draft-ietf-netmod-module-tags-10.txt   rfc8819.txt 
Network Working Group C. Hopps Internet Engineering Task Force (IETF) C. Hopps
Internet-Draft LabN Consulting, L.L.C. Request for Comments: 8819 L. Berger
Updates: 8407 (if approved) L. Berger Updates: 8407 LabN Consulting, L.L.C.
Intended status: Standards Track LabN Consulting, LLC. Category: Standards Track D. Bogdanovic
Expires: September 1, 2020 D. Bogdanovic ISSN: 2070-1721 Volta Networks
Volta Networks January 2021
February 29, 2020
YANG Module Tags YANG Module Tags
draft-ietf-netmod-module-tags-10
Abstract Abstract
This document provides for the association of tags with YANG modules. This document provides for the association of tags with YANG modules.
The expectation is for such tags to be used to help classify and The expectation is for such tags to be used to help classify and
organize modules. A method for defining, reading and writing a organize modules. A method for defining, reading, and writing
modules tags is provided. Tags may be registered and assigned during modules tags is provided. Tags may be registered and assigned during
module definition; assigned by implementations; or dynamically module definition, assigned by implementations, or dynamically
defined and set by users. This document also provides guidance to defined and set by users. This document also provides guidance to
future model writers; as such, this document updates RFC8407. future model writers; as such, this document updates RFC 8407.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This is an Internet Standards Track document.
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://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). Further information on
Internet Standards is available in Section 2 of RFC 7841.
This Internet-Draft will expire on September 1, 2020. Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc8819.
Copyright Notice Copyright Notice
Copyright (c) 2020 IETF Trust and the persons identified as the Copyright (c) 2021 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
(https://trustee.ietf.org/license-info) in effect on the date of (https://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 . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction
1.1. Some possible use cases for YANG module tags . . . . . . 3 1.1. Some Possible Use Cases for YANG Module Tags
1.2. Conventions Used in This Document . . . . . . . . . . . . 4 1.2. Conventions Used in This Document
2. Tag Values . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Tag Values
2.1. IETF Tags . . . . . . . . . . . . . . . . . . . . . . . . 4 2.1. IETF Tags
2.2. Vendor Tags . . . . . . . . . . . . . . . . . . . . . . . 4 2.2. Vendor Tags
2.3. User Tags . . . . . . . . . . . . . . . . . . . . . . . . 5 2.3. User Tags
2.4. Reserved Tags . . . . . . . . . . . . . . . . . . . . . . 5 2.4. Reserved Tags
3. Tag Management . . . . . . . . . . . . . . . . . . . . . . . 5 3. Tag Management
3.1. Module Definition Tagging . . . . . . . . . . . . . . . . 5 3.1. Module Definition Tagging
3.2. Implementation Tagging . . . . . . . . . . . . . . . . . 5 3.2. Implementation Tagging
3.3. User Tagging . . . . . . . . . . . . . . . . . . . . . . 5 3.3. User Tagging
4. Tags Module Structure . . . . . . . . . . . . . . . . . . . . 6 4. Tags Module Structure
4.1. Tags Module Tree . . . . . . . . . . . . . . . . . . . . 6 4.1. Tags Module Tree
4.2. YANG Module . . . . . . . . . . . . . . . . . . . . . . . 6 4.2. YANG Module
5. Other Classifications . . . . . . . . . . . . . . . . . . . . 9 5. Other Classifications
6. Guidelines to Model Writers . . . . . . . . . . . . . . . . . 9 6. Guidelines to Model Writers
6.1. Define Standard Tags . . . . . . . . . . . . . . . . . . 9 6.1. Define Standard Tags
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 7. IANA Considerations
7.1. YANG Module Tag Prefixes Registry . . . . . . . . . . . . 9 7.1. YANG Module Tag Prefixes Registry
7.2. IETF YANG Module Tags Registry . . . . . . . . . . . . . 10 7.2. IETF YANG Module Tags Registry
7.3. Updates to the IETF XML Registry . . . . . . . . . . . . 12 7.3. Updates to the IETF XML Registry
7.4. Updates to the YANG Module Names Registry . . . . . . . . 12 7.4. Updates to the YANG Module Names Registry
8. Security Considerations . . . . . . . . . . . . . . . . . . . 13 8. Security Considerations
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 13 9. References
9.1. Normative References . . . . . . . . . . . . . . . . . . 13 9.1. Normative References
9.2. Informative References . . . . . . . . . . . . . . . . . 14 9.2. Informative References
Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 15 Appendix A. Examples
Appendix B. Acknowledgements . . . . . . . . . . . . . . . . . . 15 Appendix B. Non-NMDA State Module
Appendix C. Non-NMDA State Module. . . . . . . . . . . . . . . . 15 Acknowledgements
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 18 Authors' Addresses
1. Introduction 1. Introduction
The use of tags for classification and organization is fairly The use of tags for classification and organization is fairly
ubiquitous not only within IETF protocols, but in the internet itself ubiquitous not only within IETF protocols but in the internet itself
(e.g., "#hashtags"). One benefit of using tags for organization over (e.g., "#hashtags"). One benefit of using tags for organization over
a rigid structure is that it is more flexible and can more easily a rigid structure is that it is more flexible and can more easily
adapt over time as technologies evolve. Tags can be usefully adapt over time as technologies evolve. Tags can be usefully
registered, but they can also serve as a non-registered mechanism registered, but they can also serve as a non-registered mechanism
available for users to define themselves. This document provides a available for users to define themselves. This document provides a
mechanism to define tags and associate them with YANG modules in a mechanism to define tags and associate them with YANG modules in a
flexible manner. In particular, tags may be registered as well as flexible manner. In particular, tags may be registered as well as
assigned during module definition; assigned by implementations; or assigned during module definition, assigned by implementations, or
dynamically defined and set by users. dynamically defined and set by users.
This document defines a YANG module [RFC7950] which provides a list This document defines a YANG module [RFC7950] that provides a list of
of module entries to allow for adding or removing of tags as well as module entries to allow for adding or removing tags as well as
viewing the set of tags associated with a module. viewing the set of tags associated with a module.
This document defines an extension statement to be used to indicate This document defines an extension statement to indicate tags that
tags that SHOULD be added by the module implementation automatically SHOULD be added by the module implementation automatically (i.e.,
(i.e., outside of configuration). outside of configuration).
This document also defines an IANA registry for tag prefixes as well This document also defines an IANA registry for tag prefixes as well
as a set of globally assigned tags. as a set of globally assigned tags.
Section 6 provides guidelines for authors of YANG data models. Section 6 provides guidelines for authors of YANG data models.
This document updates [RFC8407]. This document updates [RFC8407].
The YANG data model in this document conforms to the Network The YANG data model in this document conforms to the Network
Management Datastore Architecture defined in [RFC8342]. Management Datastore Architecture (NMDA) defined in [RFC8342].
1.1. Some possible use cases for YANG module tags 1.1. Some Possible Use Cases for YANG Module Tags
During this documents's development there were requests for example During this document's development, there were requests for example
uses of module tags. The following are a few example use cases for uses of module tags. The following are a few example use cases for
tags. This list is certainly not exhaustive. tags. This list is certainly not exhaustive.
One example use of tags would be to help filter different discrete One example use of tags would be to help filter different discrete
categories of YANG modules supported by a device. For example, if categories of YANG modules supported by a device. For example, if
modules are suitably tagged, then an XPath query can be used to list modules are suitably tagged, then an XPath query can be used to list
all of the vendor modules supported by a device. all of the vendor modules supported by a device.
Tags can also be used to help coordination when multiple semi- Tags can also be used to help coordination when multiple, semi-
independent clients are interacting with the same devices. For independent clients are interacting with the same devices. For
example, one management client could mark that some modules should example, one management client could mark that some modules should
not be used because they have not been verified to behave correctly, not be used because they have not been verified to behave correctly,
so that other management clients avoid querying the data associated so that other management clients avoid querying the data associated
with those modules. with those modules.
Tag classification is useful for users searching module repositories Tag classification is useful for users searching module repositories
(e.g., YANG catalog). A query restricted to the 'ietf:routing' (e.g., YANG catalog). A query restricted to the 'ietf:routing'
module tag could be used to return only the IETF YANG modules module tag could be used to return only the IETF YANG modules
associated with routing. Without tags, a user would need to know the associated with routing. Without tags, a user would need to know the
name of all the IETF routing protocol YANG modules. name of all the IETF routing protocol YANG modules.
Future management protocol extensions could allow for filtering Future management protocol extensions could allow for filtering
queries of configuration or operational state on a server based on queries of configuration or operational state on a server based on
tags. For example, return all operational state related to system- tags (for example, return all operational state related to system
management. management).
1.2. Conventions Used in This Document 1.2. Conventions Used in This Document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in "OPTIONAL" in this document are to be interpreted as described in
[RFC2119] [RFC8174] when, and only when, they appear in all capitals, BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
as shown here. capitals, as shown here.
2. Tag Values 2. Tag Values
All tags SHOULD begin with a prefix indicating who owns their All tags SHOULD begin with a prefix indicating who owns their
definition. An IANA registry (Section 7.1) is used to support definition. An IANA registry (Section 7.1) is used to support
registering tag prefixes. Currently 3 prefixes are defined. No registering tag prefixes. Currently, three prefixes are defined. No
further structure is imposed by this document on the value following further structure is imposed by this document on the value following
the registered prefix, and the value can contain any YANG type the registered prefix, and the value can contain any YANG type
'string' characters except carriage-returns, newlines and tabs. 'string' characters except carriage returns, newlines, and tabs.
Again, except for the conflict-avoiding prefix, this document is not Again, except for the conflict-avoiding prefix, this document is
specifying any structure on (i.e., restricting) the tag values on purposefully not specifying any structure on (i.e., restricting) the
purpose. The intent is to avoid arbitrarily restricting the values tag values. The intent is to avoid arbitrarily restricting the
that designers, implementers and users can use. As a result of this values that designers, implementers, and users can use. As a result
choice, designers, implementers, and users are free to add or not add of this choice, designers, implementers, and users are free to add or
any structure they may require to their own tag values. not add any structure they may require to their own tag values.
2.1. IETF Tags 2.1. IETF Tags
An IETF tag is a tag that has the prefix "ietf:". All IETF tags are An IETF tag is a tag that has the prefix "ietf:". All IETF tags are
registered with IANA in a registry defined later in this document registered with IANA in a registry defined later in this document
(Section 7.2). (Section 7.2).
2.2. Vendor Tags 2.2. Vendor Tags
A vendor tag is a tag that has the prefix "vendor:". These tags are A vendor tag is a tag that has the prefix "vendor:". These tags are
defined by the vendor that implements the module, and are not defined by the vendor that implements the module and are not
registered; however, it is RECOMMENDED that the vendor include extra registered; however, it is RECOMMENDED that the vendor include extra
identification in the tag to avoid collisions such as using the identification in the tag to avoid collisions, such as using the
enterpise or organization name following the "vendor:" prefix (e.g., enterprise or organization name following the "vendor:" prefix (e.g.,
vendor:example.com:vendor-defined-classifier). vendor:example.com:vendor-defined-classifier).
2.3. User Tags 2.3. User Tags
A user tag is any tag that has the prefix "user:". These tags are A user tag is any tag that has the prefix "user:". These tags are
defined by the user/administrator and are not meant to be registered. defined by the user/administrator and are not meant to be registered.
Users are not required to use the "user:" prefix; however, doing so Users are not required to use the "user:" prefix; however, doing so
is RECOMMENDED as it helps avoid collisions. is RECOMMENDED as it helps avoid collisions.
2.4. Reserved Tags 2.4. Reserved Tags
Any tag not starting with the prefix "ietf:", "vendor:" or "user:" is Any tag not starting with the prefix "ietf:", "vendor:", or "user:"
reserved for future use. These tag values are not invalid, but is reserved for future use. These tag values are not invalid but
simply reserved in the context of specifications (e.g., RFCs). simply reserved in the context of specifications (e.g., RFCs).
3. Tag Management 3. Tag Management
Tags can become associated with a module in a number of ways. Tags Tags can become associated with a module in a number of ways. Tags
may be defined and associated at module design time, at may be defined and associated at module design time, at
implementation time, or via user administrative control. As the main implementation time, or via user administrative control. As the main
consumer of tags are users, users may also remove any tag, no matter consumer of tags are users, users may also remove any tag, no matter
how the tag became associated with a module. how the tag became associated with a module.
3.1. Module Definition Tagging 3.1. Module Definition Tagging
A module definition MAY indicate a set of tags to be added by the A module definition MAY indicate a set of tags to be added by the
module implementer. These design time tags are indicated using the module implementer. These design-time tags are indicated using the
module-tag extension statement. module-tag extension statement.
If the module is defined in an IETF standards track document, the If the module is defined in an IETF Standards Track document, the
tags MUST be IETF Tags (2.1). Thus, new modules can drive the tags MUST be IETF tags (Section 2.1). Thus, new modules can drive
addition of new IETF tags to the IANA registry defined in the addition of new IETF tags to the IANA registry defined in
Section 7.2, and the IANA registry can serve as a check against Section 7.2, and the IANA registry can serve as a check against
duplication. duplication.
3.2. Implementation Tagging 3.2. Implementation Tagging
An implementation MAY include additional tags associated with a An implementation MAY include additional tags associated with a
module. These tags SHOULD be IETF Tags (i.e., registered) or vendor module. These tags SHOULD be IETF tags (i.e., registered) or vendor-
specific tags. specific tags.
3.3. User Tagging 3.3. User Tagging
Tags of any kind, with or without a prefix, can be assigned and Tags of any kind, with or without a prefix, can be assigned and
removed by the user using normal configuration mechanisms. In order removed by the user using normal configuration mechanisms. In order
to remove a tag from the operational datastore the user adds a to remove a tag from the operational datastore, the user adds a
matching "masked-tag" entry for a given module. matching "masked-tag" entry for a given module.
4. Tags Module Structure 4. Tags Module Structure
4.1. Tags Module Tree 4.1. Tags Module Tree
The tree associated with the "ietf-module-tags" module follows. The The tree associated with the "ietf-module-tags" module follows. The
meaning of the symbols can be found in [RFC8340]. meaning of the symbols can be found in [RFC8340].
module: ietf-module-tags module: ietf-module-tags
+--rw module-tags +--rw module-tags
+--rw module* [name] +--rw module* [name]
+--rw name yang:yang-identifier +--rw name yang:yang-identifier
+--rw tag* tag +--rw tag* tag
+--rw masked-tag* tag +--rw masked-tag* tag
Figure 1: YANG Module Tags Tree Diagram Figure 1: YANG Module Tags Tree Diagram
4.2. YANG Module 4.2. YANG Module
<CODE BEGINS> file "ietf-module-tags@2020-02-29.yang" <CODE BEGINS> file "ietf-module-tags@2021-01-04.yang"
module ietf-module-tags { module ietf-module-tags {
yang-version 1.1; yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-module-tags"; namespace "urn:ietf:params:xml:ns:yang:ietf-module-tags";
prefix tags; prefix tags;
import ietf-yang-types { import ietf-yang-types {
prefix yang; prefix yang;
} }
organization organization
"IETF NetMod Working Group (NetMod)"; "IETF NetMod Working Group (NetMod)";
contact contact
"WG Web: <https://tools.ietf.org/wg/netmod/> "WG Web: <https://datatracker.ietf.org/wg/netmod/>
WG List: <mailto:netmod@ietf.org> WG List: <mailto:netmod@ietf.org>
Author: Christian Hopps Author: Christian Hopps
<mailto:chopps@chopps.org> <mailto:chopps@chopps.org>
Author: Lou Berger Author: Lou Berger
<mailto:lberger@labn.net> <mailto:lberger@labn.net>
Author: Dean Bogdanovic Author: Dean Bogdanovic
<ivandean@gmail.com>"; <mailto:ivandean@gmail.com>";
// RFC Ed.: replace XXXX with actual RFC number and
// remove this note.
description description
"This module describes a mechanism associating tags with YANG "This module describes a mechanism associating tags with YANG
modules. Tags may be IANA assigned or privately defined. modules. Tags may be IANA assigned or privately defined.
Copyright (c) 2019 IETF Trust and the persons identified as Copyright (c) 2021 IETF Trust and the persons identified as
authors of the code. All rights reserved. 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 to without modification, is permitted pursuant to, and subject to
the license terms contained in, the Simplified BSD License set the license terms contained in, the Simplified BSD License set
forth in Section 4.c of the IETF Trust's Legal Provisions forth in Section 4.c of the IETF Trust's Legal Provisions
Relating to IETF Documents Relating to IETF Documents
(https://trustee.ietf.org/license-info). (https://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC XXXX This version of this YANG module is part of RFC 8819
(https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself (https://www.rfc-editor.org/info/rfc8819); see the RFC itself
for full legal notices. for full legal notices.
The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED', NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED',
'MAY', and 'OPTIONAL' in this document are to be interpreted as 'MAY', and 'OPTIONAL' in this document are to be interpreted as
described in BCP 14 (RFC 2119) (RFC 8174) when, and only when, described in BCP 14 (RFC 2119) (RFC 8174) when, and only when,
they appear in all capitals, as shown here."; they appear in all capitals, as shown here.";
// RFC Ed.: update the date below with the date of RFC publication revision 2021-01-04 {
// and RFC number and remove this note.
revision 2020-02-29 {
description description
"Initial revision."; "Initial revision.";
reference "RFC XXXX: YANG Module Tags"; reference
"RFC 8819: YANG Module Tags";
} }
typedef tag { typedef tag {
type string { type string {
length "1..max"; length "1..max";
pattern '[\S ]+'; pattern '[\S ]+';
} }
description description
"A tag is a type 'string' value that does not include carriage "A tag is a type of 'string' value that does not include
return, newline or tab characters. It SHOULD begin with a carriage return, newline, or tab characters. It SHOULD begin
registered prefix; however, tags without a registered prefix with a registered prefix; however, tags without a registered
SHOULD NOT be treated as invalid."; prefix SHOULD NOT be treated as invalid.";
} }
extension module-tag { extension module-tag {
argument tag; argument tag;
description description
"The argument 'tag' is of type 'tag'. This extension statement "The argument 'tag' is of type 'tag'. This extension statement
is used by module authors to indicate the tags that SHOULD be is used by module authors to indicate the tags that SHOULD be
added automatically by the system. As such the origin of the added automatically by the system. As such, the origin of the
value for the pre-defined tags should be set to 'system' value for the predefined tags should be set to 'system'
[RFC8342]."; [RFC8342].";
} }
container module-tags { container module-tags {
description description
"Contains the list of modules and their associated tags"; "Contains the list of modules and their associated tags.";
list module { list module {
key "name"; key "name";
description description
"A list of modules and their associated tags"; "A list of modules and their associated tags.";
leaf name { leaf name {
type yang:yang-identifier; type yang:yang-identifier;
mandatory true; mandatory true;
description description
"The YANG module name."; "The YANG module name.";
} }
leaf-list tag { leaf-list tag {
type tag; type tag;
description description
"Tags associated with the module. See the IANA 'YANG Module "Tags associated with the module. See the IANA 'YANG
Tag Prefixes' registry for reserved prefixes and the IANA Module Tag Prefixes' registry for reserved prefixes and
'IETF YANG Module Tags' registry for IETF tags. the IANA 'IETF YANG Module Tags' registry for IETF tags.
The 'operational' state [RFC8342] view of this list is The 'operational' state [RFC8342] view of this list is
constructed using the following steps: constructed using the following steps:
1) System tags (i.e., tags of 'system' origin) are added. 1) System tags (i.e., tags of 'system' origin) are added.
2) User configured tags (i.e., tags of 'intended' origin) 2) User-configured tags (i.e., tags of 'intended' origin)
are added. are added.
3) Any tag that is equal to a masked-tag is removed."; 3) Any tag that is equal to a masked-tag is removed.";
} }
leaf-list masked-tag { leaf-list masked-tag {
type tag; type tag;
description description
"The list of tags that should not be associated with this "The list of tags that should not be associated with this
module. The user can remove (mask) tags from the module. The user can remove (mask) tags from the
operational state datastore [RFC8342] by adding them to operational state datastore [RFC8342] by adding them to
this list. It is not an error to add tags to this list this list. It is not an error to add tags to this list
that are not associated with the module, but they have no that are not associated with the module, but they have no
operational effect."; operational effect.";
} }
} }
} }
} }
<CODE ENDS> <CODE ENDS>
Figure 2: Module Tags Module
Figure 2: Module Tags Module
5. Other Classifications 5. Other Classifications
It is worth noting that a different YANG module classification It is worth noting that a different YANG module classification
document exists [RFC8199]. That document only classifies modules in document exists [RFC8199]. That document only classifies modules in
a logical manner and does not define tagging or any other mechanisms. a logical manner and does not define tagging or any other mechanisms.
It divides YANG modules into two categories (service or element) and It divides YANG modules into two categories (service or element) and
then into one of three origins: standard, vendor or user. It does then into one of three origins: standard, vendor, or user. It does
provide a good way to discuss and identify modules in general. This provide a good way to discuss and identify modules in general. This
document defines IETF tags to support [RFC8199] style classification. document defines IETF tags to support the classification style
described in [RFC8199].
6. Guidelines to Model Writers 6. Guidelines to Model Writers
This section updates [RFC8407]. This section updates [RFC8407].
6.1. Define Standard Tags 6.1. Define Standard Tags
A module MAY indicate, using module-tag extension statements, a set A module MAY indicate, using module-tag extension statements, a set
of tags that are to be automatically associated with it (i.e., not of tags that are to be automatically associated with it (i.e., not
added through configuration). added through configuration).
module example-module { module example-module {
namespace "https://example.com/yang/example";
prefix "ex";
//... //...
import module-tags { prefix tags; } import module-tags { prefix tags; }
tags:module-tag "ietf:some-new-tag"; tags:module-tag "ietf:some-new-tag";
tags:module-tag "ietf:some-other-tag"; tags:module-tag "ietf:some-other-tag";
// ... // ...
} }
The module writer can use existing standard tags, or use new tags The module writer can use existing standard tags or use new tags
defined in the model definition, as appropriate. For IETF defined in the model definition, as appropriate. For IETF
standardized modules new tags MUST be assigned in the IANA registry standardized modules, new tags MUST be assigned in the IANA registry
defined below, see Section 7.2. defined below, see Section 7.2.
7. IANA Considerations 7. IANA Considerations
7.1. YANG Module Tag Prefixes Registry 7.1. YANG Module Tag Prefixes Registry
IANA is asked to create a new registry "YANG Module Tag Prefixes" IANA has created the "YANG Module Tag Prefixes" subregistry in the
grouped under a new "Protocol" category named "YANG Module Tags". "YANG Module Tags" registry.
This registry allocates tag prefixes. All YANG module tags SHOULD This registry allocates tag prefixes. All YANG module tags SHOULD
begin with one of the prefixes in this registry. begin with one of the prefixes in this registry.
Prefix entries in this registry should be short strings consisting of Prefix entries in this registry should be short strings consisting of
lowercase ASCII alpha-numeric characters and a final ":" character. lowercase ASCII alpha-numeric characters and a final ":" character.
The allocation policy for this registry is Specification Required The allocation policy for this registry is Specification Required
[RFC8126]. The Reference and Assignee values should be sufficient to [RFC8126]. The Reference and Assignee values should be sufficient to
identify and contact the organization that has been allocated the identify and contact the organization that has been allocated the
prefix. prefix.
The initial values for this registry are as follows. The initial values for this registry are as follows.
+---------+----------------------------------+-----------+----------+ +=========+========================+===========+==========+
| Prefix | Description | Reference | Assignee | | Prefix | Description | Reference | Assignee |
+---------+----------------------------------+-----------+----------+ +=========+========================+===========+==========+
| ietf: | IETF Tags allocated in the IANA | [This | IETF | | ietf: | IETF tags allocated in | RFC 8819 | IETF |
| | IETF YANG Module Tags registry. | document] | | | | the IANA "IETF YANG | | |
| | | | | | | Module Tags" registry. | | |
| vendor: | Non-registered tags allocated by | [This | IETF | +---------+------------------------+-----------+----------+
| | the module implementer. | document] | | | vendor: | Non-registered tags | RFC 8819 | IETF |
| | | | | | | allocated by the | | |
| user: | Non-registered tags allocated by | [This | IETF | | | module implementer. | | |
| | and for the user. | document] | | +---------+------------------------+-----------+----------+
+---------+----------------------------------+-----------+----------+ | user: | Non-registered tags | RFC 8819 | IETF |
| | allocated by and for | | |
| | the user. | | |
+---------+------------------------+-----------+----------+
Other standards organizations (SDOs) wishing to allocate their own Table 1
set of tags should allocate a prefix from this registry.
Other standards development organizations (SDOs) wishing to allocate
their own set of tags should allocate a prefix from this registry.
7.2. IETF YANG Module Tags Registry 7.2. IETF YANG Module Tags Registry
IANA is asked to create a new registry "IETF YANG Module Tags" IANA has created the "IETF YANG Module Tags" subregistry within the
grouped under a new "Protocol" category "IETF YANG Module Tags". "YANG Module Tags" registry . This registry appears below the "YANG
This registry should be included below "YANG Module Tag Prefixes" Module Tag Prefixes" registry.
when listed on the same page.
This registry allocates tags that have the registered prefix "ietf:". This registry allocates tags that have the registered prefix "ietf:".
New values should be well considered and not achievable through a New values should be well considered and not achievable through a
combination of already existing IETF tags. IANA assigned tags must combination of already existing IETF tags. IANA assigned tags must
conform to Net-Unicode as defined in [RFC5198] and they shall not conform to Net-Unicode as defined in [RFC5198], and they shall not
need normalization. need normalization.
The allocation policy for this registry is IETF Review [RFC8126]. The allocation policy for this registry is IETF Review [RFC8126].
The initial values for this registry are as follows. The initial values for this registry are as follows.
+----------------------------+--------------------------+-----------+ +============================+=======================+===========+
| Tag | Description | Reference | | Tag | Description | Reference |
+----------------------------+--------------------------+-----------+ +============================+=======================+===========+
| ietf:network-element-class | [RFC8199] network | [RFC8199] | | ietf:network-element-class | Network element as | [RFC8199] |
| | element. | | | | defined in [RFC8199]. | |
| | | | +----------------------------+-----------------------+-----------+
| ietf:network-service-class | [RFC8199] network | [RFC8199] | | ietf:network-service-class | Network service as | [RFC8199] |
| | service. | | | | defined in [RFC8199]. | |
| | | | +----------------------------+-----------------------+-----------+
| ietf:sdo-defined-class | Module is defined by a | [RFC8199] | | ietf:sdo-defined-class | Module is defined by | [RFC8199] |
| | standards organization. | | | | a standards | |
| | | | | | organization. | |
| ietf:vendor-defined-class | Module is defined by a | [RFC8199] | +----------------------------+-----------------------+-----------+
| | vendor. | | | ietf:vendor-defined-class | Module is defined by | [RFC8199] |
| | | | | | a vendor. | |
| ietf:user-defined-class | Module is defined by the | [RFC8199] | +----------------------------+-----------------------+-----------+
| | user. | | | ietf:user-defined-class | Module is defined by | [RFC8199] |
| | | | | | the user. | |
| ietf:hardware | Relates to hardware | [This | +----------------------------+-----------------------+-----------+
| | (e.g., inventory). | document] | | ietf:hardware | Relates to hardware | RFC 8819 |
| | | | | | (e.g., inventory). | |
| ietf:software | Relates to software | [This | +----------------------------+-----------------------+-----------+
| | (e.g., installed OS). | document] | | ietf:software | Relates to software | RFC 8819 |
| | | | | | (e.g., installed OS). | |
| ietf:protocol | Represents a protocol | [This | +----------------------------+-----------------------+-----------+
| | (often combined with | document] | | ietf:protocol | Represents a protocol | RFC 8819 |
| | another tag to refine). | | | | (often combined with | |
| | | | | | another tag to | |
| ietf:qos | Relates to quality of | [This | | | refine). | |
| | service. | document] | +----------------------------+-----------------------+-----------+
| | | | | ietf:qos | Relates to quality of | RFC 8819 |
| ietf:network-service-app | Relates to a network | [This | | | service. | |
| | service application | document] | +----------------------------+-----------------------+-----------+
| | (e.g., an NTP server, | | | ietf:network-service-app | Relates to a network | RFC 8819 |
| | DNS server, DHCP server, | | | | service application | |
| | etc). | | | | (e.g., an NTP server, | |
| | | | | | DNS server, DHCP | |
| ietf:system-management | Relates to system | [This | | | server, etc.). | |
| | management (e.g., a | document] | +----------------------------+-----------------------+-----------+
| | system management | | | ietf:system-management | Relates to system | RFC 8819 |
| | protocol such as syslog, | | | | management (e.g., a | |
| | TACAC+, SNMP, netconf, | | | | system management | |
| | ...). | | | | protocol such as | |
| | | | | | syslog, TACAC+, SNMP, | |
| ietf:oam | Relates to Operations, | [This | | | NETCONF, etc.). | |
| | Administration, and | document] | +----------------------------+-----------------------+-----------+
| | Maintenance (e.g., BFD). | | | ietf:oam | Relates to | RFC 8819 |
| | | | | | Operations, | |
| ietf:routing | Relates to routing. | [This | | | Administration, and | |
| | | document] | | | Maintenance (e.g., | |
| | | | | | BFD). | |
| ietf:security | Related to security. | [This | +----------------------------+-----------------------+-----------+
| | | document] | | ietf:routing | Relates to routing. | RFC 8819 |
| | | | +----------------------------+-----------------------+-----------+
| ietf:signaling | Relates to control plane | [This | | ietf:security | Related to security. | RFC 8819 |
| | signaling. | document] | +----------------------------+-----------------------+-----------+
| | | | | ietf:signaling | Relates to control- | RFC 8819 |
| ietf:link-management | Relates to link | [This | | | plane signaling. | |
| | management. | document] | +----------------------------+-----------------------+-----------+
+----------------------------+--------------------------+-----------+ | ietf:link-management | Relates to link | RFC 8819 |
| | management. | |
+----------------------------+-----------------------+-----------+
Table 2
7.3. Updates to the IETF XML Registry 7.3. Updates to the IETF XML Registry
This document registers a URI in the "IETF XML Registry" [RFC3688]. This document registers a URI in the "IETF XML Registry" [RFC3688].
Following the format in [RFC3688], the following registrations have Following the format in [RFC3688], the following registrations have
been made: been made:
URI: URI: urn:ietf:params:xml:ns:yang:ietf-module-tags
urn:ietf:params:xml:ns:yang:ietf-module-tags Registrant Contact: The IESG.
XML: N/A; the requested URI is an XML namespace.
Registrant Contact:
The IESG.
XML:
N/A; the requested URI is an XML namespace.
URI:
urn:ietf:params:xml:ns:yang:ietf-module-tags-state
Registrant Contact:
The IESG.
XML: URI: urn:ietf:params:xml:ns:yang:ietf-module-tags-state
N/A; the requested URI is an XML namespace. Registrant Contact: The IESG.
XML: N/A; the requested URI is an XML namespace.
7.4. Updates to the YANG Module Names Registry 7.4. Updates to the YANG Module Names Registry
This document registers two YANG modules in the "YANG Module Names" This document registers two YANG modules in the "YANG Module Names"
registry [RFC6020]. Following the format in [RFC6020], the following registry [RFC6020]. Following the format in [RFC6020], the following
registration have been made: registrations have been made:
name:
ietf-module-tags
namespace:
urn:ietf:params:xml:ns:yang:ietf-module-tags
prefix:
tags
reference:
RFC XXXX (RFC Ed.: replace XXX with actual RFC number and remove
this note.)
name:
ietf-module-tags-state
namespace:
urn:ietf:params:xml:ns:yang:ietf-module-tags-state
prefix: name: ietf-module-tags
tags namespace: urn:ietf:params:xml:ns:yang:ietf-module-tags
prefix: tags
reference: RFC 8819
reference: name: ietf-module-tags-state
RFC XXXX (RFC Ed.: replace XXX with actual RFC number and remove namespace: urn:ietf:params:xml:ns:yang:ietf-module-tags-state
this note.) prefix: tags-s
reference: RFC 8819
8. Security Considerations 8. Security Considerations
The YANG module defined in this memo is designed to be accessed via The YANG module defined in this memo is designed to be accessed via
the NETCONF protocol [RFC6241]. The lowest NETCONF layer is the the NETCONF protocol [RFC6241]. The lowest NETCONF layer is the
secure transport layer and the mandatory-to-implement secure secure transport layer and the mandatory-to-implement secure
transport is SSH [RFC6242]. transport is Secure Shell (SSH) [RFC6242].
This document adds the ability to associate tag meta-data with YANG This document adds the ability to associate tag metadata with YANG
modules. This document does not define any actions based on these modules. This document does not define any actions based on these
associations, and none are yet defined, and therefore it does not by associations, and none are yet defined; therefore, it does not by
itself introduce any new security considerations directly. itself introduce any new security considerations directly.
Users of the tag-meta data may define various actions to be taken Users of the tag metadata may define various actions to be taken
based on the tag meta-data. These actions and their definitions are based on the tag metadata. These actions and their definitions are
outside the scope of this document. Users will need to consider the outside the scope of this document. Users will need to consider the
security implications of any actions they choose to define, including security implications of any actions they choose to define, including
the potential for a tag to get 'masked' by another user. the potential for a tag to get 'masked' by another user.
9. References 9. References
9.1. Normative References 9.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
skipping to change at page 15, line 8 skipping to change at line 645
Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011, Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011,
<https://www.rfc-editor.org/info/rfc6242>. <https://www.rfc-editor.org/info/rfc6242>.
[RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams", [RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams",
BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018, BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018,
<https://www.rfc-editor.org/info/rfc8340>. <https://www.rfc-editor.org/info/rfc8340>.
Appendix A. Examples Appendix A. Examples
The following is a fictional NETCONF example result from a query of The following is a fictional NETCONF example result from a query of
the module tags list. For the sake of brevity only a few module the module tags list. For the sake of brevity, only a few module
results are imagined. results are shown.
<ns0:data xmlns:ns0="urn:ietf:params:xml:ns:netconf:base:1.0">
<t:module-tags xmlns:t="urn:ietf:params:xml:ns:yang:ietf-module-tags">
<t:module>
<t:name>ietf-bfd</t:name>
<t:tag>ietf:network-element-class</t:tag>
<t:tag>ietf:oam</t:tag>
<t:tag>ietf:protocol</t:tag>
<t:tag>ietf:sdo-defined-class</t:tag>
</t:module>
<t:module>
<t:name>ietf-isis</t:name>
<t:tag>ietf:network-element-class</t:tag>
<t:tag>ietf:protocol</t:tag>
<t:tag>ietf:sdo-defined-class</t:tag>
<t:tag>ietf:routing</t:tag>
</t:module>
<t:module>
<t:name>ietf-ssh-server</t:name>
<t:tag>ietf:network-element-class</t:tag>
<t:tag>ietf:protocol</t:tag>
<t:tag>ietf:sdo-defined-class</t:tag>
<t:tag>ietf:system-management</t:tag>
</t:module>
</t:module-tags>
</ns0:data>
Figure 3: Example NETCONF Query Output
Appendix B. Acknowledgements <ns0:data xmlns:ns0="urn:ietf:params:xml:ns:netconf:base:1.0">
<t:module-tags
xmlns:t="urn:ietf:params:xml:ns:yang:ietf-module-tags">
<t:module>
<t:name>ietf-bfd</t:name>
<t:tag>ietf:network-element-class</t:tag>
<t:tag>ietf:oam</t:tag>
<t:tag>ietf:protocol</t:tag>
<t:tag>ietf:sdo-defined-class</t:tag>
</t:module>
<t:module>
<t:name>ietf-isis</t:name>
<t:tag>ietf:network-element-class</t:tag>
<t:tag>ietf:protocol</t:tag>
<t:tag>ietf:sdo-defined-class</t:tag>
<t:tag>ietf:routing</t:tag>
</t:module>
<t:module>
<t:name>ietf-ssh-server</t:name>
<t:tag>ietf:network-element-class</t:tag>
<t:tag>ietf:protocol</t:tag>
<t:tag>ietf:sdo-defined-class</t:tag>
<t:tag>ietf:system-management</t:tag>
</t:module>
</t:module-tags>
</ns0:data>
Special thanks to Robert Wilton for his help improving the Figure 3: Example NETCONF Query Output
introduction and providing the example use cases, as well as
generating the non-NMDA module.
Appendix C. Non-NMDA State Module. Appendix B. Non-NMDA State Module
As per [RFC8407] the following is a non-NMDA module to support As per [RFC8407], the following is a non-NMDA module to support
viewing the operational state for non-NMDA compliant servers. viewing the operational state for non-NMDA compliant servers.
<CODE BEGINS> file "ietf-module-tags-state@2020-02-29.yang" <CODE BEGINS> file "ietf-module-tags-state@2021-01-04.yang"
module ietf-module-tags-state { module ietf-module-tags-state {
yang-version 1.1; yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-module-tags-state"; namespace "urn:ietf:params:xml:ns:yang:ietf-module-tags-state";
prefix tags-s; prefix tags-s;
import ietf-yang-types {
prefix yang;
}
import ietf-module-tags {
prefix tags;
}
organization import ietf-yang-types {
"IETF NetMod Working Group (NetMod)"; prefix yang;
contact }
"WG Web: <https://tools.ietf.org/wg/netmod/> import ietf-module-tags {
WG List: <mailto:netmod@ietf.org> prefix tags;
}
Author: Christian Hopps organization
<mailto:chopps@chopps.org> "IETF NetMod Working Group (NetMod)";
contact
"WG Web: <https://datatracker.ietf.org/wg/netmod/>
WG List: <mailto:netmod@ietf.org>
Author: Lou Berger Author: Christian Hopps
<mailto:lberger@labn.net> <mailto:chopps@chopps.org>
Author: Dean Bogdanovic Author: Lou Berger
<ivandean@gmail.com>"; <mailto:lberger@labn.net>
// RFC Ed.: replace XXXX with actual RFC number and Author: Dean Bogdanovic
// remove this note. <mailto:ivandean@gmail.com>";
description description
"This module describes a mechanism associating tags with YANG "This module describes a mechanism associating tags with YANG
modules. Tags may be IANA assigned or privately defined. modules. Tags may be IANA assigned or privately defined.
This is a temporary non-NMDA module that is for use by This is a temporary non-NMDA module that is for use by
implementations that don't yet support NMDA. implementations that don't yet support NMDA.
Copyright (c) 2019 IETF Trust and the persons identified as Copyright (c) 2021 IETF Trust and the persons identified as
authors of the code. All rights reserved. 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 to without modification, is permitted pursuant to, and subject to
the license terms contained in, the Simplified BSD License set the license terms contained in, the Simplified BSD License set
forth in Section 4.c of the IETF Trust's Legal Provisions forth in Section 4.c of the IETF Trust's Legal Provisions
Relating to IETF Documents Relating to IETF Documents
(https://trustee.ietf.org/license-info). (https://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC XXXX This version of this YANG module is part of RFC 8819
(https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself (https://www.rfc-editor.org/info/rfc8819); see the RFC itself
for full legal notices. for full legal notices.";
The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL revision 2021-01-04 {
NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED', description
'MAY', and 'OPTIONAL' in this document are to be interpreted as "Initial revision.";
described in BCP 14 (RFC 2119) (RFC 8174) when, and only when, reference
they appear in all capitals, as shown here."; "RFC 8819: YANG Module Tags";
}
// RFC Ed.: update the date below with the date of RFC publication container module-tags-state {
// and RFC number and remove this note. config false;
status deprecated;
description
"Contains the list of modules and their associated tags.";
list module {
key "name";
status deprecated;
description
"A list of modules and their associated tags.";
leaf name {
type yang:yang-identifier;
mandatory true;
status deprecated;
description
"The YANG module name.";
}
leaf-list tag {
type tags:tag;
status deprecated;
description
"Tags associated with the module. See the IANA 'YANG
Module Tag Prefixes' registry for reserved prefixes and
the IANA 'IETF YANG Module Tags' registry for IETF tags.
revision 2020-02-29 { The contents of this list is constructed using the
description following steps:
"Initial revision.";
reference
"RFC XXXX: YANG Module Tags";
}
container module-tags-state { 1) System tags (i.e., tags of added by the system) are
config false; added.
status deprecated; 2) User-configured tags (i.e., tags added by
description configuration) are added.
"Contains the list of modules and their associated tags"; 3) Any tag that is equal to a masked-tag present in the
list module { corresponding ietf-module-tags:module-tags:module-tag leaf
key "name"; list for this module is removed.";
status deprecated; }
description }
"A list of modules and their associated tags"; }
leaf name { }
type yang:yang-identifier; <CODE ENDS>
mandatory true;
status deprecated;
description
"The YANG module name.";
}
leaf-list tag {
type tags:tag;
status deprecated;
description
"Tags associated with the module. See the IANA 'YANG Module
Tag Prefixes' registry for reserved prefixes and the IANA
'IETF YANG Module Tags' registry for IETF tags.
The contents of this list is constructed using the Figure 4: Non-NMDA Module Tags State Module
following steps:
1) System tags (i.e., tags of added by the system) are added. Acknowledgements
2) User configured tags (i.e., tags added by configuration)
are added.
3) Any tag that is equal to a masked-tag present in the
corresponding ietf-module-tags:module-tags:module-tag leaf
list for this module is removed.";
}
}
}
}
<CODE ENDS>
Figure 4: Non-NMDA Module Tags State Module Special thanks to Robert Wilton for his help improving the
introduction and providing the example use cases, as well as
generating the non-NMDA module.
Authors' Addresses Authors' Addresses
Christian Hopps Christian Hopps
LabN Consulting, L.L.C. LabN Consulting, L.L.C.
Email: chopps@chopps.org Email: chopps@chopps.org
Lou Berger Lou Berger
LabN Consulting, LLC. LabN Consulting, L.L.C.
Email: lberger@labn.net Email: lberger@labn.net
Dean Bogdanovic Dean Bogdanovic
Volta Networks Volta Networks
Email: ivandean@gmail.com Email: ivandean@gmail.com
 End of changes. 92 change blocks. 
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