Internet Engineering Task Force A. Bierman
Internet-Draft Netconf Central, Inc.
Intended status: Informational October 26, 2009
Expires: April 29, 2010
Guidelines for Authors and Reviewers of YANG Data Model Documents
draft-ietf-netmod-yang-usage-02
Status of this Memo
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provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on April 29, 2010.
Copyright Notice
Copyright (c) 2009 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 in effect on the date of
publication of this document (http://trustee.ietf.org/license-info).
Please review these documents carefully, as they describe your rights
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Abstract
This memo provides guidelines for authors and reviewers of standards
track specifications containing YANG data model modules. Applicable
portions may be used as a basis for reviews of other YANG data model
documents. Recommendations and procedures are defined, which are
intended to increase interoperability and usability of NETCONF
implementations which utilize YANG data model modules.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1. Requirements Notation . . . . . . . . . . . . . . . . . . 5
2.2. NETCONF Terms . . . . . . . . . . . . . . . . . . . . . . 5
2.3. YANG Terms . . . . . . . . . . . . . . . . . . . . . . . . 5
2.4. Terms . . . . . . . . . . . . . . . . . . . . . . . . . . 6
3. General Documentation Guidelines . . . . . . . . . . . . . . . 7
3.1. YANG Data Model Boilerplate Section . . . . . . . . . . . 7
3.2. Narrative Sections . . . . . . . . . . . . . . . . . . . . 7
3.3. Definitions Section . . . . . . . . . . . . . . . . . . . 8
3.4. Security Considerations Section . . . . . . . . . . . . . 8
3.5. IANA Considerations Section . . . . . . . . . . . . . . . 8
3.5.1. Documents that Create a New Name Space . . . . . . . . 8
3.5.2. Documents that Extend an Existing Name Space . . . . . 9
3.6. Reference Sections . . . . . . . . . . . . . . . . . . . . 9
3.7. Copyright Notices . . . . . . . . . . . . . . . . . . . . 9
3.8. Intellectual Property Section . . . . . . . . . . . . . . 9
4. YANG Usage Guidelines . . . . . . . . . . . . . . . . . . . . 10
4.1. Module Naming Conventions . . . . . . . . . . . . . . . . 10
4.2. Identifiers . . . . . . . . . . . . . . . . . . . . . . . 10
4.3. Defaults . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.4. Conditional Statements . . . . . . . . . . . . . . . . . . 11
4.5. Lifecycle Management . . . . . . . . . . . . . . . . . . . 12
4.6. Header Contents . . . . . . . . . . . . . . . . . . . . . 12
4.7. Temporary Namespace Assignments . . . . . . . . . . . . . 13
4.8. Top Level Database Objects . . . . . . . . . . . . . . . . 14
4.9. Data Types . . . . . . . . . . . . . . . . . . . . . . . . 15
4.10. Reusable Type Definitions . . . . . . . . . . . . . . . . 15
4.11. Object Definitions . . . . . . . . . . . . . . . . . . . . 16
4.12. RPC Definitions . . . . . . . . . . . . . . . . . . . . . 17
4.13. Notification Definitions . . . . . . . . . . . . . . . . . 17
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18
6. Security Considerations . . . . . . . . . . . . . . . . . . . 19
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 20
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 21
8.1. Normative References . . . . . . . . . . . . . . . . . . . 21
8.2. Informative References . . . . . . . . . . . . . . . . . . 21
Appendix A. Module Review Checklist . . . . . . . . . . . . . . . 22
Appendix B. YANG Module Template . . . . . . . . . . . . . . . . 24
Appendix C. Change Log . . . . . . . . . . . . . . . . . . . . . 27
C.1. Changes from 00 to 01 . . . . . . . . . . . . . . . . . . 27
C.2. Changes from 01 to 02 . . . . . . . . . . . . . . . . . . 27
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 28
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1. Introduction
The standardization of network configuration interfaces for use with
the NETCONF [RFC4741] protocol requires a modular set of data models,
which can be reused and extended over time.
This document defines a set of usage guidelines for standards track
documents containing YANG [I-D.ietf-netmod-yang] data models. It is
similar to the MIB usage guidelines specification [RFC4181] in intent
and structure.
Many YANG constructs are defined as optional to use, such as the
description clause. However, in order to maximize interoperability
of NETCONF implementations utilizing YANG data models, it is
desirable to define a set of usage guidelines which may require a
higher level of compliance than the minimum level defined in the YANG
specification.
The NETCONF stack can be conceptually partitioned into four layers.
Layer Example
+-------------+ +--------------------+ +-------------------+
(4) | Content | | Configuration data | | Notification data |
+-------------+ +--------------------+ +-------------------+
| | |
+-------------+ +-----------------+ +---------------+
(3) | Operations | | <edit-config> | | <eventType> |
+-------------+ +-----------------+ +---------------+
| | |
+-------------+ +--------------------+ +----------------+
(2) | Messages | | <rpc>, <rpc-reply> | | <notification> |
+-------------+ +--------------------+ +----------------+
| | |
+-------------+ +-----------------------------------------------+
(1) | Secure | | SSH, TLS, BEEP/TLS, SOAP/BEEP, SOAP/HTTPS ... |
| Transports | | |
+-------------+ +-----------------------------------------------+
Figure 1
This document defines usage guidelines related to the NETCONF
operations layer (3), and NETCONF content layer (4).
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2. Terminology
2.1. Requirements Notation
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
RFC 2119 language is used here to express the views of the NETMOD
working group regarding YANG module content. Yang modules complying
with this document will treat the RFC 2119 terminology as if it were
describing best current practices.
2.2. NETCONF Terms
The following terms are defined in [RFC4741] and are not redefined
here:
o application
o capabilities
o client
o operation
o RPC
o server
2.3. YANG Terms
The following terms are defined in [I-D.ietf-netmod-yang] and are not
redefined here:
o data node
o module
o submodule
o namespace
o version
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2.4. Terms
The following terms are used throughout this document:
o module: Generic term for a YANG data model module or submodule.
When describing properties which are specific to submodules, the
term 'YANG submodule', or simply 'submodule' is used instead.
o Published Document: A stable release of a module, usually
contained in an RFC.
o Unpublished Document: An unstable release of a module, usually
contained in an Internet Draft.
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3. General Documentation Guidelines
YANG data model modules under review are likely to be contained in
Internet Drafts. All guidelines for Internet Draft authors MUST be
followed. These guidelines are available online at:
http://www.rfc-editor.org/rfc-editor/instructions2authors.txt
The following sections MUST be present in an Internet Draft
containing a module:
o YANG data model boilerplate section
o Narrative sections
o Definitions section
o Security Considerations section
o IANA Considerations section
o References section
3.1. YANG Data Model Boilerplate Section
This section MUST contain a verbatim copy of the latest approved
Internet-Standard Management Framework boilerplate, which is
available on-line, in section 4 of the Trust Legal Provisions (TLP)
document, at: http://trustee.ietf.org/license-info/
Each YANG module contained within an Internet Draft or RPC MUST be
identified as a 'Code Component'. The strings '<CODE BEGINS>' and
'<CODE ENDS>' SHOULD be used to identify each Code Component.
3.2. Narrative Sections
The narrative part MUST include an overview section that describes
the scope and field of application of the module(s) defined by the
specification and that specifies the relationship (if any) of these
modules to other standards, particularly to standards containing
other module modules. The narrative part SHOULD include one or more
sections to briefly describe the structure of the modules defined in
the specification.
If the module(s) defined by the specification import definitions from
other modules (except for those defined in the YANG
[I-D.ietf-netmod-yang] or YANG Types [I-D.ietf-netmod-yang-types]
documents) or are always implemented in conjunction with other
modules, then those facts MUST be noted in the overview section, as
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MUST any special interpretations of objects in other modules.
3.3. Definitions Section
This section contains the module(s) defined by the specification.
These modules MUST be written in YANG [I-D.ietf-netmod-yang].
See Section 4 for guidelines on YANG usage.
3.4. Security Considerations Section
Each specification that defines one or more modules MUST contain a
section that discusses security considerations relevant to those
modules. This section MUST be patterned after the latest approved
template (available at [ed: URL TBD]).
In particular, writable module objects that could be especially
disruptive if abused MUST be explicitly listed by name and the
associated security risks MUST be spelled out; similarly, readable
module objects that contain especially sensitive information or that
raise significant privacy concerns MUST be explicitly listed by name
and the reasons for the sensitivity/privacy concerns MUST be
explained.
3.5. IANA Considerations Section
In order to comply with IESG policy as set forth in
http://www.ietf.org/ID-Checklist.html, every Internet-Draft that is
submitted to the IESG for publication MUST contain an IANA
Considerations section. The requirements for this section vary
depending what actions are required of the IANA.
3.5.1. Documents that Create a New Name Space
If an Internet-Draft defines a new name space that is to be
administered by the IANA, then the document MUST include an IANA
Considerations section, that specifies how the name space is to be
administered.
Specifically, if any YANG module namespace statement value contained
in the document is not already registered with IANA, then a new YANG
Namespace registry entry must be requested from the IANA. The YANG
specification includes the procedure for this purpose in its IANA
Considerations section.
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3.5.2. Documents that Extend an Existing Name Space
If an Internet-Draft defines any extensions to a YANG Namespace
already administered by the IANA, then the document MUST include an
IANA Considerations section, specifies how the name space extension
is to be administered.
Specifically, if any YANG submodule belongs-to value contained in the
document is associated with a module that contains a namespace
statement value equal to a YANG Namespace already administered by the
IANA, then the existing YANG Namespace must be updated to include the
new submodule.
3.6. Reference Sections
For every import or include statement which appears in a module
contained in the specification, which identifies a module in a
separate document, a corresponding normative reference to that
document MUST appear in the Normative References section. The
reference MUST correspond to the specific module version actually
used within the specification.
For every reference statement which appears in a module contained in
the specification, which identifies a separate document, a
corresponding normative reference to that document SHOULD appear in
the Normative References section. The reference SHOULD correspond to
the specific document version actually used within the specification.
3.7. Copyright Notices
The proper copyright notices MUST be present in the module
description statement. Refer to the IETF Trust Legal Provision for
the exact legal text that needs to be included.
3.8. Intellectual Property Section
The proper IPR statements MUST be present in the document, according
to the most current Internet Draft boilerplate. Refer to the IETF
Trust Legal Provision for the exact legal text that needs to be
included.
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4. YANG Usage Guidelines
In general, modules in IETF standards-track specifications MUST
comply with all syntactic and semantic requirements of YANG.
[I-D.ietf-netmod-yang]. The guidelines in this section are intended
to supplement the YANG specification, which is intended to define a
minimum set of conformance requirements.
In order to promote interoperability and establish a set of practices
based on previous experience, the following sections establish usage
guidelines for specific YANG constructs.
Only guidelines which clarify or restrict the minimum conformance
requirements are included here.
4.1. Module Naming Conventions
Modules contained in standards track documents SHOULD be named with
the prefix 'ietf-'. Other types of modules MUST NOT use the 'ietf-'
prefix string.
A distinctive word or acronym (e.g., protocol name or working group
acronym) SHOULD be used in the module name. If new definitions are
being defined to extend one or more existing modules, then the same
word or acronym should be reused, instead of creating a new one.
All published module names MUST be unique.
Once a module name is published, it MUST not be reused, even if the
RFC containing the module is reclassified to 'Historic' status.
4.2. Identifiers
Identifiers for modules, submodules, typedefs, groupings, data
objects, rpcs, and notifications MUST be between 1 and 64 characters
in length.
4.3. Defaults
In general, it is suggested that sub-statements containing default
values SHOULD NOT be present. For example, 'status current;',
'config true;', 'mandatory false;', and 'max-elements unbounded;' are
common defaults which would make the module difficult to read if used
everywhere they are allowed.
Instead, it is suggested that common statements SHOULD only be used
when being set to a value other than the default value.
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4.4. Conditional Statements
A module may be conceptually partitioned in several ways, using the
'if-feature' and/or 'when' statements. In addition, NETCONF
capabilities are designed to identify optional functionality.
Data model designers need to carefully consider all modularity
aspects, including the use of YANG conditional statements.
Objects SHOULD NOT directly reference NETCONF capabilities, in order
to specify optional behavior. Instead, a 'feature' statement SHOULD
be defined to represent the NETCONF capability, and the 'if-feature'
statement SHOULD be used within the object definition.
If the condition associated with the desired semantics is not
dependent on any particular instance value within the database, then
an 'if-feature' statement SHOULD be used instead of a 'when'
statement.
All 'must' and 'when' statements MUST contain valid XPath. If any
name tests are present, they MUST contain valid module prefixes and
data node names. References to non-existent nodes are considered
invalid in YANG, even though they are permitted in XPath.
The 'attribute' and 'namespace' axis SHOULD NOT be used because the
associated XML node types are not supported in YANG, and may not be
supported consistently across NETCONF server implementations.
The 'position' and 'last' functions SHOULD NOT be used. Also, the
'preceding', and 'following' axes SHOULD NOT be used. These
constructs rely on XML document order within a NETCONF server
configuration database, which may not be supported consistently or
produce reliable results across implementations. Predicate
expressions based on static node properties (e.g., name, value,
ancestors, descendants) SHOULD be used instead.
The 'preceding-sibling' and 'following-sibling' axes MAY be used,
with caution. A server is not required to maintain a persistent or
deterministic XML document order, which will affect use of these
axes.
Implicit 'position' function calls within predicates SHOULD NOT be
used. (e.g., //chapter[42]).
Data nodes which use the 'int64' and 'uint64' built-in type SHOULD
NOT be used within relational expressions. There are boundary
conditions in which the translation from the YANG 64-bit type to an
XPath number can cause incorrect results.
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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 conversion between YANG and XPath data types SHOULD be considered
carefully.
Explicit XPath data type conversions MAY be used (e.g., 'string',
'boolean', or 'number' functions), instead of implicit XPath data
type conversions.
4.5. Lifecycle Management
The status statement SHOULD NOT be present if its value is 'current'.
It MUST be present if its value is 'deprecated' or 'obsolete'.
The module or submodule name MUST NOT be changed, once the document
containing the module or submodule is published.
The module namespace URI value SHOULD NOT be changed, once the
document containing the module is published.
The revision-date sub-statement (within the imports statement) SHOULD
be present. It MUST be present (in all published modules) if any
groupings are used from the external module.
The revision-date sub-statement (within the include statement) MAY be
present. It SHOULD be present (in all published modules) if any
groupings are used from the external sub-module.
4.6. Header Contents
For published modules, the namespace MUST be a globally unique URI,
as defined in [RFC3986]. This value is usually assigned by the IANA.
The organization statement MUST be present. If the module is
contained in a documented intended for standards-track status, then
the organization SHOULD be the IETF working group chartered to write
the document.
The contact statement MUST be present. If the module is contained in
a documented intended for standards-track status, then the working
group WEB and mailing information MUST be present, and the document
author contact information SHOULD be present. In addition, the Area
Director and other contact information MAY be present.
The description statement MUST be present. If the module is
contained in an unpublished document, then the file name of this
document SHOULD be identified in the description statement. This
text MUST be removed when the document is published.
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Modules are often extracted from their original documents and it is
useful for developers and operators to know how to find the original
source document in a consistent manner.
The reference statement MUST be present. It MUST identify the
published document which contains the module.
If the module relies on information contained in other documents,
which are not the same documents implied by the import statements
present in the module, then these documents MUST be identified in the
reference statement.
A revision statement MUST be present for each published version of
the module.
Each new revision MUST include a revision date which is higher than
any other revision date in the module.
It is acceptable to reuse the same revision statement within
unpublished versions (i.e., Internet Drafts), but the revision date
MUST be updated to a higher value each time the Internet Draft is re-
published.
4.7. Temporary Namespace Assignments
It is desirable to include only valid YANG modules in documents,
whether they are published yet or not.
o allows the module to compile correctly instead of generating
disruptive fatal errors.
o allows early implementors to use the modules without picking a
random value for this field.
o allows early interoperability testing since independent
implementations will use the same namespace value.
Until a URI is assigned by the IANA, a temporary namespace URI MUST
be provided for the namespace statement in a YANG module. A value
SHOULD be selected which is not likely to collide with other YANG
namespaces.
An unpublished module namespace statement value SHOULD include the
field 'DRAFT-nn', where 'nn' is replaced by the current Internet
Draft number.
If the YANG module has been previously published, then the RPC being
updated needs to be identified. In this case, an unpublished module
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namespace statement value SHOULD include the field
'DRAFT-XXXXBIS-nn', where 'XXXX' is replaced by the RFC number being
updated, and 'nn' is replaced by the current Internet Draft number.
A temporary namespace statement value SHOULD have the following form:
<URN prefix string>:<module-name>:<draft-field>
The suggested URN prefix string that SHOULD be used is shown below.
This value will be defined by the IANA. urn:ietf:params:xml:ns:yang:
The following example URNs would be valid temporary namespace
statement values:
urn:ietf:params:xml:ns:yang:ietf-netconf-partial-lock:DRAFT-09
urn:ietf:params:xml:ns:yang:ietf-netconf-state:DRAFT-07
urn:ietf:params:xml:ns:yang:ietf-netconf:DRAFT-4741BIS-01
4.8. Top Level Database Objects
There SHOULD only be one top-level data node defined in each YANG
module. However, there MAY be more than one if needed.
The top-level data organization SHOULD be considered carefully, in
advance. Data model designers need to consider how the functionality
for a given protocol or protocol family will grow over time.
The names and data organization SHOULD reflect persistent
information, such as the name of a protocol. The name of the working
group SHOULD NOT be used because this may change over time.
A mandatory database object is defined as a node that a client must
provide for the database to be valid. The server will not provide a
value under any conditions.
Top-level database objects MUST NOT be mandatory.
If a mandatory node appears at the top-level, it will immediately
cause the database to be invalid. This can occur when the server
boots or when a module is loaded dynamically at runtime.
Top level objects are declared in YANG as mandatory with the
mandatory statement or the min-elements statement. All nested non-
presence containers are transparent, so a mandatory node nested
within one or more non-presence containers causes the top-level
container to be considered mandatory.
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4.9. Data Types
Selection of an appropriate data type (i.e., built-in type, existing
derived type, or new derived type) is very subjective and therefore
few requirements can be specified on that subject.
Data model designers SHOULD use the most appropriate built-in data
type for the particular application.
If extensibility of enumerated values is required, then the
identityref data type SHOULD be used instead of an enumeration or
other built-in type.
For string data types, if a machine-readable pattern can be defined
for the desired semantics, then one or more pattern statements SHOULD
be present.
For string data types, if the length of the string is not required to
be unbounded in all implementations, then a length statement SHOULD
be present.
For numeric data types, if the values allowed by the intended
semantics are different than those allowed by the unbounded intrinsic
data type (e.g., int32), then a range statement SHOULD be present.
The signed numeric data types (i.e., 'int8', 'int16', 'int32', and
'int64') SHOULD NOT be used unless negative values are allowed for
the desired semantics.
For enumeration or bits data types, the semantics for each enum or
bit SHOULD be documented. A separate description statement (within
each enum or bit statement) SHOULD be present.
4.10. Reusable Type Definitions
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
defining a new derived type.
If an appropriate units identifier can be associated with the desired
semantics, then a units statement SHOULD be present.
If an appropriate default value can be associated with the desired
semantics, then a default statement SHOULD be present.
If a significant number of derived types are defined, and it is
anticipated that these data types will be reused by multiple modules,
then these derived types SHOULD be contained in a separate module or
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submodule, to allow easier reuse without unnecessary coupling.
The description statement MUST be present.
If the type definition semantics are defined in an external document,
then the reference statement SHOULD be present.
4.11. Object Definitions
The description statement MUST be present in the following body
statements:
o extension
o feature
o identity
o typedef
o grouping
o augment
o rpc
o notification
The description statement MUST be present in the following data
definition constructs:
o container
o leaf
o leaf-list
o list
o choice
o anyxml
If the object semantics are defined in an external document, then a
reference statement SHOULD be present.
The 'anyxml' construct MUST NOT be used within configuration data.
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If there are referential integrity constraints associated with the
desired semantics that can be represented with XPath, then one or
more must statements SHOULD be present.
For list and leaf-list objects, if the number of possible instances
is not required to be unbounded for all implementations, then the
max-elements statement SHOULD be present.
If any must or when statements are used within the object definition,
then the object description statement SHOULD describe the purpose of
each one.
4.12. RPC Definitions
The description statement MUST be present.
If the RPC method semantics are defined in an external document, then
a reference statement SHOULD be present.
If the RPC method impacts system behavior in some way, it SHOULD be
mentioned in the description statement.
If the RPC method is potentially harmful to system behavior in some
way, it MUST be mentioned in the Security Considerations section of
the document.
4.13. Notification Definitions
The description statement MUST be present.
If the notification semantics are defined in an external document,
then a reference statement SHOULD be present.
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5. IANA Considerations
There are no actions requested of IANA at this time.
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6. Security Considerations
This document defines documentation guidelines for NETCONF content
defined with the YANG data modeling language. It does not introduce
any new or increased security risks into the management system.
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7. Acknowledgments
The structure and contents of this document are adapted from
Guidelines for MIB Documents [RFC4181], by C. M. Heard.
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8. References
8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, January 2005.
[RFC4741] Enns, R., "NETCONF Configuration Protocol", RFC 4741,
December 2006.
[I-D.ietf-netmod-yang]
Bjorklund, M., "YANG - A data modeling language for
NETCONF", draft-ietf-netmod-yang-08 (work in progress),
October 2009.
[I-D.ietf-netmod-yang-types]
Schoenwaelder, J., "Common YANG Data Types",
draft-ietf-netmod-yang-types-04 (work in progress),
October 2009.
8.2. Informative References
[RFC4181] Heard, C., "Guidelines for Authors and Reviewers of MIB
Documents", BCP 111, RFC 4181, September 2005.
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Appendix A. Module Review Checklist
This section is adapted from RFC 4181.
The purpose of a YANG module review is to review the YANG module both
for technical correctness and for adherence to IETF documentation
requirements. The following checklist may be helpful when reviewing
a draft document:
1. I-D Boilerplate -- verify that the draft contains the required
Internet-Draft boilerplate (see
http://www.ietf.org/ietf/1id-guidelines.txt), including the
appropriate statement to permit publication as an RFC, and that
I-D boilerplate does not contain references or section numbers.
2. Abstract -- verify that the abstract does not contain
references, that it does not have a section number, and that its
content follows the guidelines in
http://www.ietf.org/ietf/1id-guidelines.txt.
3. YANG Module Boilerplate -- verify that the draft contains the
latest approved SNMP Network Management Framework boilerplate
from the OPS area web site
(http://www.ops.ietf.org/mib-boilerplate.html). [ed: real URL
TBD]
4. Security Considerations Section -- verify that the draft uses
the latest approved template from the OPS area web site
(http://www.ops.ietf.org/mib-security.html) and that the
guidelines therein have been followed.
5. IANA Considerations Section -- this section must always be
present. If the draft requires no action from the IANA, ensure
that this is explicitly noted. If the draft requires URI values
to be assigned, ensure that the IANA Considerations section
contains the information specified in [TBD] of these guidelines.
If the draft contains the initial version of an IANA-maintained
module, verify that the [TBD] invocation contains maintenance
instructions that comply with the requirements in RFC 2434. In
the latter case, the IANA Considerations section that will
appear in the RFC MUST contain a pointer to the actual IANA-
maintained module.
6. References -- verify that the references are properly divided
between normative and informative references, that RFC 2119 is
included as a normative reference if the terminology defined
therein is used in the document, that all references required by
the boilerplate are present, that all YANG modules containing
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imported items are cited as normative references, and that all
citations point to the most current RFCs unless there is a valid
reason to do otherwise (for example, it is OK to include an
informative reference to a previous version of a specification
to help explain a feature included for backward compatibility).
7. Copyright Notices -- verify that the draft contains an
abbreviated copyright notice in the description statement of
each YANG module or sub-module, and that it contains the full
copyright notice and disclaimer specified in Sections 5.4 and
5.5 of RFC 3978 at the end of the document. Make sure that the
correct year is used in all copyright dates.
8. IPR Notice -- if the draft does not contains a verbatim copy of
the IPR notice specified in Section 5 of RFC 3979, recommend
that the IPR notice be included.
9. Other Issues -- check for any issues mentioned in
http://www.ietf.org/ID-Checklist.html that are not covered
elsewhere.
10. Technical Content -- review the actual technical content for
compliance with the guidelines in this document. The use of a
YANG module compiler is recommended when checking for syntax
errors; see [YANG tool URL TBD] for more information. Checking
for correct syntax, however, is only part of the job. It is
just as important to actually read the YANG module document from
the point of view of a potential implementor. It is
particularly important to check that description statements are
sufficiently clear and unambiguous to allow interoperable
implementations to be created.
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Appendix B. YANG Module Template
<CODE BEGINS>
module ietf-template {
// replace this string with a unique namespace URN value
namespace
"urn:ietf:params:xml:ns:yang:ietf-template:DRAFT-02";
// replace this string, and try to pick a unique prefix
prefix "temp";
// import statements here: e.g.,
// import ietf-yang-types { prefix yang; }
// import ietf-inet-types { prefix inet; }
// identify the IETF working group if applicable
organization
"IETF NETMOD (NETCONF Data Modeling Language) Working Group";
// update this contact statement with your info
contact
"WG Web: <http://tools.ietf.org/wg/your-wg-name/>
WG List: <mailto:your-wg-name@ietf.org>
WG Chair: your-WG-chair
<mailto:your-WG-chair@example.com>
Editor: your-name
<mailto:your-email@example.com>";
// replace the first sentence in this description statement.
// replace the copyright notice with the most recent
// version, if it has been updated since the publication
// of this document
description
"This module defines a template for other YANG modules.
Copyright (c) 2009 IETF Trust and the persons identified as
the document authors. All rights reserved.
Redistribution and use in source and binary forms, with or
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without modification, are permitted provided that the
following conditions are met:
- Redistributions of source code must retain the above
copyright notice, this list of conditions and the
following disclaimer.
- Redistributions in binary form must reproduce the above
copyright notice, this list of conditions and the
following disclaimer in the documentation and/or other
materials provided with the distribution.
- Neither the name of Internet Society, IETF or IETF
Trust, nor the names of specific contributors, may be
used to endorse or promote products derived from this
software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
CONTRIBUTORS 'AS IS' AND ANY EXPRESS OR IMPLIED
WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
This version of this YANG module is part of RFC XXXX; see
the RFC itself for full legal notices.";
// RFC Ed.: replace XXXX with actual RFC number and remove this note
reference "RFC XXXX";
// RFC Ed.: remove this note
// Note: extracted from draft-ietf-netmod-yang-usage-02.txt
// replace YYYY-MM-DD with a real date (year-month-day)
// here is an example revision date: 2009-08-12
revision YYYY-MM-DD {
description
"Initial version";
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}
// extension statements
// feature statements
// identity statements
// typedef statements
// grouping statements
// data definition statements
// augment statements
// rpc statements
// notification statements
// DO NOT put deviation statements in a published module
}
<CODE ENDS>
Figure 2
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Appendix C. Change Log
C.1. 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.
C.2. 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.
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Author's Address
Andy Bierman
Netconf Central, Inc.
Simi Valley, CA
USA
Email: andy@netconfcentral.com
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