<?xmlversion="1.0"?> <?xml-stylesheet type="text/xsl" href="rfc2629.xslt"?>version="1.0" encoding="UTF-8"?> <!DOCTYPE rfc SYSTEM'rfc2629.dtd'> <?rfc toc="yes"?> <?rfc compact="no"?> <?rfc subcompact="no"?> <?rfc symrefs="yes" ?> <?rfc sortrefs="yes"?> <?rfc iprnotified="no"?> <?rfc strict="yes"?>"rfc2629-xhtml.ent"> <rfc xmlns:xi="http://www.w3.org/2001/XInclude" ipr="trust200902" updates="8340" category="std" consensus="true" docName="draft-ietf-netmod-yang-data-ext-05">number="8791" obsoletes="" submissionType="IETF" xml:lang="en" tocInclude="true" symRefs="true" sortRefs="true" version="3"> <!-- xml2rfc v2v3 conversion 2.40.0 --> <front> <title abbrev="YANGStructure">YANGData Structure Extensions">YANG Data Structure Extensions</title> <seriesInfo name="RFC" value="8791"/> <author initials="A" surname="Bierman"fullname='Andy Bierman' >fullname="Andy Bierman"> <organization>YumaWorks</organization> <address> <email>andy@yumaworks.com</email> </address> </author> <author initials="M" surname="Bjorklund"fullname='Martin Bjorklund' >fullname="Martin Bjorklund"> <organization>Cisco</organization> <address><email>mbj@tail-f.com</email><email>mbj+ietf@4668.se</email> </address> </author> <author initials="K" surname="Watsen"fullname='Kent Watsen' >fullname="Kent Watsen"> <organization>Watsen Networks</organization> <address> <email>kent+ietf@watsen.net</email> </address> </author><date/><date year="2020" month="June" /> <abstract> <t> This document describes YANG mechanisms for defining abstract data structures with YANG. </t> </abstract> </front> <middle> <sectiontitle="Introduction" anchor="introduction">anchor="introduction" numbered="true" toc="default"> <name>Introduction</name> <t> There is a need for standard mechanisms to allow the definition of abstract data that is not intended to be implemented as configuration or operational state. The"yang‑data""yang-data" extension statement from RFC 8040 <xreftarget="RFC8040"/>target="RFC8040" format="default"/> was defined for thispurposepurpose, but it is limited in its functionality. </t> <t> The intended use of the"yang‑data""yang-data" extension was to model all or part of a protocol message, such as the"errors""errors" definition in the YANG module"ietf‑restconf""ietf-restconf" <xreftarget="RFC8040"/>,target="RFC8040" format="default"/>, or the contents of a file. However, protocols are often layered such that the header or payload portions of the message can be extended by external documents. The YANG statements that model a protocol need to support this extensibility that is already found in that protocol. </t> <t> This document defines a new YANG extension statement called"structure","structure", which is similar to but more flexible than the"yang‑data""yang-data" extension from <xreftarget="RFC8040"/>.target="RFC8040" format="default"/>. There is no assumption that a YANG data structure can only be used as a top-level abstraction, and it may also be nested within some other data structure. </t> <t> This document also defines a new YANG extension statement called"augment‑structure","augment&nbhy;structure", which allows abstract data structures to be augmented from externalmodules, similarlymodules and is similar to the existing YANG"augment""augment" statement. Note that"augment""augment" cannot be used to augment a YANG data structure since a YANG compiler or other tool is not required to understand the"structure""structure" extension. </t> <sectiontitle="Terminology" anchor="terminology">anchor="terminology" numbered="true" toc="default"> <name>Terminology</name> <t> The key words"MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY","<bcp14>MUST</bcp14>", "<bcp14>MUST NOT</bcp14>", "<bcp14>REQUIRED</bcp14>", "<bcp14>SHALL</bcp14>", "<bcp14>SHALL NOT</bcp14>", "<bcp14>SHOULD</bcp14>", "<bcp14>SHOULD NOT</bcp14>", "<bcp14>RECOMMENDED</bcp14>", "<bcp14>NOT RECOMMENDED</bcp14>", "<bcp14>MAY</bcp14>", and"OPTIONAL""<bcp14>OPTIONAL</bcp14>" in this document are to be interpreted as described in BCP 14 <xreftarget="RFC2119"/>target="RFC2119" format="default"/> <xreftarget="RFC8174"/>target="RFC8174" format="default"/> when, and only when, they appear in all capitals, as shown here. </t> <t> The followingterms areterm is used within this document: </t><t> <list style="symbols"> <t> YANG<dl newline="false" spacing="normal"> <dt>YANG datastructure: Astructure:</dt> <dd>A data structure defined with the"structure" statement. </t> </list> </t>"structure" statement.</dd> </dl> <sectiontitle="NMDA" anchor="nmda">anchor="nmda" numbered="true" toc="default"> <name>NMDA</name> <t> The following terms are defined in the Network Management Datastore Architecture (NMDA) <xreftarget="RFC8342"/>,target="RFC8342" format="default"/> and are not redefinedhere: </t> <t> <list style="symbols"> <t> configuration </t> <t> operational state </t> </list> </t>here:</t> <ul spacing="normal"> <li>configuration</li> <li>operational state</li> </ul> </section> <sectiontitle="YANG" anchor="yang"> <t> Theanchor="yang" numbered="true" toc="default"> <name>YANG</name> <t>The following terms are defined in <xreftarget="RFC7950"/>: </t> <t> <list style="symbols"> <t> absolute-schema-nodeid </t> <t> container </t> <t> datatarget="RFC7950" format="default"/> and are not redefined here:</t> <ul spacing="normal"> <li>absolute-schema-nodeid</li> <li>container</li> <li>data definitionstatement </t> <t> data node </t> <t> leaf </t> <t> leaf-list </t> <t> list </t> </list> </t>statement</li> <li>data node</li> <li>leaf</li> <li>leaf-list</li> <li>list</li> </ul> </section> </section> </section> <sectiontitle="Definitions" anchor="definitions">anchor="definitions" numbered="true" toc="default"> <name>Definitions</name> <t> A YANG data structure is defined with the"structure""structure" extension statement, which is defined in the YANG module"ietf‑yang‑structure‑ext"."ietf-yang-structure-ext". The argument to the"structure""structure" extension statement is the name of the data structure. The data structures are considered to be in the same identifier namespace as defined insection 6.2.1 of<xreftarget="RFC7950"/>.target="RFC7950" sectionFormat="of" section="6.2.1"/>. In particular, the seventh bullet7:states: </t><figure> <artwork><![CDATA[<blockquote> All leafs, leaf-lists, lists, containers, choices, rpcs, actions, notifications, anydatas, and anyxmls defined (directly or through a "uses" statement) within a parent node or at the top level of the module or its submodules share the same identifier namespace.]]></artwork> </figure></blockquote> <t> This means that data structures defined with the"structure""structure" statement cannot have the same name as sibling nodes from regular YANG data definition statements or other"structure""structure" statements in the same YANG module. </t> <t> This does not mean a YANG data structure, once defined, has to be used as a top-level protocol message or other top-level data structure. </t> <t> A YANG data structure is encoded in the same way as an"anydata""anydata" node. This means that the name of the structure is encoded as a"container","container", with the instantiated children encoded as child nodes to this node. For example, this structure: </t><figure> <artwork><![CDATA[<sourcecode type="yang"><![CDATA[ module example-errors { ... sx:structure my-error { leaf error-number { type int; } }} ]]></artwork> </figure>}]]> </sourcecode> <t> can be encoded in JSON as: </t><figure> <artwork><![CDATA[<sourcecode type="json"><![CDATA[ "example-errors:my-error": { "error-number": 131} ]]></artwork> </figure>}]]> </sourcecode> </section> <sectiontitle="YANGanchor="yang-data-structures-in-yang-tree-diagrams" numbered="true" toc="default"> <name>YANG Data Structures in YANG TreeDiagrams" anchor="yang-data-structures-in-yang-tree-diagrams">Diagrams</name> <t> A YANG data structure can be printed in a YANGTree Diagramtree diagram <xreftarget="RFC8340"/>.target="RFC8340" format="default"/>. This document updates RFC 8340 <xref target="RFC8340" format="default"/> by defining two new sections in the tree diagram for a module: </t><t> <list style="numbers"> <t> YANG<ol spacing="normal"> <li>YANG data structures, which are offset by two spaces and identified by the keyword"structure""structure" followed by the name of the YANG data structure and a colon(":")(":") character.</t> <t> YANG</li> <li>YANG data structure augmentations, which are offset by 2 spaces and identified by the keyword"augment‑structure""augment&nbhy;structure" followed by the augment target structure name and a colon(":") character. </t> </list> </t>(":") character.</li> </ol> <t> The new sections, including spacesconventions is:conventions, appear as follows: </t><figure> <artwork><![CDATA[<sourcecode type="yangtree"><![CDATA[ structure <structure-name>: +--<node> +--<node> | +--<node> +--<node> structure <structure-name>: +--<node> augment-structure <structure-name>: +--<node> +--<node> | +--<node> +--<node> augment-structure <structure-name>:+--<node> ]]></artwork> </figure>+--<node>]]> </sourcecode> <t> Nodes in YANG data structures are printed according to the rules defined insection 2.6 in<xreftarget="RFC8340"/>.target="RFC8340" sectionFormat="of" section="2.6"/>. The nodes in YANG data structures do not have any <flags>. </t> </section> <sectiontitle="YANGanchor="mod" numbered="true" toc="default"> <name>YANG Data Structure ExtensionsModule" anchor="mod"> <t> RFC Ed.: update the date below with the date of RFC publication and remove this note. </t> <t><CODE BEGINS> file "ietf-yang-structure-ext@2019-03-07.yang"</t> <figure> <artwork><![CDATA[Module</name> <sourcecode type="yang" name="ietf-yang-structure-ext@2020-06-08.yang" markers="true"><![CDATA[ module ietf-yang-structure-ext { yang-version 1.1; namespace "urn:ietf:params:xml:ns:yang:ietf-yang-structure-ext"; prefix sx; organization "IETF NETMOD (NETCONF Data Modeling Language) Working Group"; contact "WG Web:<http://tools.ietf.org/wg/netmod/><https://datatracker.ietf.org/wg/netmod/> WG List: <mailto:netmod@ietf.org> Author: Andy Bierman <mailto:andy@yumaworks.com> Author: Martin Bjorklund<mailto:mbj@tail-f.com><mailto:mbj+ietf@4668.se> Author: Kent Watsen <mailto:kent+ietf@watsen.net>"; description "This module contains conceptual YANG specifications for defining abstract data structures. The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'NOT RECOMMENDED', 'MAY', and 'OPTIONAL' in this document are to be interpreted as described in BCP 14 (RFC 2119) (RFC 8174) when, and only when, they appear in all capitals, as shown here. Copyright (c)20192020 IETF Trust and the persons identified as authors of the code. All rights reserved. Redistribution and use in source and binary forms, with or without modification, is permitted pursuant to, and subject 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). This version of this YANG module is part of RFCXXXX (https://www.rfc-editor.org/info/rfcXXXX);8791 (https://www.rfc-editor.org/info/rfc8791); see the RFC itself for full legal notices.";// RFC Ed.: update the date below with the date of RFC publication // and remove this note.revision2019-03-072020-06-08 { description "Initial revision.";// RFC Ed.: replace XXXX with RFC number and remove this notereference "RFCXXXX:8791: YANG Data Structure Extensions."; } extension structure { 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. Note that this extension does not define amedia-type.media type. A specification using this extension MUST specify the message encoding rules, including the content media type, if applicable. The mandatory 'name' parameter value identifies the YANG data structure that is being defined. This extension is only valid as a top-level statement, i.e., given as asub-statementsubstatement to 'module' or 'submodule'. Thesub-statementssubstatements of this extension MUST follow the ABNF rules below, where the rules are defined in RFC 7950: *must-stmt [status-stmt] [description-stmt] [reference-stmt] *(typedef-stmt / grouping-stmt) *data-def-stmt A YANG data structure defined with this extension statement is encoded in the same way as an 'anydata' node. This means that the name of the structure is encoded as a 'container', with the instantiated child statements encoded as child nodes to this node. The module name and namespace value for the YANG module using the extension statementisare assigned to each of the data definition statements resulting from the YANG data structure. The XPath document element is the extension statement itself, such that the child nodes of the document element are represented by the data-def-stmtsub-statementssubstatements within this extension. This conceptual document is the context for the following YANG statements: - must-stmt - when-stmt - path-stmt - min-elements-stmt - max-elements-stmt - mandatory-stmt - unique-stmt - ordered-by - instance-identifier data type The following data-def-stmtsub-statementssubstatements are constrained when used within a 'structure' extension statement. - The list-stmt is not required to have a key-stmt defined. - The config-stmt is ignored if present. "; } extension augment-structure { argument path { yin-element true; } description "This extension is used to specify an augmentation to a YANG data structure defined with the 'structure' 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 'augment-stmt'. Data definition statements within this statement specify the semantics and generic syntax for the additional data to be added to the specific YANG data structure, identified by the 'path' argument. The mandatory 'path' parameter value identifies the YANG conceptual data node that is beingaugmented,augmented and is represented as an absolute-schema-nodeid string, where the first node in the 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. This extension is only valid as a top-level statement, i.e., given as asub-statementsubstatement to 'module' or 'submodule'. Thesub-statementssubstatements of this extension MUST follow the ABNF rules below, where the rules are defined in RFC 7950: [status-stmt] [description-stmt] [reference-stmt] 1*(data-def-stmt / case-stmt) The module name and namespace value for the YANG module using the extension statementisare assigned to instance document data conforming to the data definition statements within this extension. 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-stmtsub-statementssubstatements within the augmented 'structure' statement. The context node of the 'augment-structure' statement is derived in the same way as the 'augment' statement, as defined insectionSection 6.4.1 of [RFC7950]. This conceptual node is considered the context node for the following YANG statements: - must-stmt - when-stmt - path-stmt - min-elements-stmt - max-elements-stmt - mandatory-stmt - unique-stmt - ordered-by - instance-identifier data type The following data-def-stmtsub-statementssubstatements are constrained when used within an 'augment-structure' extension statement. - The list-stmt is not required to have a key-stmt defined. - The config-stmt is ignored if present. 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; } } } "; }} ]]></artwork> </figure> <t><CODE ENDS></t>}]]> </sourcecode> </section> <sectiontitle="IANA Considerations" anchor="iana">anchor="iana" numbered="true" toc="default"> <name>IANA Considerations</name> <sectiontitle="YANGanchor="yang-module-registry" numbered="true" toc="default"> <name>YANG ModuleRegistry" anchor="yang-module-registry">Registry</name> <t>This document registers oneIANA has registered the following URIas a namespacein the"IETF"ns" subregistry within the "IETF XMLRegistry"Registry" <xreftarget="RFC3688"/>:target="RFC3688" format="default"/>: </t><figure> <artwork><![CDATA[ URI: urn:ietf:params:xml:ns:yang:ietf-yang-structure-ext Registrant<dl newline="false" spacing="compact" indent="6"> <dt>URI:</dt> <dd>urn:ietf:params:xml:ns:yang:ietf-yang-structure-ext</dd> <dt>Registrant Contact:The IESG. XML: N/A;</dt> <dd>The IESG.</dd> <dt>XML: </dt> <dd>N/A; the requested URI is an XMLnamespace. ]]></artwork> </figure>namespace.</dd> </dl> <t>This document registers oneIANA has registered the following YANG module in the"YANG"YANG ModuleNames" registryNames" subregistry <xreftarget="RFC6020"/>: </t> <figure> <artwork><![CDATA[ name: ietf-yang-structure-ext namespace: urn:ietf:params:xml:ns:yang:ietf-yang-structure-ext prefix: sx // RFC Ed.: replace XXXX with RFC number and remove this note reference: RFC XXXX ]]></artwork> </figure>target="RFC6020" format="default"/> within the "YANG Parameters" registry: </t> <dl newline="false" spacing="compact" indent="6"> <dt>Name:</dt> <dd>ietf-yang-structure-ext</dd> <dt>Namespace:</dt> <dd>urn:ietf:params:xml:ns:yang:ietf-yang-structure-ext</dd> <dt>Prefix:</dt> <dd>sx</dd> <dt>Reference:</dt> <dd>RFC 8791</dd> </dl> </section> </section> <sectiontitle="Security Considerations" anchor="security-considerations">anchor="security-considerations" numbered="true" toc="default"> <name>Security Considerations</name> <t> This document defines YANG extensions that are used to define conceptual YANG data structures. It does not introduce any new vulnerabilities beyond those specified in YANG 1.1 <xreftarget="RFC7950"/>. </t>target="RFC7950" format="default"/>.</t> </section> </middle> <back><references title="Normative References"><references> <name>References</name> <references> <name>Normative References</name> <xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.2119.xml"/> <xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.7950.xml"/> <xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.8040.xml"/> <xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.8174.xml"/> <xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.8340.xml"/> <xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.8342.xml"/> <referenceanchor="RFC2119" target="https://www.rfc-editor.org/info/rfc2119">anchor='W3C.REC-xml-20081126' target='http://www.w3.org/TR/2008/REC-xml-20081126'> <front><title>Key words for use in RFCs to Indicate Requirement Levels</title><title>Extensible Markup Language (XML) 1.0 (Fifth Edition)</title> <author initials='T.' surname='Bray' fullname='Tim Bray'> <organization /> </author> <author initials='J.' surname='Paoli' fullname='Jean Paoli'> <organization /> </author> <author initials='M.' surname='Sperberg-McQueen' fullname='Michael Sperberg-McQueen'> <organization /> </author> <author initials='E.' surname='Maler' fullname='Eve Maler'> <organization /> </author> <authorinitials="S." surname="Bradner" fullname="S. Bradner"> <organization/>initials='F.' surname='Yergeau' fullname='François Yergeau'> <organization /> </author> <dateyear="1997" month="March"/> <abstract> <t>In many standards track documents several words are used to signify the requirements in the specification. These words are often capitalized. This document defines these words as they should be interpreted in IETF documents. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements.</t> </abstract>month='November' year='2008' /> </front> <seriesInfoname="BCP" value="14"/> <seriesInfo name="RFC" value="2119"/> <seriesInfo name="DOI" value="10.17487/RFC2119"/>name='World Wide Web Consortium Recommendation' value='REC-xml-20081126' /> <format type='HTML' target='http://www.w3.org/TR/2008/REC-xml-20081126' /> </reference><reference anchor="RFC7950" target="https://www.rfc-editor.org/info/rfc7950"> <front> <title>The YANG 1.1 Data Modeling Language</title> <author initials="M." surname="Bjorklund" fullname="M. Bjorklund" role="editor"> <organization/> </author> <date year="2016" month="August"/> <abstract> <t>YANG is a data modeling language used to model configuration data, state data, Remote Procedure Calls, and notifications for network management protocols. This document describes the syntax and semantics of version 1.1 of the YANG language. YANG version 1.1 is a maintenance release of the YANG language, addressing ambiguities and defects in the original specification. There are a small number of backward incompatibilities from YANG version 1. This document also specifies the YANG mappings to the Network Configuration Protocol (NETCONF).</t> </abstract> </front> <seriesInfo name="RFC" value="7950"/> <seriesInfo name="DOI" value="10.17487/RFC7950"/> </reference> <reference anchor="RFC8040" target="https://www.rfc-editor.org/info/rfc8040"> <front> <title>RESTCONF Protocol</title> <author initials="A." surname="Bierman" fullname="A. Bierman"> <organization/> </author> <author initials="M." surname="Bjorklund" fullname="M. Bjorklund"> <organization/> </author> <author initials="K." surname="Watsen" fullname="K. Watsen"> <organization/> </author> <date year="2017" month="January"/> <abstract> <t>This document describes an HTTP-based protocol that provides a programmatic interface for accessing data defined in YANG, using the datastore concepts defined in the Network Configuration Protocol (NETCONF).</t> </abstract> </front> <seriesInfo name="RFC" value="8040"/> <seriesInfo name="DOI" value="10.17487/RFC8040"/> </reference> <reference anchor="RFC8174" target="https://www.rfc-editor.org/info/rfc8174"> <front> <title>Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words</title> <author initials="B." surname="Leiba" fullname="B. Leiba"> <organization/> </author> <date year="2017" month="May"/> <abstract> <t>RFC 2119 specifies common key words that may be used in protocol specifications. This document aims to reduce the ambiguity by clarifying that only UPPERCASE usage of the key words have the defined special meanings.</t> </abstract> </front> <seriesInfo name="BCP" value="14"/> <seriesInfo name="RFC" value="8174"/> <seriesInfo name="DOI" value="10.17487/RFC8174"/> </reference> <reference anchor="RFC8340" target="https://www.rfc-editor.org/info/rfc8340"> <front> <title>YANG Tree Diagrams</title> <author initials="M." surname="Bjorklund" fullname="M. Bjorklund"> <organization/> </author> <author initials="L." surname="Berger" fullname="L. Berger" role="editor"> <organization/> </author> <date year="2018" month="March"/> <abstract> <t>This document captures the current syntax used in YANG module tree diagrams. The purpose of this document is to provide a single location for this definition. This syntax may be updated from time to time based on the evolution of the YANG language.</t> </abstract> </front> <seriesInfo name="BCP" value="215"/> <seriesInfo name="RFC" value="8340"/> <seriesInfo name="DOI" value="10.17487/RFC8340"/> </reference> <reference anchor="RFC8342" target="https://www.rfc-editor.org/info/rfc8342"> <front> <title>Network Management Datastore Architecture (NMDA)</title> <author initials="M." surname="Bjorklund" fullname="M. Bjorklund"> <organization/> </author> <author initials="J." surname="Schoenwaelder" fullname="J. Schoenwaelder"> <organization/> </author> <author initials="P." surname="Shafer" fullname="P. Shafer"> <organization/> </author> <author initials="K." surname="Watsen" fullname="K. Watsen"> <organization/> </author> <author initials="R." surname="Wilton" fullname="R. Wilton"> <organization/> </author> <date year="2018" month="March"/> <abstract> <t>Datastores are a fundamental concept binding the data models written in the YANG data modeling language to network management protocols such as the Network Configuration Protocol (NETCONF) and RESTCONF. This document defines an architectural framework for datastores based on the experience gained with the initial simpler model, addressing requirements that were not well supported in the initial model. This document updates RFC 7950.</t> </abstract> </front> <seriesInfo name="RFC" value="8342"/> <seriesInfo name="DOI" value="10.17487/RFC8342"/> </reference> </references> <references title="Informative References"> <reference anchor="RFC3688" target="https://www.rfc-editor.org/info/rfc3688"> <front> <title>The IETF XML Registry</title> <author initials="M." surname="Mealling" fullname="M. Mealling"> <organization/> </author> <date year="2004" month="January"/> <abstract> <t>This document describes an IANA maintained registry for IETF standards which use Extensible Markup Language (XML) related items such as Namespaces, Document Type Declarations (DTDs), Schemas, and Resource Description Framework (RDF) Schemas.</t> </abstract> </front> <seriesInfo name="BCP" value="81"/> <seriesInfo name="RFC" value="3688"/> <seriesInfo name="DOI" value="10.17487/RFC3688"/> </reference> <reference anchor="RFC6020" target="https://www.rfc-editor.org/info/rfc6020"> <front> <title>YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)</title> <author initials="M." surname="Bjorklund" fullname="M. Bjorklund" role="editor"> <organization/> </author> <date year="2010" month="October"/> <abstract> <t>YANG is a data modeling language used to model configuration and state data manipulated by the Network Configuration Protocol (NETCONF), NETCONF remote procedure calls, and NETCONF notifications. [STANDARDS-TRACK]</t> </abstract> </front> <seriesInfo name="RFC" value="6020"/> <seriesInfo name="DOI" value="10.17487/RFC6020"/> </reference> </references> <section title="Examples" anchor="examples"> <section title=""structure" Example" anchor="structure-example"> <t></references> <references> <name>Informative References</name> <xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.3688.xml"/> <xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.6020.xml"/> </references> </references> <section anchor="examples" numbered="true" toc="default"> <name>Examples</name> <section anchor="structure-example" numbered="true" toc="default"> <name>"structure" Example</name> <t> This example shows a simple address book that could be stored as anartifact.artifact: </t><figure> <artwork><![CDATA[<sourcecode type="yang"><![CDATA[ module example-module { yang-version 1.1; namespace "urn:example:example-module"; prefix exm; 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"; } } }} ]]></artwork> </figure>}]]> </sourcecode> <t> Below is the tree diagram of thismodule.module: </t><figure> <artwork><![CDATA[<sourcecode type="yangtree"><![CDATA[ module: example-module structure address-book: +-- address* [last first] +-- last string +-- first string +-- street? string +-- city? string +-- state?string ]]></artwork> </figure>string]]> </sourcecode> </section> <sectiontitle=""augment‑structure" Example" anchor="augment-structure-example">anchor="augment-structure-example" numbered="true" toc="default"> <name>"augment&nbhy;structure" Example</name> <t> This example adds"county""county" and"zipcode""zipcode" leafs to the address book: </t><figure> <artwork><![CDATA[<sourcecode type="yang"><![CDATA[ module example-module-aug { yang-version 1.1; namespace "urn:example:example-module-aug"; prefix exma; import ietf-yang-structure-ext { prefix sx; } 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"; } }} ]]></artwork> </figure>}]]> </sourcecode> <t> Below is the tree diagram of thismodule.module: </t><figure> <artwork><![CDATA[<sourcecode type="yangtree"><![CDATA[ module: example-module-aug augment-structure /exm:address-book/exm:address: +-- county? string +-- zipcode?string ]]></artwork> </figure>string]]> </sourcecode> </section> <sectiontitle="XMLanchor="xml-encoding-example" numbered="true" toc="default"> <name>XML EncodingExample" anchor="xml-encoding-example">Example</name> <t> This example shows how an address book can be encoded inXML:XML <xref target="W3C.REC-xml-20081126"/>: </t><figure> <artwork><![CDATA[<sourcecode type="xml"><![CDATA[ <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> <last>Root</last> <first>Charlie</first> <street>4711 Cobblestone Way</street> <city>Bedrock</city> <zipcode xmlns="urn:example:example-module-aug">70777</zipcode> </address></address-book> ]]></artwork> </figure></address-book>]]> </sourcecode> </section> <sectiontitle="JSONanchor="json-encoding-example" numbered="true" toc="default"> <name>JSON EncodingExample" anchor="json-encoding-example">Example</name> <t> This example shows how an address book can be encoded in JSON: </t><figure> <artwork><![CDATA[<sourcecode type="json"><![CDATA[ "example-module:address-book": { "address": [ { "city": "Bedrock", "example-module-aug:zipcode": "70777", "first": "Fred", "last": "Flintstone", "street": "301 Cobblestone Way" }, { "city": "Bedrock", "example-module-aug:zipcode": "70777", "first": "Charlie", "last": "Root", "street": "4711 Cobblestone Way" } ]} ]]></artwork> </figure>}]]> </sourcecode> </section> <sectiontitle=""structure" example that definesanchor="structure-example-that-defines-a-non-top-level-structure" numbered="true" toc="default"> <name>"structure" Example That Defines anon-top-level structure" anchor="structure-example-that-defines-a-non-top-level-structure">Non-top-level Structure</name> <t> The following example defines a data structure with errorinformation,information that can be included in an<error‑info><error&nbhy;info> element in an<rpc‑error>.<rpc&nbhy;error>: </t><figure> <artwork><![CDATA[<sourcecode type="yang"><![CDATA[ module example-error-info { yang-version 1.1; namespace "urn:example:example-error-info"; prefix exei; import ietf-yang-structure-ext { prefix sx; } sx:structure my-example-error-info { leaf error-code { type uint32; } }} ]]></artwork> </figure>}]]> </sourcecode> <t> The example below shows how this structure can be used in an<rpc‑error>.<rpc&nbhy;error>: </t><figure> <artwork><![CDATA[<sourcecode type="xml"><![CDATA[ <rpc-reply message-id="101" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0"> <rpc-error> <error-type>protocol</error-type> <error-tag>operation-failed</error-tag> <error-severity>error</error-severity> <error-info> <my-example-error-info xmlns="urn:example:example-error-info"> <error-code>42</error-code> </my-example-error-info> </error-info> </rpc-error></rpc-reply> ]]></artwork> </figure></rpc-reply>]]> </sourcecode> </section> </section></back></rfc></back> </rfc>