Updated ietf-template.yang to use new Code Component begin and end
markers.
o Updated references to the TLP in a couple sections.
o Change manager/agent terminology to client/server.
C.11. Changes from 00 to 01
o Added transport 'TLS' to figure 1.
o Added note about RFC 2119 terminology.
o Corrected URL for instructions to authors.
o Updated namespace procedures section.
o Updated guidelines on module contact, reference, and organization
statements.
o Added note on use of preceding-sibling and following-sibling axes
in XPath expressions.
o Added section on temporary namespace statement values.
o Added section on top level database objects.
o Added ietf-template.yang appendix.
Author's Address Author's Address
Andy Bierman Andy Bierman
Brocade Brocade
Email: andy.bierman@brocade.com EMail: andy.bierman@brocade.com
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