draft-ietf-netmod-yang-data-ext-01.txt		draft-ietf-netmod-yang-data-ext-02.txt
	Network Working Group A. Bierman		Network Working Group A. Bierman
	Internet-Draft YumaWorks		Internet-Draft YumaWorks
	Intended status: Standards Track M. Bjorklund		Intended status: Standards Track M. Bjorklund
	Expires: September 6, 2018 Tail-f Systems		Expires: September 9, 2019 Cisco
	K. Watsen		K. Watsen
	Juniper Networks		Watsen Networks
	March 5, 2018		March 8, 2019
	YANG Data Extensions		YANG Data Structure Extensions
	draft-ietf-netmod-yang-data-ext-01		draft-ietf-netmod-yang-data-ext-02
	Abstract		Abstract
	This document describes YANG mechanisms for defining abstract data		This document describes YANG mechanisms for defining abstract data
	structures with YANG. It is intended to replace and extend the		structures with YANG. It is intended to replace and extend the
	"yang-data" extension statement defined in RFC 8040.		"yang-data" extension statement defined in RFC 8040.
	Status of This Memo		Status of This Memo
	This Internet-Draft is submitted in full conformance with the		This Internet-Draft is submitted in full conformance with the
	skipping to change at page 1, line 35 ¶		skipping to change at page 1, line 35 ¶
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF). Note that other groups may also distribute		Task Force (IETF). Note that other groups may also distribute
	working documents as Internet-Drafts. The list of current Internet-		working documents as Internet-Drafts. The list of current Internet-
	Drafts is at http://datatracker.ietf.org/drafts/current/.		Drafts is at http://datatracker.ietf.org/drafts/current/.
	Internet-Drafts are draft documents valid for a maximum of six months		Internet-Drafts are draft documents valid for a maximum of six months
	and may be updated, replaced, or obsoleted by other documents at any		and may be updated, replaced, or obsoleted by other documents at any
	time. It is inappropriate to use Internet-Drafts as reference		time. It is inappropriate to use Internet-Drafts as reference
	material or to cite them other than as "work in progress."		material or to cite them other than as "work in progress."
	This Internet-Draft will expire on September 6, 2018.		This Internet-Draft will expire on September 9, 2019.
	Copyright Notice		Copyright Notice
	Copyright (c) 2018 IETF Trust and the persons identified as the		Copyright (c) 2019 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 . . . . . . . . . . . . . . . . . . . . . . . . 2		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
	1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3		1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
	1.1.1. NMDA . . . . . . . . . . . . . . . . . . . . . . . . 3		1.1.1. NMDA . . . . . . . . . . . . . . . . . . . . . . . . 3
	1.1.2. YANG . . . . . . . . . . . . . . . . . . . . . . . . 3		1.1.2. YANG . . . . . . . . . . . . . . . . . . . . . . . . 3
	2. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 4		2. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 4
	2.1. Restrictions on Conceptual YANG Data . . . . . . . . . . 4		3. YANG Data Structure Extensions Module . . . . . . . . . . . . 4
	2.2. YANG Data Extensions Module . . . . . . . . . . . . . . . 4		4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
	3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9		4.1. YANG Module Registry . . . . . . . . . . . . . . . . . . 9
	3.1. YANG Module Registry . . . . . . . . . . . . . . . . . . 9		5. Security Considerations . . . . . . . . . . . . . . . . . . . 9
	4. Security Considerations . . . . . . . . . . . . . . . . . . . 9		6. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
	5. Normative References . . . . . . . . . . . . . . . . . . . . 9		6.1. Normative References . . . . . . . . . . . . . . . . . . 9
			6.2. Informative References . . . . . . . . . . . . . . . . . 10
	Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 10		Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 10
	A.1. yang-data Example . . . . . . . . . . . . . . . . . . . . 10		A.1. "structure" Example . . . . . . . . . . . . . . . . . . . 10
	A.2. augment-yang-data Example . . . . . . . . . . . . . . . . 10		A.2. "augment-structure" Example . . . . . . . . . . . . . . . 11
	Appendix B. Change Log . . . . . . . . . . . . . . . . . . . . . 11		A.3. XML Encoding Example . . . . . . . . . . . . . . . . . . 12
	B.1. v00 to v01 . . . . . . . . . . . . . . . . . . . . . . . 11		A.4. JSON Encoding Example . . . . . . . . . . . . . . . . . . 12
	Appendix C. Open Issues . . . . . . . . . . . . . . . . . . . . 11		Appendix B. Change Log . . . . . . . . . . . . . . . . . . . . . 13
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11		B.1. v01 to v02 . . . . . . . . . . . . . . . . . . . . . . . 13
			B.2. v00 to v01 . . . . . . . . . . . . . . . . . . . . . . . 13
			Appendix C. Open Issues . . . . . . . . . . . . . . . . . . . . 13
			Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13
	1. Introduction		1. Introduction
	There is a need for standard mechanisms to allow the definition of		There is a need for standard mechanisms to allow the definition of
	abstract data that is not intended to be implemented as configuration		abstract data that is not intended to be implemented as configuration
	or operational state. The "yang-data" extension statement from RFC		or operational state. The "yang-data" extension statement from RFC
	8040 [RFC8040] is defined for this purpose, however it is limited in		8040 [RFC8040] was defined for this purpose but it is limited in its
	its functionality.		functionality.
	The intended use of the "yang-data" extension is to model all or part		The intended use of the "yang-data" extension was to model all or
	of a protocol message, such as the "errors" definition in ietf-		part of a protocol message, such as the "errors" definition in the
	restconf.yang [RFC8040], or the contents of a file. However,		YANG module "ietf-restconf" [RFC8040], or the contents of a file.
	protocols are often layered such that the header or payload portions		However, protocols are often layered such that the header or payload
	of the message can be extended by external documents. The YANG		portions of the message can be extended by external documents. The
	statements that model a protocol need to support this extensibility		YANG statements that model a protocol need to support this
	that is already found in that protocol.		extensibility that is already found in that protocol.
	This document defines a new YANG extension statement called		The "yang-data" extension from [RFC8040] has been copied here,
	"augment-yang-data", which allows abstract data structures to be		renamed to "structure", and updated to be more flexible. There is no
			assumption that a YANG data structure can only be used as a top-level
			abstraction, instead of nested within some other data structure.
			This document also defines a new YANG extension statement called
			"augment-structure", which allows abstract data structures to be
	augmented from external modules, similar to the existing YANG		augmented from external modules, similar to the existing YANG
	"augment" statement. Note that "augment" cannot be used to augment a		"augment" statement. Note that "augment" cannot be used to augment a
	yang data structure since a YANG compiler or other tool is not		YANG data structure since a YANG compiler or other tool is not
	required to understand the "yang-data" extension.		required to understand the "structure" extension.
	The "yang-data" extension from [RFC8040] has been copied here and
	updated to be more flexible. There is no longer a requirement for
	the "yang-data" statement to result in exactly one container object.
	There is no longer an assumption that a yang data structure can only
	be used as a top-level abstraction, instead of nested within some
	other data structure.
	1.1. Terminology		1.1. Terminology
	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", "NOT RECOMMENDED", "MAY", and
	document are to be interpreted as described in [RFC2119].		"OPTIONAL" in this document are to be interpreted as described in BCP
			14 [RFC2119] [RFC8174] when, and only when, they appear in all
			capitals, as shown here.
	The following terms are used within this document:		The following terms are used within this document:
	o yang data structure: A data structure defined with the "yang-data"		o YANG data structure: A data structure defined with the "structure"
	statement.		statement.
	1.1.1. NMDA		1.1.1. NMDA
	The following terms are defined in the Network Management Datastore		The following terms are defined in the Network Management Datastore
	Architecture (NMDA) [I-D.ietf-netmod-revised-datastores]. and are		Architecture (NMDA) [RFC8342]. and are not redefined here:
	not redefined here:
	o configuration		o configuration
	o operational state		o operational state
	1.1.2. YANG		1.1.2. YANG
	The following terms are defined in [RFC7950]:		The following terms are defined in [RFC7950]:
	o absolute-schema-nodeid		o absolute-schema-nodeid
	skipping to change at page 4, line 7 ¶		skipping to change at page 4, line 7 ¶
	o data node		o data node
	o leaf		o leaf
	o leaf-list		o leaf-list
	o list		o list
	2. Definitions		2. Definitions
	2.1. Restrictions on Conceptual YANG Data		A YANG Data Structure is defined with the "structure" extension
			statement, defined in the YANG module "ietf-yang-structure-ext". The
	This document places restrictions on the "yang-data" external		argument to the "structure" extension statement is the name of the
	statements that can be used with the "yang-data" and		data structure. The data structures are considered to be in the same
	"augment-yang-data" extensions. The conceptual data definitions are		identifier namespace as defined in section 6.2.1 of [RFC7950]. In
	considered to be in the same identifier namespace as defined in		particular, bullet 7:
	section 6.2.1 of [RFC7950]. In particular, bullet 7:
	All leafs, leaf-lists, lists, containers, choices, rpcs, actions,		All leafs, leaf-lists, lists, containers, choices, rpcs, actions,
	notifications, anydatas, and anyxmls defined (directly or through		notifications, anydatas, and anyxmls defined (directly or through
	a "uses" statement) within a parent node or at the top level of		a "uses" statement) within a parent node or at the top level of
	the module or its submodules share the same identifier namespace.		the module or its submodules share the same identifier namespace.
	This means that conceptual data defined with the "yang-data" or		This means that data structures defined with the "structure"
	"augment-yang-data" statements cannot have the same local-name as		statement cannot have the same name as sibling nodes from regular
	sibling nodes from regular YANG data definition statements or other		YANG data definition statements or other "structure" statements in
	"yang-data" or "augment-yang-data" statements.		the same YANG module.
	This does not mean a yang data structure has to be used as a top-
	level protocol message or other top-level data structure. A yang
	data structure does not have to result in a single container.
	2.2. YANG Data Extensions Module		This does not mean a YANG data structure has to be used as a top-
			level protocol message or other top-level data structure.
	The "ietf-yang-data-ext" module defines the "augment-yang-data"		3. YANG Data Structure Extensions Module
	extension to augment conceptual data already defined with the
	"yang-data" extension. The RESTCONF "yang-data" extension has been
	moved to this document and updated.
	RFC Ed.: update the date below with the date of RFC publication and		RFC Ed.: update the date below with the date of RFC publication and
	remove this note.		remove this note.
	<CODE BEGINS> file "ietf-yang-data-ext@2018-03-05.yang"		<CODE BEGINS> file "ietf-yang-structure-ext@2019-03-07.yang"
	module ietf-yang-data-ext {		module ietf-yang-structure-ext {
	yang-version 1.1;		yang-version 1.1;
	namespace "urn:ietf:params:xml:ns:yang:ietf-yang-data-ext";		namespace "urn:ietf:params:xml:ns:yang:ietf-yang-structure-ext";
	prefix "yd";		prefix sx;
	organization		organization
	"IETF NETMOD (NETCONF Data Modeling Language) Working Group";		"IETF NETMOD (NETCONF Data Modeling Language) Working Group";
			contact
			"WG Web: <http://tools.ietf.org/wg/netmod/>
			WG List: <mailto:netmod@ietf.org>
	contact		Author: Andy Bierman
	"WG Web: <http://tools.ietf.org/wg/netmod/>		<mailto:andy@yumaworks.com>
	WG List: <mailto:netmod@ietf.org>
	Author: Andy Bierman
	<mailto:andy@yumaworks.com>
	Author: Martin Bjorklund		Author: Martin Bjorklund
	<mailto:mbj@tail-f.com>		<mailto:mbj@tail-f.com>
	Author: Kent Watsen		Author: Kent Watsen
	<mailto:kwatsen@juniper.net>";		<mailto:kent+ietf@watsen.net>";
	description		description
	"This module contains conceptual YANG specifications		"This module contains conceptual YANG specifications for defining
	for defining abstract 'yang-data' data structures.		abstract data structures.
	Copyright (c) 2017 - 2018 IETF Trust and the persons identified		The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL
	as authors of the code. All rights reserved.		NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED',
			'MAY', and 'OPTIONAL' in this document are to be interpreted as
			described in BCP 14 (RFC 2119) (RFC 8174) when, and only when,
			they appear in all capitals, as shown here.
	Redistribution and use in source and binary forms, with or		Copyright (c) 2019 IETF Trust and the persons identified
	without modification, is permitted pursuant to, and subject		as authors of the code. All rights reserved.
	to the license terms contained in, the Simplified BSD License
	set forth in Section 4.c of the IETF Trust's Legal Provisions
	Relating to IETF Documents
	(http://trustee.ietf.org/license-info).";
	revision 2018-03-05 {		Redistribution and use in source and binary forms, with or
	description		without modification, is permitted pursuant to, and subject
	"Initial revision.";		to the license terms contained in, the Simplified BSD License
	reference		set forth in Section 4.c of the IETF Trust's Legal Provisions
	// RFC Ed.: replace XXXX with RFC number and remove this note		Relating to IETF Documents
	"RFC XXXX: YANG Data Extensions.";		(http://trustee.ietf.org/license-info).";
	}
	extension yang-data {		// RFC Ed.: update the date below with the date of RFC publication
	argument name {		// and remove this note.
	yin-element true;
	}
	description
	"This extension is used to specify a YANG data template which
	represents conceptual data defined in YANG. It is
	intended to describe hierarchical data independent of
	protocol context or specific message encoding format.
	Data definition statements within a yang-data extension
	specify the generic syntax for the specific YANG data
	template, whose name is the argument of the yang-data
	extension statement.
	Note that this extension does not define a media-type.		revision 2019-03-07 {
			description
			"Initial revision.";
			// RFC Ed.: replace XXXX with RFC number and remove this note
			reference
			"RFC XXXX: YANG Structure Extensions.";
			}
	A specification using this extension MUST specify the		extension structure {
	message encoding rules, including the content media type.		argument name {
			yin-element true;
			}
			description
			"This extension is used to specify a YANG data structure that
			represents conceptual data defined in YANG. It is intended to
			describe hierarchical data independent of protocol context or
			specific message encoding format. Data definition statements
			within a 'structure' extension statement specify the generic
			syntax for the specific YANG data structure, whose name is the
			argument of the 'structure' extension statement.
	The mandatory 'name' parameter value identifies the YANG		Note that this extension does not define a media-type. A
	data template that is being defined. It contains the		specification using this extension MUST specify the message
	template name. This parameter is only used for readability		encoding rules, including the content media type, if
	purposes. There are no mechanisms to reuse yang-data by		applicable.
	its template name value.
	This extension is ignored unless it appears as a top-level		The mandatory 'name' parameter value identifies the YANG data
	statement. It MUST contain data definition statements		structure that is being defined.
	that result in a set of data definition statements.
	If the yang data template is intended to be used as		This extension is only valid as a top-level statement, i.e.,
	a top-level structure, then the yang data template needs to		given as a sub-statement to 'module' or 'submodule'.
	result in a single container, so an instance of the YANG data
	template can thus be translated into an XML instance document,
	whose top-level element corresponds to the top-level container.
	The module name and namespace value for the YANG module using		The sub-statements of this extension MUST follow the ABNF
	the extension statement is assigned to each of the data		rules below, where the rules are defined in RFC 7950:
	definition statements resulting from the yang data template.
	The name of each data definition statement resulting from
	a yang data template is assigned to a top-level identifier name
	in the data node identifier namespace, according to RFC 7950,
	section 6.2.1.
	The sub-statements of this extension MUST follow the		*must-stmt
	'data-def-stmt' rule in the YANG ABNF.		[status-stmt]
			[description-stmt]
			[reference-stmt]
			*(typedef-stmt / grouping-stmt)
			*data-def-stmt
	The XPath document root is the extension statement itself,		A YANG data structure defined with this extension statement is
	such that the child nodes of the document root are		encoded in the same way as an 'anydata' statement. This means
	represented by the data-def-stmt sub-statements within		that the name of the structure is encoded as a 'container',
	this extension. This conceptual document is the context		with the instantiated child statements encoded as child nodes
	for the following YANG statements:		to this node.
	- must-stmt		The module name and namespace value for the YANG module using
	- when-stmt		the extension statement is assigned to each of the data
	- path-stmt		definition statements resulting from the YANG data structure.
	- min-elements-stmt
	- max-elements-stmt
	- mandatory-stmt
	- unique-stmt
	- ordered-by
	- instance-identifier data type
	The following data-def-stmt sub-statements are constrained		The XPath document element is the extension statement itself,
	when used within a yang-data-resource extension statement.		such that the child nodes of the document element are
			represented by the data-def-stmt sub-statements within this
			extension. This conceptual document is the context for the
			following YANG statements:
	- The list-stmt is not required to have a key-stmt defined.		- must-stmt
	- The if-feature-stmt is ignored if present.		- when-stmt
	- The config-stmt is ignored if present.		- path-stmt
	- The available identity values for any 'identityref'		- min-elements-stmt
	leaf or leaf-list nodes is limited to the module		- max-elements-stmt
	containing this extension statement, and the modules		- mandatory-stmt
	imported into that module.		- unique-stmt
	";		- ordered-by
	}		- instance-identifier data type
	extension augment-yang-data {		The following data-def-stmt sub-statements are constrained
	argument path {		when used within a 'structure' extension statement.
	yin-element true;
	}
	description
	"This extension is used to specify an augmentation to
	conceptual data defined with the 'yang-data' statement.
	It is intended to describe hierarchical data independent
	of protocol context or specific message encoding format.
	This statement has almost the same structure as the		- The list-stmt is not required to have a key-stmt defined.
	'augment-stmt'. Data definition statements within this		- The config-stmt is ignored if present.
	statement specify the semantics and generic syntax for the		";
	additional data to be added to the specific YANG data template,
	identified by the 'path' argument.
	The mandatory 'path' parameter value identifies the YANG		}
	conceptual data node that is being augmented, represented
	as an absolute-schema-nodeid string.
	This extension is ignored unless it appears as a top-level		extension augment-structure {
	statement. The sub-statements of this extension MUST follow		argument path {
	the 'data-def-stmt' rule in the YANG ABNF.		yin-element true;
			}
			description
			"This extension is used to specify an augmentation to YANG data
			structure defined with the 'structure' statement. It is
			intended to describe hierarchical data independent of protocol
			context or specific message encoding format.
	The module name and namespace value for the YANG module using		This statement has almost the same structure as the
	the extension statement is assigned to instance document data		'augment-stmt'. Data definition statements within this
	conforming to the data definition statements within		statement specify the semantics and generic syntax for the
	this extension.		additional data to be added to the specific YANG data
			structure, identified by the 'path' argument.
	The XPath document root is the augmented extension statement		The mandatory 'path' parameter value identifies the YANG
	itself, such that the child nodes of the document root are		conceptual data node that is being augmented, represented as
	represented by the data-def-stmt sub-statements within		an absolute-schema-nodeid string, where the first node in the
	the augmented yang-data statement.		absolute-schema-nodeid string identifies the YANG data
			structure to augment, and the rest of the nodes in the string
			identifies the node within the YANG structure to augment.
	The context node of the augment-yang-data statement is derived		This extension is only valid as a top-level statement, i.e.,
	in the same way as the 'augment' statement, as defined in		given as a sub-statement to 'module' or 'submodule'.
	section 6.4.1 of [RFC7950]. This conceptual node is
	considered the context node for the following YANG statements:
	- must-stmt		The sub-statements of this extension MUST follow the ABNF
	- when-stmt		rules below, where the rules are defined in RFC 7950:
	- path-stmt
	- min-elements-stmt
	- max-elements-stmt
	- mandatory-stmt
	- unique-stmt
	- ordered-by
	- instance-identifier data type
	The following data-def-stmt sub-statements are constrained		[status-stmt]
	when used within a augment-yang-data extension statement.		[description-stmt]
			[reference-stmt]
			1*(data-def-stmt / case-stmt)
	- The list-stmt is not required to have a key-stmt defined.		The module name and namespace value for the YANG module using
	- The if-feature-stmt is ignored if present.		the extension statement is assigned to instance document data
	- The config-stmt is ignored if present.		conforming to the data definition statements within this
	- The available identity values for any 'identityref'		extension.
	leaf or leaf-list nodes is limited to the module
	containing this extension statement, and the modules
	imported into that module.
	Example:		The XPath document element is the augmented extension
			statement itself, such that the child nodes of the document
			element are represented by the data-def-stmt sub-statements
			within the augmented 'structure' statement.
	foo.yang {		The context node of the 'augment-structure' statement is
	import yang-data-ext { prefix yd; }		derived in the same way as the 'augment' statement, as defined
			in section 6.4.1 of [RFC7950]. This conceptual node is
			considered the context node for the following YANG statements:
	yd:yang-data foo-data {		- must-stmt
	container foo-con { }		- when-stmt
	}		- path-stmt
	}		- min-elements-stmt
			- max-elements-stmt
			- mandatory-stmt
			- unique-stmt
			- ordered-by
			- instance-identifier data type
	bar.yang {		The following data-def-stmt sub-statements are constrained
	import yang-data-ext { prefix yd; }		when used within an 'augment-structure' extension statement.
	import foo { prefix foo; }
	yd:augment-yang-data /foo:foo-con {		- The list-stmt is not required to have a key-stmt defined.
	leaf add-leaf1 { type int32; }		- The config-stmt is ignored if present.
	leaf add-leaf2 { type string; }
	}
	}
	";
	}
	}		Example:
			module foo {
			import ietf-yang-structure-ext { prefix sx; }
			sx:structure foo-data {
			container foo-con { }
			}
			}
			module bar {
			import ietf-yang-structure-ext { prefix sx; }
			import foo { prefix foo; }
			sx:augment-structure /foo:foo-data/foo:foo-con {
			leaf add-leaf1 { type int32; }
			leaf add-leaf2 { type string; }
			}
			}
			";
			}
			}
	<CODE ENDS>		<CODE ENDS>
	3. IANA Considerations		4. IANA Considerations
	3.1. YANG Module Registry		4.1. YANG Module Registry
	This document registers one URI as a namespace in the "IETF XML		This document registers one URI as a namespace in the "IETF XML
	Registry" [RFC3688]:		Registry" [RFC3688]:
	URI: urn:ietf:params:xml:ns:yang:ietf-yang-data-ext		URI: urn:ietf:params:xml:ns:yang:ietf-yang-structure-ext
	Registrant Contact: The IESG.		Registrant Contact: The IESG.
	XML: N/A; the requested URI is an XML namespace.		XML: N/A; the requested URI is an XML namespace.
	This document registers one YANG module in the "YANG Module Names"		This document registers one YANG module in the "YANG Module Names"
	registry [RFC6020]:		registry [RFC6020]:
	name: ietf-yang-data-ext		name: ietf-yang-structure-ext
	namespace: urn:ietf:params:xml:ns:yang:ietf-yang-data-ext		namespace: urn:ietf:params:xml:ns:yang:ietf-yang-structure-ext
	prefix: yd		prefix: sx
	// RFC Ed.: replace XXXX with RFC number and remove this note		// RFC Ed.: replace XXXX with RFC number and remove this note
	reference: RFC XXXX		reference: RFC XXXX
	4. Security Considerations		5. Security Considerations
	This document defines YANG extensions that are used to define		This document defines YANG extensions that are used to define
	conceptual YANG data. It does not introduce any new vulnerabilities		conceptual YANG data structures. It does not introduce any new
	beyond those specified in YANG 1.1 [RFC7950].		vulnerabilities beyond those specified in YANG 1.1 [RFC7950].
	5. Normative References		6. References
	[I-D.ietf-netmod-revised-datastores]		6.1. Normative References
	Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
	and R. Wilton, "Network Management Datastore
	Architecture", draft-ietf-netmod-revised-datastores-10
	(work in progress), January 2018.
	[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, March 1997.		Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/
			RFC2119, March 1997, <https://www.rfc-editor.org/info/
	[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,		rfc2119>.
	January 2004.
	[RFC6020] Bjorklund, M., "YANG - A Data Modeling Language for the
	Network Configuration Protocol (NETCONF)", RFC 6020,
	October 2010.
	[RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",		[RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
	RFC 7950, DOI 10.17487/RFC7950, August 2016,		RFC 7950, DOI 10.17487/RFC7950, August 2016,
	<http://www.rfc-editor.org/info/rfc7950>.		<https://www.rfc-editor.org/info/rfc7950>.
	[RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF		[RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
	Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,		Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
	<http://www.rfc-editor.org/info/rfc8040>.		<https://www.rfc-editor.org/info/rfc8040>.
			[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
			2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
			May 2017, <https://www.rfc-editor.org/info/rfc8174>.
			[RFC8342] Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
			and R. Wilton, "Network Management Datastore Architecture
			(NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018,
			<https://www.rfc-editor.org/info/rfc8342>.
			6.2. Informative References
			[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
			DOI 10.17487/RFC3688, January 2004, <https://www.rfc-
			editor.org/info/rfc3688>.
			[RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for
			the Network Configuration Protocol (NETCONF)", RFC 6020,
			DOI 10.17487/RFC6020, October 2010, <https://www.rfc-
			editor.org/info/rfc6020>.
	Appendix A. Examples		Appendix A. Examples
	A.1. yang-data Example		A.1. "structure" Example
	This example shows a simple address book that could be stored as an		This example shows a simple address book that could be stored as an
	artifact.		artifact.
	yd:yang-data example-address-book {		module example-module {
	container address-book {		yang-version 1.1;
	list address {		namespace "urn:example:example-module";
	key "last first";		prefix exm;
	leaf last {
	type string;
	description "Last name";
	}
	leaf first {
	type string;
	description "First name";
	}
	leaf street {
	type string;
	description "Street name";
	}
	leaf city {
	type string;
	description "City name";
	}
	leaf state {
	type string;
	description "State name";
	}
	}
	}
	}
	A.2. augment-yang-data Example		import ietf-yang-structure-ext {
			prefix sx;
			}
			sx:structure address-book {
			list address {
			key "last first";
			leaf last {
			type string;
			description "Last name";
			}
			leaf first {
			type string;
			description "First name";
			}
			leaf street {
			type string;
			description "Street name";
			}
			leaf city {
			type string;
			description "City name";
			}
			leaf state {
			type string;
			description "State name";
			}
			}
			}
			}
			A.2. "augment-structure" Example
	This example adds "county" and "zipcode" leafs to the address book:		This example adds "county" and "zipcode" leafs to the address book:
	yd:augment-yang-data /address-book/address {		module example-module-aug {
	leaf county {		yang-version 1.1;
	type string;		namespace "urn:example:example-module-aug";
	description "County name";		prefix exma;
	}
	leaf zipcode {		import ietf-yang-structure-ext {
	type string;		prefix sx;
	description "Postal zipcode";		}
	}		import example-module {
	}		prefix exm;
			}
			sx:augment-structure "/exm:address-book/exm:address" {
			leaf county {
			type string;
			description "County name";
			}
			leaf zipcode {
			type string;
			description "Postal zipcode";
			}
			}
			}
			A.3. XML Encoding Example
			This example shows how an address book can be encoded in XML:
			<address-book xmlns="urn:example:example-module">
			<address>
			<last>Flintstone</last>
			<first>Fred</first>
			<street>301 Cobblestone Way</street>
			<city>Bedrock</city>
			<zipcode xmlns="urn:example:example-module-aug">70777</zipcode>
			</address>
			</address-book>
			A.4. JSON Encoding Example
			This example shows how an address book can be encoded in JSON:
			"example-module:address-book": {
			"address": [
			{
			"city": "Bedrock",
			"example-module-aug:zipcode": "70777",
			"first": "Fred",
			"last": "Flintstone",
			"street": "301 Cobblestone Way"
			}
			]
			}
	Appendix B. Change Log		Appendix B. Change Log
	B.1. v00 to v01		RFC Ed.: remove this section before publication.
			B.1. v01 to v02
			o terminology fixes (use the term "structure" instead of "template")
			o renamed the statement to "structure" from "yang-data"
			o removed limitations on if-feature and identities in YANG
			structures
			B.2. v00 to v01
	o moved open issues to github		o moved open issues to github
	o added examples section		o added examples section
	o filled in IANA considerations		o filled in IANA considerations
	Appendix C. Open Issues		Appendix C. Open Issues
	The YANG Data Extensions issues are tracked on github.com:		RFC Ed.: remove this section before publication.
			The YANG Data Structure Extensions issues are tracked on github.com:
	https://github.com/netmod-wg/yang-data-ext/issues		https://github.com/netmod-wg/yang-data-ext/issues
	Authors' Addresses		Authors' Addresses
	Andy Bierman		Andy Bierman
	YumaWorks		YumaWorks
	Email: andy@yumaworks.com		Email: andy@yumaworks.com
	Martin Bjorklund		Martin Bjorklund
	Tail-f Systems		Cisco
	Email: mbj@tail-f.com		Email: mbj@tail-f.com
	Kent Watsen		Kent Watsen
	Juniper Networks		Watsen Networks
	Email: kwatsen@juniper.net		Email: kent+ietf@watsen.net
End of changes. 77 change blocks.
	302 lines changed or deleted		379 lines changed or added
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