| Internet-Draft | YANG Schema Comparison | October 2026 |
| Vaško, et al. | Expires 25 April 2027 | [Page] |
This document specifies an algorithm with two input variants for comparing revisions of a YANG schema to determine the scope of changes and produce a list of the changes between the revisions. The output of the algorithm can be used to help select an appropriate YANG semantic version number for a new YANG Module revision. It also specifies a YANG module for YANG-structured output of these algorithms, that can be easily consumed in a machine-readable way.¶
This Internet-Draft is submitted in full conformance with the 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 and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress."¶
This Internet-Draft will expire on 25 April 2027.¶
Copyright (c) 2026 IETF Trust and the persons identified as the document authors. All rights reserved.¶
This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Revised BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Revised BSD License.¶
This document defines a common algorithm for comparing two revisions of a YANG schema. As input, there can be two types of YANG schema representations: single locally resolved YANG modules or fully resolved set of YANG modules (on-the-wire schema). The algorithm output for each of these representations serves a different purpose. It can help YANG authors with assigning the correct semantic version of a module based on [I-D.ietf-netmod-yang-semver] or tools processing YANG instance data can use it to learn about the exact data changes, respectively.¶
The algorithm operates in a straightforward way traversing all the statements and their substatements in both the old and new module representations collecting identified changes. These are then reported in a concise output with information about the overall backwards compatibility between the two modules. Exact output format is out of scope for this document but Appendix A includes an example of a YANG module whose YANG data can represent all the possible changes and so a complete output of this algorithm.¶
Every change is classified as editorial, backwards-compatible, or non-backwards-compatible. This conformance is decided based on rules found in other documents, specifically [RFC7950], [I-D.ietf-netmod-yang-module-versioning], and [I-D.ietf-netmod-yang-semver]. For older YANG 1.0 modules, the rules in [RFC6020] apply instead.¶
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 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.¶
This document makes use of the following terminology introduced in the YANG 1.1 Data Modeling Language [RFC7950]:¶
In addition, this document uses the following terminology:¶
The YANG language defines several statements that act as syntactic abstraction and need to be processed before a YANG module can be used for handling YANG instance data. For example, a “uses” statement is replaced by all the substatements of a referenced “grouping” statement or a “typedef” statement can be linked to other “type” statements. The referenced statements can be local (defined in the same module, or included submodule) but also foreign (defined in another imported module).¶
This representation of a YANG module includes all submodules of the main module but resolves only statements that reference other statements found in the same module. No references to imported modules (that are using an imported prefix) are resolved.¶
For example, any changes of a referenced “typedef” or “grouping” defined in an imported module would not affect the locally resolved module and are out of scope for this representation.¶
All the rules for classifying individual statement changes mentioned in Section 4.2 apply to this module representation.¶
Regardless of whether the “deviation” target node is local in the same module or in an imported module, it is never resolved and applied. Instead, the “deviation” statement with all its substatements is kept in the locally resolved module so that it can be considered in the schema comparison algorithm.¶
The “refine” statement is processed differently based on whether the affected “grouping” is defined in an imported module or the local YANG module. In the former case, when the relevant grouping is imported, the “refine” is not resolved and kept in the module. And then examined in the comparison algorithm, similarly to the “deviation” statement.¶
However, all the “refine” statements targeting a local “grouping” are applied on the nodes of the grouping when the “uses” is resolved. After processing the “refine” statements with all its substatements, they are effectively removed from the locally resolved module to avoid reporting changes of any “refine” statements twice.¶
The fully resolved schema representation consists of one or more YANG modules. Each of these is fully resolved according to the rules of the YANG language meaning that every referenced statement, including to other imported modules, is resolved, unlike locally resolved modules. The result is one large tree with schema nodes of all the YANG modules. The comparison algorithm MAY then choose to compare top-level schema node subtrees belonging only to a single YANG module.¶
Next, all the statements used only for syntactic abstraction that do not affect YANG instance data are removed. Note that the “description” or “units” statements are kept because they may influence the data. Also, “error-app-tag” and “error-message” statements remain in the fully resolved schema for applications to learn that the generated error information has changed.¶
The steps taken when fully resolving a module include:¶
After the resolution, the following statements are completely removed with their substatements:¶
Also, these schema nodes are removed but replaced with their schema node substatements:¶
The term “schema” was chosen instead of “module” on purpose because when statements are imported from external modules, the resulting schema then includes statements from several YANG modules. But the fully resolved schema representation of a module always includes only the top-level schema node trees of that module.¶
Only a subset of the module update rules in Section 4.2 apply for the fully resolved schema. Specifically, the rules for removed statements cannot be applied but other present statements are processed normally.¶
How the concrete set of YANG modules of a fully resolved schema is described is out of scope of this document. But suitable existing structures include YANG data of “ietf-yang-library” from [RFC8525] or “ietf-yang-package-instance” in [I-D.ietf-netmod-yang-packages].¶
Selecting a suitable schema representation for the comparison algorithm depends on the desired purpose. But for a complete set of changes, both the representations should be compared and their output merged to get the combined output of the two comparisons.¶
YANG module authors will primarily be interested in the locally resolved module representation. Using it for the comparison algorithm will yield all the changes that occurred in the specific YANG module only while ignoring any possible changes in imported modules. This information can then directly be used to decide the correct semantic version of the new revision of this module. The rules for selecting versions are defined in [I-D.ietf-netmod-yang-semver].¶
Any YANG-based application handling YANG instance data always uses the fully resolved schema representation. So, when running the schema comparison algorithm with the intent of learning the changes in the corresponding valid YANG instance data of the module, this representation should be used. With some additional information, the output of this comparison can then also be used to transform valid data of the old schema revision to data valid for the new schema revision. All these tools and applications are typically clients or servers of YANG-driven protocols, e.g. NETCONF, RESTCONF, or gRPC.¶
To illustrate the different output of the comparison algorithm each schema representation can generate for the same YANG module changes, following are a few examples.¶
When a “typedef” or “grouping” name changes, the algorithm for locally resolved module will detect the change and report it as non-backwards-compatible. This is useful especially when importing such a module to learn that any references to the original statements will no longer be valid. However, if using the fully resolved schema, this difference will not be detected at all since it does not affect YANG instance data corresponding to this module.¶
Another specific use-case is when a module with “uses” that referenced an external “grouping” replaces that “uses” node directly with schema nodes in the “grouping” effectively resolving the “uses” similarly to a YANG module parser. Such a change is non-backwards-compatible based on the YANG 1.1 updating rules and reported that way when using a locally resolved module. But the fully resolved schemas will be completely the same before and after the change so the comparison algorithm will not generate any changes and report full compatibility of the old and the new modules with their instance data.¶
This algorithm is defined for individual locally resolved modules and fully resolved schemas. All the statements are compared with their content, recursively, in the old revision and the new revision of the module or schema. Depth-first search order for the statement traversal SHOULD be used.¶
The non data definition statements are considered modified when their content is changed or any of their substatements are changed. If a statement is present in the old revision and missing in the new revision, it is considered removed. Conversely, if missing in the old revision but present in the new revision, it is considered added.¶
Data definition statements are compared similarly except that a change in a descendant data definition statement is not considered a change of the parent data definition statement but a separate change instead.¶
Only statements with any changes are reported and included in the comparison algorithm output.¶
When generating the comparison output of two modules, unique identification of these modules SHOULD be included. For both the old and the new revision of the base module, its name, revision, list of submodules, and a leaf-list of enabled features is included. For the fully resolved schema, the same information is also reported for all the imported YANG modules, recursively. This ensures that if any other output is produced with a different set of changes for two fully resolved schemas, their identification information must also differ.¶
Every change is classified as editorial, backwards-compatible, or non-backwards-compatible. The classification is based on Section 11 of [RFC7950] which mentions most of the possible changes between two revisions of a YANG 1.1 module and Section 3.1 of [I-D.ietf-netmod-yang-module-versioning] adds more details about the exact conformance of statements with various "status" statement values. Finally, [I-D.ietf-netmod-yang-semver] defines what classifies as an editorial change.¶
General non-normative explanation of change conformance classification can be found in Appendix B.¶
All the statement change conformance follows the general rules above if these statements are present in the schema representation, see Section 3. But this clarification is added to make certain that the rules are interpreted correctly.¶
Since “deviation” and “refine” statements are not among the allowed statements that can be changed when updating a module in Section 11 of [RFC7950], any non-editorial change of these statements or their substatements is treated as non-backwards-compatible.¶
But since “augment” statements can only add schema nodes, these can be processed and compared normally.¶
So, for example, even if removing the “mandatory” statement is considered backwards-compatible, a new “deviation” removing the “mandatory” statement from its target node is considered a non-backwards-compatible change. Similarly a “refine” of the “description” of a node is classified as non-backward-compatible change. However, a change in the “description” of a “deviation” statement is treated as a standard “description” change because it describes the “deviation” statement itself and does not affect the deviation target node.¶
There are cases when it may be impossible for tooling to accurately determine the conformance of a change but a default conformance is always assumed for every statement. The affected ambiguous statements with their default conformances are:¶
Normally, any modification of these statements is reported with the default change conformance. However, if the author of the new revision of a YANG module determines that the change of one of the aforementioned statements has a different conformance based on the compatibility rules for the specific statement, they can decide to use the special extension instances to signify this fact. These are:¶
They determine the conformance of the change of the marked statement to be editorial, backwards-compatible, or non-backwards-compatible, respectively. The argument is a semantic version of the YANG module revision that introduced the specific change and these extension instances are sticky, meaning they remain in the module even in its later revisions. Also, a YANG statement can have multiple conformance extension statements. For example, when a pattern changes in multiple versions of a module, each change can be marked with an extension to explicitly state the conformance of the change.¶
Tools implementing schema comparison SHOULD support comparing locally resolved modules, fully resolved schemas, and both representations together. In case the comparison generates YANG data for the "ietf-yang-schema-comparison-output" YANG module, simple XPath filters can be used to select any subset of changes.¶
Data definition statements are present in both the locally resolved module and fully resolved schema. So if both representations are compared normally, there would be duplicate changes reported in the algorithm output. These duplicate changes MUST be avoided and filtered out.¶
YANG module with extensions for fine-tuning the classification of differences between two revisions of YANG schemas.¶
<CODE BEGINS> file "ietf-yang-schema-comparison@2026-09-02.yang"
module ietf-yang-schema-comparison {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-yang-schema-comparison";
prefix yscmp;
organization
"IETF NETMOD (Network Modeling) Working Group";
contact
"WG List: NETMOD WG list <mailto:netmod@ietf.org>
WG Web: https://datatracker.ietf.org/wg/netmod
Author: Michal Vaško
<mailto:mvasko@cesnet.cz>
Author: Rob Wilton
<mailto:rwilton@cisco.com>
Author: Per Andersson
<mailto:per.ietf@ionio.se>";
description
"This YANG 1.1 module contains extensions to support comparison
between different versions of YANG schemas.
Copyright (c) 2026 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 Revised
BSD License set forth in Section 4.c of the IETF Trust's
Legal Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC XXXX
(https://www.rfc-editor.org/info/rfcXXXX); see the RFC
itself for full legal notices.
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.";
// RFC Ed.: update the date below with the date of RFC publication
// and remove this note.
// RFC Ed.: replace XXXX (inc above) with actual RFC number and
// remove this note.
revision 2026-09-02 {
description
"Initial revision.";
reference
"RFC XXXX: YANG Schema Comparison";
}
extension ed-change-at {
argument semver;
description
"Marks statements in a new revision of a module
that introduces an editorial change of the statement.
The argument marks the most recent version of the
module where the statement has been changed.
Can only be a substatement of 'pattern', 'when',
'must', 'description', 'reference', 'presence', or
extension instance statements.";
reference
"RFC 7950: The YANG 1.1 Data Modeling Language, section 11;
RFC 6020: YANG - A Data Modeling Language for the Network
Configuration Protocol (NETCONF), section 10";
}
extension bc-change-at {
argument semver;
description
"Marks statements in a new revision of a module
that introduces a backwards-compatible change of
the statement.
The argument marks the most recent version of the
module where the statement has been changed.
Can only be a substatement of 'pattern', 'when',
'must', 'description', 'reference', 'presence', or
extension instance statements.";
reference
"RFC 7950: The YANG 1.1 Data Modeling Language, section 11;
RFC 6020: YANG - A Data Modeling Language for the Network
Configuration Protocol (NETCONF), section 10";
}
extension nbc-change-at {
argument semver;
description
"Marks statements in a new revision of a module
that introduces a non-backwards-compatible change of
the statement.
The argument marks the most recent version of the
module where the statement has been changed.
Can only be a substatement of 'pattern', 'when',
'must', 'description', 'reference', 'presence', or
extension instance statements.";
reference
"RFC 7950: The YANG 1.1 Data Modeling Language, section 11;
RFC 6020: YANG - A Data Modeling Language for the Network
Configuration Protocol (NETCONF), section 10";
}
}
<CODE ENDS>¶
This document grew out of the YANG module versioning design team that was formed after IETF 101. The following individuals are (or have been) members of the design team and have contributed on the YANG versioning project:¶
The idea of a tooling-based comparison of YANG module revisions was first described in [I-D.clacla-netmod-yang-model-update]. This document builds on those initial ideas.¶
This section is modeled after the template described in Section 3.7.1 of [RFC9907].¶
The YANG modules specified in this document define extensions ("ietf-yang-schema-comparison") and a schema for data ("ietf-yang-schema-comparison-output") that are designed to be used by offline tooling to generate output describing the differences between two supplied YANG modules.¶
The YANG module specified in this document MAY be accessed via network management protocols such as NETCONF [RFC6241] or RESTCONF [RFC8040]. The lowest NETCONF layer is the secure transport layer, and the mandatory-to-implement secure transport is Secure Shell (SSH) [RFC6242]. The lowest RESTCONF layer is HTTPS, and the mandatory-to-implement secure transport is TLS [RFC8446].¶
The Network Configuration Access Control Model (NACM) [RFC8341] provides the means to restrict access for particular NETCONF or RESTCONF users to a preconfigured subset of all available NETCONF or RESTCONF protocol operations and content.¶
When the module is used by offline tooling, there are no security considerations, since the user has full access to all YANG modules being used.¶
The "schema-comparison" structure defined in the "ietf-yang-schema-comparison-output" module contains all the groupings reflecting the changes between YANG modules. If instances of this structure are generated or published by online tooling, care needs to be taken so that information about non-public YANG modules is not inadvertently disclosed.¶
Since the module does not define any RPCs, actions, or notifications, the security considerations for such statements are not provided here.¶
This document registers two URIs in the "ns" subregistry of the IETF XML Registry [RFC3688] maintained at https://www.iana.org/assignments/xml-registry/xml-registry.xhtml#ns. Following the format defined in [RFC3688], the following registrations are requested:¶
URI: urn:ietf:params:xml:ns:yang:ietf-yang-schema-comparison Registrant Contact: The IESG. XML: N/A, the requested URI is an XML namespace. URI: urn:ietf:params:xml:ns:yang:ietf-yang-schema-comparison-output Registrant Contact: The IESG. XML: N/A, the requested URI is an XML namespace.¶
This document registers two YANG modules in the YANG Module Names registry [RFC6020] maintained at https://www.iana.org/assignments/yang-parameters/yang-paramaters.xhtml. Following the format defined in [RFC6020], the following registrations are requested:¶
Name: ietf-yang-schema-comparison XML Namespace: urn:ietf:params:xml:ns:yang:ietf-yang-schema-comparison Prefix: schema-cmp Reference: RFC XXXX Name: ietf-yang-schema-comparison-output XML Namespace: urn:ietf:params:xml:ns:yang:ietf-yang-schema-comparison-output Prefix: schema-cmp-out Reference: RFC XXXX¶
This YANG module defines the specific output of the schema comparison algorithm, supporting comparison of the locally resolved module, fully resolved schema, or both. The "ietf-yang-schema-comparison-output" YANG module imports definitions from the "ietf-yang-types" module defined in [RFC6991], the "ietf-yang-library" module defined in [RFC8525], and the "ietf-yang-structure-ext" module defined in [RFC8791].¶
Generating schema comparison data in the form of YANG instance data compliant with this YANG module is optional but makes it easier for further automatic processing by tools and also allows for simple filtering of the data.¶
Non data definition statements are uniquely identified with their YANG identifier and data definition statements with their absolute schema node-ids. For every change, the changed statement and the parent of the changed statement are included. While redundant in many cases, it allows the algorithm to uniquely report changes in nested statements, e.g. an extension instance change in the type of a leaf statement. Also, all the unchanged substatements with their value or content are included for every changed statement, for both the older and the newer revision of the YANG module, if applicable. This ensures that the output includes all the possibly required information without relying on learning it from the YANG modules themselves.¶
<CODE BEGINS> file "ietf-yang-schema-comparison-output@2026-09-02.yang"
module ietf-yang-schema-comparison-output {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-yang-schema-comparison-output";
prefix yscmp-out;
import ietf-yang-types {
prefix yang;
reference
"RFC 6991: Common YANG Data types";
}
import ietf-yang-library {
prefix yanglib;
reference
"RFC 8525: YANG Library";
}
import ietf-yang-structure-ext {
prefix sx;
reference
"RFC 8791: YANG Data Structure Extensions";
}
import ietf-yang-semver {
prefix ysv;
reference
"RFC XXXX: YANG Semantic Versioning";
}
organization
"IETF NETMOD (Network Modeling) Working Group";
contact
"WG List: NETMOD WG list <mailto:netmod@ietf.org>
WG Web: https://datatracker.ietf.org/wg/netmod
Author: Michal Vaško
<mailto:mvasko@cesnet.cz>
Author: Rob Wilton
<mailto:rwilton@cisco.com>
Author: Per Andersson
<mailto:per.ietf@ionio.se>";
description
"This YANG 1.1 module contains definitions of output of comparison
between different versions of YANG schemas. The base schema nodes
describe changes in a compiled YANG module with all of its
included submodules and imported modules. The rest of the schema
nodes are optional and describe changes in all the statements of a
single YANG module.
Copyright (c) 2026 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 Revised
BSD License set forth in Section 4.c of the IETF Trust's
Legal Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC XXXX
(https://www.rfc-editor.org/info/rfcXXXX); see the RFC
itself for full legal notices.
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.";
// RFC Ed.: update the date below with the date of RFC publication
// and remove this note.
// RFC Ed.: replace XXXX (inc above) with actual RFC number and
// remove this note.
revision 2026-09-02 {
description
"Initial revision.";
reference
"RFC XXXX: YANG Schema Comparison";
}
typedef schema-node-path {
type string;
description
"Node schema path (node-id). A generic type is used to not enforce
their evaluation or validation in this context.";
}
typedef schema-stmt-path {
type string;
description
"Path to a statement. Any non data node parents are encoded
specially.";
}
typedef stmt-type {
type enumeration {
enum base {
description
"YANG statement 'base'.";
}
enum bit {
description
"YANG statement 'bit'.";
}
enum config {
description
"YANG statement 'config'.";
}
enum contact {
description
"YANG statement 'contact'.";
}
enum default {
description
"YANG statement 'default'.";
}
enum description {
description
"YANG statement 'description'.";
}
enum enum {
description
"YANG statement 'enum'.";
}
enum error-app-tag {
description
"YANG statement 'error-app-tag'.";
}
enum error-message {
description
"YANG statement 'error-message'.";
}
enum extension {
description
"YANG statement 'extension'.";
}
enum extension-instance {
description
"Any extension instance YANG statement.";
}
enum feature {
description
"YANG statement 'feature'.";
}
enum fraction-digits {
description
"YANG statement 'fraction-digits'.";
}
enum identity {
description
"YANG statement 'identity'.";
}
enum if-feature {
description
"YANG statement 'if-feature'.";
}
enum import {
description
"YANG statement 'import'.";
}
enum include {
description
"YANG statement 'include'.";
}
enum length {
description
"YANG statement 'length'.";
}
enum mandatory {
description
"YANG statement 'mandatory'.";
}
enum max-elements {
description
"YANG statement 'max-elements'.";
}
enum min-elements {
description
"YANG statement 'min-elements'.";
}
enum must {
description
"YANG statement 'must'.";
}
enum node {
description
"YANG statement 'container', 'leaf', 'leaf-list', 'list',
'anydata', 'anyxml', 'rpc', 'action', or 'notification'.
If the locally resolved module is also compared, it can
additionally be 'choice', 'case', 'input', 'output',
'uses', 'augment', or 'grouping'.";
}
enum ordered-by {
description
"YANG statement 'ordered-by'.";
}
enum organization {
description
"YANG statement 'organization'.";
}
enum path {
description
"YANG statement 'path'.";
}
enum pattern {
description
"YANG statement 'pattern'.";
}
enum prefix {
description
"YANG statement 'prefix'.";
}
enum presence {
description
"YANG statement 'presence'.";
}
enum range {
description
"YANG statement 'range'.";
}
enum reference {
description
"YANG statement 'reference'.";
}
enum refine {
description
"YANG statement 'refine'.";
}
enum require-instance {
description
"YANG statement 'require-instance'.";
}
enum revision-date {
description
"YANG statement 'revision-date'.";
}
enum status {
description
"YANG statement 'status'.";
}
enum type {
description
"YANG statement 'type'.";
}
enum typedef {
description
"YANG statement 'typedef'.";
}
enum units {
description
"YANG statement 'units'.";
}
enum unique {
description
"YANG statement 'unique'.";
}
enum when {
description
"YANG statement 'when'.";
}
enum yang-version {
description
"YANG statement 'yang-version'.";
}
}
description
"Type of the statement that a change affects.";
}
typedef revision-or-empty {
type union {
type empty;
type yanglib:revision-identifier;
}
description
"Module or submodule revision. If it has none, an empty value is used.";
}
grouping if-feature-stmts {
description
"Describes changes of all the if-features on a statement.";
leaf-list if-feature {
type string;
description
"Value of an if-feature statement.";
}
}
grouping ext-instance-stmt {
description
"Describes changes of an extension instance.";
leaf module {
type yang:yang-identifier;
mandatory true;
description
"Module with the extension definition of an extension
instance.";
}
leaf name {
type yang:yang-identifier;
mandatory true;
description
"Name of the extension definition of an extension instance.";
}
leaf argument {
type string;
description
"Argument used of an extension definition.";
}
anydata substatements {
description
"Any substatements of the extension instance.";
}
}
grouping ext-instance-stmts {
description
"Describes changes of all the extension instances.";
list ext-instance {
description
"List of extension-instance substatements.";
uses ext-instance-stmt;
}
}
grouping status-stmt {
description
"Describes a status statement change.";
leaf status {
type enumeration {
enum current {
description
"Current effective status of a statement.";
}
enum deprecated {
description
"Deprecated effective status of a statement.";
}
enum obsolete {
description
"Obsolete effective status of a statement.";
}
}
mandatory true;
description
"Status substatement value.";
}
}
grouping must-stmts {
description
"Describes changes of all the must statements of a specific parent
statement.";
list must {
description
"List of must substatements.";
leaf condition {
type string;
description
"Condition substatement value.";
}
uses restriction-substmts;
}
}
grouping when-stmts {
description
"Describes changes of all the when statements of a specific parent
statement.";
list when {
description
"List of when substatements.";
leaf condition {
type string;
description
"Condition substatement value.";
}
leaf description {
type string;
description
"Description substatement value.";
}
leaf reference {
type string;
description
"Reference substatement value.";
}
uses status-stmt;
uses ext-instance-stmts;
}
}
grouping restriction-substmts {
description
"Common substatements shared by all restriction statements.";
leaf description {
type string;
description
"Description substatement value.";
}
leaf reference {
type string;
description
"Reference substatement value.";
}
leaf error-message {
type string;
description
"Error-message substatement value.";
}
leaf error-app-tag {
type string;
description
"Error-app-tag substatement value.";
}
uses ext-instance-stmts;
}
grouping type-substmts {
description
"Describes a type statement change.";
leaf base-type {
type enumeration {
enum int8 {
description
"YANG built-in type 'int8'.";
}
enum int16 {
description
"YANG built-in type 'int16'.";
}
enum int32 {
description
"YANG built-in type 'int32'.";
}
enum int64 {
description
"YANG built-in type 'int64'.";
}
enum uint8 {
description
"YANG built-in type 'uint8'.";
}
enum uint16 {
description
"YANG built-in type 'uint16'.";
}
enum uint32 {
description
"YANG built-in type 'uint32'.";
}
enum uint64 {
description
"YANG built-in type 'uint64'.";
}
enum decimal64 {
description
"YANG built-in type 'decimal64'.";
}
enum string {
description
"YANG built-in type 'string'.";
}
enum boolean {
description
"YANG built-in type 'boolean'.";
}
enum enumeration {
description
"YANG built-in type 'enumeration'.";
}
enum bits {
description
"YANG built-in type 'bits'.";
}
enum binary {
description
"YANG built-in type 'binary'.";
}
enum leafref {
description
"YANG built-in type 'leafref'.";
}
enum identityref {
description
"YANG built-in type 'identityref'.";
}
enum empty {
description
"YANG built-in type 'empty'.";
}
enum union {
description
"YANG built-in type 'union'.";
}
enum instance-identifier {
description
"YANG built-in type 'instance-identifier'.";
}
}
description
"Type substatement value.";
}
container range {
description
"Range statement substatements.";
list interval {
description
"Intervals of a range statement.";
leaf min {
type int64;
description
"Lower boundary of an interval of a range statement.";
}
leaf max {
type int64;
description
"Upper boundary of an interval of a range statement.";
}
}
uses restriction-substmts;
}
container length {
description
"Length statement substatements.";
list interval {
description
"Intervals of a length statement.";
leaf min {
type uint64;
description
"Lower boundary of an interval of a length statement.";
}
leaf max {
type uint64;
description
"Upper boundary of an interval of a length statement.";
}
}
uses restriction-substmts;
}
leaf fraction-digits {
type uint8;
description
"Fraction-digits substatement value.";
}
list pattern {
description
"List of pattern statements.";
leaf expression {
type string;
description
"Pattern substatement value.";
}
leaf inverted {
type boolean;
description
"A value of true indicates that the pattern's 'modifier'
substatement is 'invert-match'.";
reference
"RFC 7950 Section 9.4.6";
}
uses restriction-substmts;
}
list enum {
key "name";
ordered-by user;
description
"List of enum statements. Keeps the same order of the statements
as in the module.";
leaf name {
type yang:yang-identifier;
description
"Enum statement name.";
}
uses if-feature-stmts {
description
"Populated only for locally resolved module.";
}
leaf description {
type string;
description
"Description substatement value.";
}
leaf reference {
type string;
description
"Reference substatement value.";
}
leaf value {
type int32;
description
"Value substatement value.";
}
uses status-stmt;
uses ext-instance-stmts;
}
list bit {
key "name";
ordered-by user;
description
"List of bit statements. Keeps the same order of the statements
as in the module.";
leaf name {
type yang:yang-identifier;
description
"Bit statement name.";
}
uses if-feature-stmts {
description
"Populated only for locally resolved module.";
}
leaf description {
type string;
description
"Description substatement value.";
}
leaf reference {
type string;
description
"Reference substatement value.";
}
leaf position {
type uint32;
description
"Position substatement value.";
}
uses status-stmt;
uses ext-instance-stmts;
}
leaf path {
type string;
description
"Path substatement value.";
}
leaf require-instance {
type boolean;
description
"Require-instance substatement value.";
}
leaf-list base {
type yang:yang-identifier;
description
"List of base substatement values.";
}
uses ext-instance-stmts;
}
grouping type-local-substmts {
description
"Describes a locally resolved module type statement change.";
leaf name {
type yang:yang-identifier;
description
"Type argument substatement value.";
}
container range {
description
"Range statement substatements.";
leaf restriction {
type string;
description
"Range argument substatement value.";
}
uses restriction-substmts;
}
container length {
description
"Length statement substatements.";
leaf restriction {
type string;
description
"Length argument substatement value.";
}
uses restriction-substmts;
}
leaf fraction-digits {
type uint8;
description
"Fraction-digits substatement value.";
}
list pattern {
description
"List of pattern statements.";
leaf expression {
type string;
description
"Pattern substatement value.";
}
leaf inverted {
type empty;
description
"Presence indicates that the pattern's 'modifier'
substatement is 'invert-match'.";
reference
"RFC 7950 Section 9.4.6";
}
uses restriction-substmts;
}
list enum {
key "name";
ordered-by user;
description
"List of enum statements. Keeps the same order of the statements
as in the module.";
leaf name {
type yang:yang-identifier;
description
"Enum statement name.";
}
uses if-feature-stmts;
leaf description {
type string;
description
"Description substatement value.";
}
leaf reference {
type string;
description
"Reference substatement value.";
}
leaf value {
type int32;
description
"Value substatement value.";
}
uses status-stmt;
uses ext-instance-stmts;
}
list bit {
key "name";
ordered-by user;
description
"List of bit statements. Keeps the same order of the statements
as in the module.";
leaf name {
type yang:yang-identifier;
description
"Bit statement name.";
}
uses if-feature-stmts;
leaf description {
type string;
description
"Description substatement value.";
}
leaf reference {
type string;
description
"Reference substatement value.";
}
leaf position {
type uint32;
description
"Position substatement value.";
}
uses status-stmt;
uses ext-instance-stmts;
}
leaf path {
type string;
description
"Path substatement value.";
}
leaf require-instance {
type boolean;
description
"Require-instance substatement value.";
}
leaf-list base {
type yang:yang-identifier;
description
"List of base substatement values.";
}
uses ext-instance-stmts;
}
grouping refine-node-substmts {
description
"All substatements of a data-definition node that can be changed
by a refine statement.";
uses must-stmts;
leaf-list default {
type string;
description
"List of default substatement values.";
}
leaf config {
type boolean;
description
"Config substatement value.";
}
leaf mandatory {
type boolean;
description
"Mandatory substatement value.";
}
leaf min-elements {
type uint32;
description
"Min-elements substatement value.";
}
leaf max-elements {
type uint32;
description
"Max-elements substatement value.";
}
}
grouping node-substmts {
description
"All substatements of a data-definition node.";
uses if-feature-stmts {
when "../../locally-resolved";
}
uses when-stmts;
leaf description {
type string;
description
"Description substatement value.";
}
leaf reference {
type string;
description
"Reference substatement value.";
}
uses status-stmt;
uses refine-node-substmts;
leaf-list key {
type yang:yang-identifier;
description
"Leaf-list of nodes referenced by a key statement.";
}
leaf ordered-by {
type enumeration {
enum system {
description
"System-ordered list or leaf-list of items.";
}
enum user {
description
"User-ordered list or leaf-list of items.";
}
}
description
"Ordered-by substatement value.";
}
container type {
description
"Type substatement.";
uses type-substmts;
list union-type {
description
"List of a union type substatements.";
uses type-substmts;
}
}
leaf units {
type string;
description
"Units substatement value.";
}
list unique {
description
"List of unique substatements.";
leaf-list node {
type yang:yang-identifier;
description
"List of nodes referenced by a unique substatement.";
}
}
leaf presence {
type boolean;
description
"Indicates whether a presence substatement is defined for
the container in the compiled schema. The textual argument
of 'presence' is reported via the locally resolved module
comparison (see the 'presence' leaf in 'local-substmts').";
}
uses ext-instance-stmts;
}
grouping module-substmts {
description
"All non-data-definition substatements of a module.";
leaf yang-version {
type string;
description
"YANG version substatement value.";
}
leaf prefix {
when "../../../locally-resolved";
type string;
description
"Prefix substatement value.";
}
container import {
when "../../../locally-resolved";
presence "Exists only when there is a difference in this import.";
description
"Import substatements.";
leaf module {
type yang:yang-identifier;
mandatory true;
description
"Imported module.";
}
leaf prefix {
type yang:yang-identifier;
mandatory true;
description
"Imported module prefix.";
}
leaf revision-date {
type yanglib:revision-identifier;
description
"Imported module revision-date.";
}
leaf description {
type string;
description
"Description substatement value.";
}
leaf reference {
type string;
description
"Reference substatement value.";
}
uses ext-instance-stmts;
}
container include {
when "../../../locally-resolved";
presence
"Exists only when there is a difference in this include.";
description
"Include substatements.";
leaf submodule {
type yang:yang-identifier;
mandatory true;
description
"Included submodule.";
}
leaf revision-date {
type yanglib:revision-identifier;
description
"Included submodule revision-date.";
}
leaf description {
type string;
description
"Description substatement value.";
}
leaf reference {
type string;
description
"Reference substatement value.";
}
uses ext-instance-stmts;
}
leaf organization {
type string;
description
"Organization substatement value.";
}
leaf contact {
type string;
description
"Contact substatement value.";
}
leaf description {
type string;
description
"Description substatement value.";
}
leaf reference {
type string;
description
"Reference substatement value.";
}
container extension {
when "../../../locally-resolved";
presence
"Exists only when there is a difference in this extension.";
description
"Extension substatements.";
leaf name {
type yang:yang-identifier;
mandatory true;
description
"Extension name.";
}
leaf argument {
type yang:yang-identifier;
description
"Argument substatement value.";
}
uses status-stmt;
leaf description {
type string;
description
"Description substatement value.";
}
leaf reference {
type string;
description
"Reference substatement value.";
}
uses ext-instance-stmts;
}
container feature {
when "../../../locally-resolved";
presence
"Exists only when there is a difference in this feature.";
description
"Feature substatements.";
leaf name {
type yang:yang-identifier;
mandatory true;
description
"Feature name.";
}
uses if-feature-stmts;
uses status-stmt;
leaf description {
type string;
description
"Description substatement value.";
}
leaf reference {
type string;
description
"Reference substatement value.";
}
uses ext-instance-stmts;
}
container identity {
description
"Identity substatements.";
leaf name {
type yang:yang-identifier;
mandatory true;
description
"Identity statement name.";
}
uses if-feature-stmts {
when "../../../locally-resolved";
}
leaf-list base {
when "../../../../locally-resolved";
type yang:yang-identifier;
description
"List of bases of an identity.";
}
uses ext-instance-stmts;
}
container ext-instance {
presence
"Exists only when there is a difference in this
extension-instance.";
description
"Extension-instance substatements.";
uses ext-instance-stmt;
}
}
grouping local-substmts {
description
"All locally-resolved-module-only statements that can be direct
substatements of a module or nested in a node.";
uses if-feature-stmts;
uses when-stmts;
leaf description {
type string;
description
"Description substatement value.";
}
leaf reference {
type string;
description
"Reference substatement value.";
}
uses status-stmt;
uses refine-node-substmts;
container type {
description
"Type substatement.";
uses type-local-substmts;
list union-type {
description
"List of a union type substatements.";
uses type-local-substmts;
}
}
leaf units {
type string;
description
"Units substatement value.";
}
leaf presence {
type string;
description
"Presence substatement value.";
}
uses ext-instance-stmts;
}
grouping conformance-type {
description
"Conformance type of a change.";
leaf conformance {
type enumeration {
enum editorial {
description
"Editorial change.";
}
enum backwards-compatible {
description
"Backwards-compatible change.";
}
enum non-backwards-compatible {
description
"Non-backwards-compatible change.";
}
}
mandatory true;
description
"Conformance information of a change in the compared YANG
modules.";
}
}
grouping change-info {
description
"Details of a single change.";
list changed {
key "stmt";
min-elements 1;
description
"List of changes.";
leaf stmt {
type stmt-type;
description
"Changed statement.";
}
leaf parent-stmt {
type stmt-type;
description
"Parent statement of the changed statement.";
}
leaf change {
type enumeration {
enum modified {
description
"Statement existed and was modified.";
}
enum added {
description
"Statement was added.";
}
enum removed {
description
"Statement was removed.";
}
enum moved {
description
"Statement was moved and the position affects the
meaning.";
}
}
mandatory true;
description
"Type of change of the statement.";
}
uses conformance-type;
}
}
grouping module-params {
description
"Identification details of a processed YANG module.";
leaf module {
type yang:yang-identifier;
description
"Compared module name.";
}
leaf revision {
type revision-or-empty;
description
"Compared module revision.";
}
leaf version {
type ysv:version;
description
"Compared module semantic version, if defined.";
}
list submodule {
key "name revision";
leaf name {
type yang:yang-identifier;
description
"Submodule name.";
}
leaf revision {
type revision-or-empty;
description
"Submodule revision.";
}
description
"Submodule of the main module.";
}
leaf-list enabled-feature {
type yang:yang-identifier;
description
"All the enabled features of the module.";
}
}
grouping local-info {
description
"Information about all the changed locally-resolved-module-only statements.";
list local-comparison {
description
"Information about locally-resolved-module-only statement changes.";
leaf parent-path {
type schema-stmt-path;
description
"Path to the parent statement. Not set if a direct
substatement of module or submodule.";
}
leaf identifier {
type string;
mandatory true;
description
"Identifier of the statement, may include a prefix.";
}
leaf stmt-type {
type enumeration {
enum choice {
description
"YANG statement 'choice' node.";
}
enum case {
description
"YANG statement 'case' node.";
}
enum input {
description
"YANG statement 'input' node.";
}
enum output {
description
"YANG statement 'output' node.";
}
enum uses {
description
"YANG statement 'uses' node.";
}
enum grouping {
description
"YANG statement 'grouping' node.";
}
enum augment {
description
"YANG statement 'augment' node.";
}
enum refine {
description
"YANG statement 'refine' node.";
}
enum typedef {
description
"YANG statement 'typedef'.";
}
}
mandatory true;
description
"Type of the changed data-definition statement.";
}
uses change-info;
container old {
description
"Changed local statements in the older revision of the YANG
module.";
uses local-substmts;
}
container new {
description
"Changed local statements in the newer revision of the YANG
module.";
uses local-substmts;
}
}
}
grouping node-info {
description
"Information about all the changed nodes.";
list node-comparison {
key "node";
ordered-by user;
description
"Information about data-definition (node) statement substatement
changes. Keeps the traversed order of the nodes by the
algorithm. It SHOULD follow the depth-first search order.";
leaf node {
type schema-node-path;
description
"Path to the changed data-definition statement.";
}
leaf node-type {
type enumeration {
enum container {
description
"YANG statement 'container' node.";
}
enum leaf {
description
"YANG statement 'leaf' node.";
}
enum leaf-list {
description
"YANG statement 'leaf-list' node.";
}
enum list {
description
"YANG statement 'list' node.";
}
enum anydata {
description
"YANG statement 'anydata' node.";
}
enum anyxml {
description
"YANG statement 'anyxml' node.";
}
enum rpc {
description
"YANG statement 'rpc' node.";
}
enum action {
description
"YANG statement 'action' node.";
}
enum notification {
description
"YANG statement 'notification' node.";
}
}
mandatory true;
description
"Type of the changed data-definition statement.";
}
uses change-info;
container old {
description
"All the node substatements in the older revision of the YANG
module.";
uses node-substmts;
}
container new {
description
"All the node substatements in the newer revision of the YANG
module.";
uses node-substmts;
}
}
}
sx:structure schema-comparison {
description
"Schema comparison details.";
list comparison {
must "locally-resolved or fully-resolved" {
description
"As the comparison input, locally resolved module, fully
resolved module, or both must be used.";
}
description
"Instance of a schema comparison of 2 YANG modules in different
revisions with all their imports.";
leaf locally-resolved {
type empty;
description
"Locally resolved module has been used for the comparison.";
reference
"RFC XXXX Section 3.1.";
}
leaf fully-resolved {
type empty;
description
"Fully resolved schema has been used for the comparison.";
reference
"RFC XXXX Section 3.2.";
}
container source {
description
"Source module information.";
uses module-params;
}
list source-import {
when "../fully-resolved";
key "module revision";
description
"List of source module imported modules information.";
uses module-params;
}
container target {
description
"Target module information.";
uses module-params;
}
list target-import {
when "../fully-resolved";
key "module revision";
description
"List of target module imported modules information.";
uses module-params;
}
uses conformance-type;
list module-comparison {
description
"Information about direct module statement substatement
changes.";
uses change-info;
container old {
description
"Changed statements in the older revision of the YANG
module.";
uses module-substmts;
}
container new {
description
"Changed statements in the newer revision of the YANG
module.";
uses module-substmts;
}
}
uses local-info {
when "locally-resolved";
}
uses node-info;
}
}
}
<CODE ENDS>¶
The “ietf-yang-schema-comparison-output” YANG module has the following structure:¶
module: ietf-yang-schema-comparison-output
structure schema-comparison:
+-- comparison*
+-- locally-resolved? empty
+-- fully-resolved? empty
+-- source
| +-- module? yang:yang-identifier
| +-- revision? revision-or-empty
| +-- version? ysv:version
| +-- submodule* [name revision]
| | +-- name yang:yang-identifier
| | +-- revision revision-or-empty
| +-- enabled-feature* yang:yang-identifier
+-- source-import* [module revision]
| +-- module yang:yang-identifier
| +-- revision revision-or-empty
| +-- version? ysv:version
| +-- submodule* [name revision]
| | +-- name yang:yang-identifier
| | +-- revision revision-or-empty
| +-- enabled-feature* yang:yang-identifier
+-- target
| +-- module? yang:yang-identifier
| +-- revision? revision-or-empty
| +-- version? ysv:version
| +-- submodule* [name revision]
| | +-- name yang:yang-identifier
| | +-- revision revision-or-empty
| +-- enabled-feature* yang:yang-identifier
+-- target-import* [module revision]
| +-- module yang:yang-identifier
| +-- revision revision-or-empty
| +-- version? ysv:version
| +-- submodule* [name revision]
| | +-- name yang:yang-identifier
| | +-- revision revision-or-empty
| +-- enabled-feature* yang:yang-identifier
+-- conformance enumeration
+-- suggested-target-version ysv:version
+-- module-comparison*
| +-- changed* [stmt]
| | +-- stmt stmt-type
| | +-- parent-stmt? stmt-type
| | +-- change enumeration
| | +-- conformance enumeration
| +-- old
| | +-- yang-version? string
| | +-- prefix? string
| | +-- import!
| | | +-- module yang:yang-identifier
| | | +-- prefix yang:yang-identifier
| | | +-- revision-date? yanglib:revision-identifier
| | | +-- description? string
| | | +-- reference? string
| | | +-- ext-instance*
| | | +-- module yang:yang-identifier
| | | +-- name yang:yang-identifier
| | | +-- argument? string
| | | +-- substatements? anydata
| | +-- include!
| | | +-- submodule yang:yang-identifier
| | | +-- revision-date? yanglib:revision-identifier
| | | +-- description? string
| | | +-- reference? string
| | | +-- ext-instance*
| | | +-- module yang:yang-identifier
| | | +-- name yang:yang-identifier
| | | +-- argument? string
| | | +-- substatements? anydata
| | +-- organization? string
| | +-- contact? string
| | +-- description? string
| | +-- reference? string
| | +-- extension!
| | | +-- name yang:yang-identifier
| | | +-- argument? string
| | | +-- status enumeration
| | | +-- description? string
| | | +-- reference? string
| | | +-- ext-instance*
| | | +-- module yang:yang-identifier
| | | +-- name yang:yang-identifier
| | | +-- argument? string
| | | +-- substatements? anydata
| | +-- feature!
| | | +-- name yang:yang-identifier
| | | +-- if-feature* string
| | | +-- status enumeration
| | | +-- description? string
| | | +-- reference? string
| | | +-- ext-instance*
| | | +-- module yang:yang-identifier
| | | +-- name yang:yang-identifier
| | | +-- argument? string
| | | +-- substatements? anydata
| | +-- identity
| | | +-- name yang:yang-identifier
| | | +-- if-feature* string
| | | +-- base* string
| | | +-- ext-instance*
| | | +-- module yang:yang-identifier
| | | +-- name yang:yang-identifier
| | | +-- argument? string
| | | +-- substatements? anydata
| | +-- deviation!
| | | +-- target string
| | | +-- deviate*
| | | | +-- argument enumeration
| | | | +-- must*
| | | | | +-- condition? string
| | | | | +-- description? string
| | | | | +-- reference? string
| | | | | +-- error-message? string
| | | | | +-- error-app-tag? string
| | | | | +-- ext-instance*
| | | | | +-- module yang:yang-identifier
| | | | | +-- name yang:yang-identifier
| | | | | +-- argument? string
| | | | | +-- substatements? anydata
| | | | +-- default* string
| | | | +-- config? boolean
| | | | +-- mandatory? boolean
| | | | +-- min-elements? uint32
| | | | +-- max-elements? uint32
| | | | +-- type
| | | | | +-- name? string
| | | | | +-- range
| | | | | | +-- restriction? string
| | | | | | +-- description? string
| | | | | | +-- reference? string
| | | | | | +-- error-message? string
| | | | | | +-- error-app-tag? string
| | | | | | +-- ext-instance*
| | | | | | +-- module yang:yang-identifier
| | | | | | +-- name yang:yang-identifier
| | | | | | +-- argument? string
| | | | | | +-- substatements? anydata
| | | | | +-- length
| | | | | | +-- restriction? string
| | | | | | +-- description? string
| | | | | | +-- reference? string
| | | | | | +-- error-message? string
| | | | | | +-- error-app-tag? string
| | | | | | +-- ext-instance*
| | | | | | +-- module yang:yang-identifier
| | | | | | +-- name yang:yang-identifier
| | | | | | +-- argument? string
| | | | | | +-- substatements? anydata
| | | | | +-- fraction-digits? uint8
| | | | | +-- pattern*
| | | | | | +-- expression? string
| | | | | | +-- inverted? boolean
| | | | | | +-- description? string
| | | | | | +-- reference? string
| | | | | | +-- error-message? string
| | | | | | +-- error-app-tag? string
| | | | | | +-- ext-instance*
| | | | | | +-- module yang:yang-identifier
| | | | | | +-- name yang:yang-identifier
| | | | | | +-- argument? string
| | | | | | +-- substatements? anydata
| | | | | +-- enum* [name]
| | | | | | +-- name yang:yang-identifier
| | | | | | +-- if-feature* string
| | | | | | +-- description? string
| | | | | | +-- reference? string
| | | | | | +-- value? int32
| | | | | | +-- status enumeration
| | | | | | +-- ext-instance*
| | | | | | +-- module yang:yang-identifier
| | | | | | +-- name yang:yang-identifier
| | | | | | +-- argument? string
| | | | | | +-- substatements? anydata
| | | | | +-- bit* [name]
| | | | | | +-- name yang:yang-identifier
| | | | | | +-- if-feature* string
| | | | | | +-- description? string
| | | | | | +-- reference? string
| | | | | | +-- position? uint32
| | | | | | +-- status enumeration
| | | | | | +-- ext-instance*
| | | | | | +-- module yang:yang-identifier
| | | | | | +-- name yang:yang-identifier
| | | | | | +-- argument? string
| | | | | | +-- substatements? anydata
| | | | | +-- path? string
| | | | | +-- require-instance? boolean
| | | | | +-- base* string
| | | | | +-- ext-instance*
| | | | | | +-- module yang:yang-identifier
| | | | | | +-- name yang:yang-identifier
| | | | | | +-- argument? string
| | | | | | +-- substatements? anydata
| | | | | +-- union-type*
| | | | | +-- name? string
| | | | | +-- range
| | | | | | +-- restriction? string
| | | | | | +-- description? string
| | | | | | +-- reference? string
| | | | | | +-- error-message? string
| | | | | | +-- error-app-tag? string
| | | | | | +-- ext-instance*
| | | | | | +-- module yang:yang-identifier
| | | | | | +-- name yang:yang-identifier
| | | | | | +-- argument? string
| | | | | | +-- substatements? anydata
| | | | | +-- length
| | | | | | +-- restriction? string
| | | | | | +-- description? string
| | | | | | +-- reference? string
| | | | | | +-- error-message? string
| | | | | | +-- error-app-tag? string
| | | | | | +-- ext-instance*
| | | | | | +-- module yang:yang-identifier
| | | | | | +-- name yang:yang-identifier
| | | | | | +-- argument? string
| | | | | | +-- substatements? anydata
| | | | | +-- fraction-digits? uint8
| | | | | +-- pattern*
| | | | | | +-- expression? string
| | | | | | +-- inverted? boolean
| | | | | | +-- description? string
| | | | | | +-- reference? string
| | | | | | +-- error-message? string
| | | | | | +-- error-app-tag? string
| | | | | | +-- ext-instance*
| | | | | | +-- module yang:yang-identifier
| | | | | | +-- name yang:yang-identifier
| | | | | | +-- argument? string
| | | | | | +-- substatements? anydata
| | | | | +-- enum* [name]
| | | | | | +-- name yang:yang-identifier
| | | | | | +-- if-feature* string
| | | | | | +-- description? string
| | | | | | +-- reference? string
| | | | | | +-- value? int32
| | | | | | +-- status enumeration
| | | | | | +-- ext-instance*
| | | | | | +-- module yang:yang-identifier
| | | | | | +-- name yang:yang-identifier
| | | | | | +-- argument? string
| | | | | | +-- substatements? anydata
| | | | | +-- bit* [name]
| | | | | | +-- name yang:yang-identifier
| | | | | | +-- if-feature* string
| | | | | | +-- description? string
| | | | | | +-- reference? string
| | | | | | +-- position? uint32
| | | | | | +-- status enumeration
| | | | | | +-- ext-instance*
| | | | | | +-- module yang:yang-identifier
| | | | | | +-- name yang:yang-identifier
| | | | | | +-- argument? string
| | | | | | +-- substatements? anydata
| | | | | +-- path? string
| | | | | +-- require-instance? boolean
| | | | | +-- base* string
| | | | | +-- ext-instance*
| | | | | +-- module yang:yang-identifier
| | | | | +-- name yang:yang-identifier
| | | | | +-- argument? string
| | | | | +-- substatements? anydata
| | | | +-- units? string
| | | | +-- unique*
| | | | +-- node* yang:yang-identifier
| | | +-- description? string
| | | +-- reference? string
| | | +-- ext-instance*
| | | +-- module yang:yang-identifier
| | | +-- name yang:yang-identifier
| | | +-- argument? string
| | | +-- substatements? anydata
| | +-- ext-instance!
| | +-- module yang:yang-identifier
| | +-- name yang:yang-identifier
| | +-- argument? string
| | +-- substatements? anydata
| +-- new
| +-- yang-version? string
| +-- prefix? string
| +-- import!
| | +-- module yang:yang-identifier
| | +-- prefix yang:yang-identifier
| | +-- revision-date? yanglib:revision-identifier
| | +-- description? string
| | +-- reference? string
| | +-- ext-instance*
| | +-- module yang:yang-identifier
| | +-- name yang:yang-identifier
| | +-- argument? string
| | +-- substatements? anydata
| +-- include!
| | +-- submodule yang:yang-identifier
| | +-- revision-date? yanglib:revision-identifier
| | +-- description? string
| | +-- reference? string
| | +-- ext-instance*
| | +-- module yang:yang-identifier
| | +-- name yang:yang-identifier
| | +-- argument? string
| | +-- substatements? anydata
| +-- organization? string
| +-- contact? string
| +-- description? string
| +-- reference? string
| +-- extension!
| | +-- name yang:yang-identifier
| | +-- argument? string
| | +-- status enumeration
| | +-- description? string
| | +-- reference? string
| | +-- ext-instance*
| | +-- module yang:yang-identifier
| | +-- name yang:yang-identifier
| | +-- argument? string
| | +-- substatements? anydata
| +-- feature!
| | +-- name yang:yang-identifier
| | +-- if-feature* string
| | +-- status enumeration
| | +-- description? string
| | +-- reference? string
| | +-- ext-instance*
| | +-- module yang:yang-identifier
| | +-- name yang:yang-identifier
| | +-- argument? string
| | +-- substatements? anydata
| +-- identity
| | +-- name yang:yang-identifier
| | +-- if-feature* string
| | +-- base* string
| | +-- ext-instance*
| | +-- module yang:yang-identifier
| | +-- name yang:yang-identifier
| | +-- argument? string
| | +-- substatements? anydata
| +-- deviation!
| | +-- target string
| | +-- deviate*
| | | +-- argument enumeration
| | | +-- must*
| | | | +-- condition? string
| | | | +-- description? string
| | | | +-- reference? string
| | | | +-- error-message? string
| | | | +-- error-app-tag? string
| | | | +-- ext-instance*
| | | | +-- module yang:yang-identifier
| | | | +-- name yang:yang-identifier
| | | | +-- argument? string
| | | | +-- substatements? anydata
| | | +-- default* string
| | | +-- config? boolean
| | | +-- mandatory? boolean
| | | +-- min-elements? uint32
| | | +-- max-elements? uint32
| | | +-- type
| | | | +-- name? string
| | | | +-- range
| | | | | +-- restriction? string
| | | | | +-- description? string
| | | | | +-- reference? string
| | | | | +-- error-message? string
| | | | | +-- error-app-tag? string
| | | | | +-- ext-instance*
| | | | | +-- module yang:yang-identifier
| | | | | +-- name yang:yang-identifier
| | | | | +-- argument? string
| | | | | +-- substatements? anydata
| | | | +-- length
| | | | | +-- restriction? string
| | | | | +-- description? string
| | | | | +-- reference? string
| | | | | +-- error-message? string
| | | | | +-- error-app-tag? string
| | | | | +-- ext-instance*
| | | | | +-- module yang:yang-identifier
| | | | | +-- name yang:yang-identifier
| | | | | +-- argument? string
| | | | | +-- substatements? anydata
| | | | +-- fraction-digits? uint8
| | | | +-- pattern*
| | | | | +-- expression? string
| | | | | +-- inverted? boolean
| | | | | +-- description? string
| | | | | +-- reference? string
| | | | | +-- error-message? string
| | | | | +-- error-app-tag? string
| | | | | +-- ext-instance*
| | | | | +-- module yang:yang-identifier
| | | | | +-- name yang:yang-identifier
| | | | | +-- argument? string
| | | | | +-- substatements? anydata
| | | | +-- enum* [name]
| | | | | +-- name yang:yang-identifier
| | | | | +-- if-feature* string
| | | | | +-- description? string
| | | | | +-- reference? string
| | | | | +-- value? int32
| | | | | +-- status enumeration
| | | | | +-- ext-instance*
| | | | | +-- module yang:yang-identifier
| | | | | +-- name yang:yang-identifier
| | | | | +-- argument? string
| | | | | +-- substatements? anydata
| | | | +-- bit* [name]
| | | | | +-- name yang:yang-identifier
| | | | | +-- if-feature* string
| | | | | +-- description? string
| | | | | +-- reference? string
| | | | | +-- position? uint32
| | | | | +-- status enumeration
| | | | | +-- ext-instance*
| | | | | +-- module yang:yang-identifier
| | | | | +-- name yang:yang-identifier
| | | | | +-- argument? string
| | | | | +-- substatements? anydata
| | | | +-- path? string
| | | | +-- require-instance? boolean
| | | | +-- base* string
| | | | +-- ext-instance*
| | | | | +-- module yang:yang-identifier
| | | | | +-- name yang:yang-identifier
| | | | | +-- argument? string
| | | | | +-- substatements? anydata
| | | | +-- union-type*
| | | | +-- name? string
| | | | +-- range
| | | | | +-- restriction? string
| | | | | +-- description? string
| | | | | +-- reference? string
| | | | | +-- error-message? string
| | | | | +-- error-app-tag? string
| | | | | +-- ext-instance*
| | | | | +-- module yang:yang-identifier
| | | | | +-- name yang:yang-identifier
| | | | | +-- argument? string
| | | | | +-- substatements? anydata
| | | | +-- length
| | | | | +-- restriction? string
| | | | | +-- description? string
| | | | | +-- reference? string
| | | | | +-- error-message? string
| | | | | +-- error-app-tag? string
| | | | | +-- ext-instance*
| | | | | +-- module yang:yang-identifier
| | | | | +-- name yang:yang-identifier
| | | | | +-- argument? string
| | | | | +-- substatements? anydata
| | | | +-- fraction-digits? uint8
| | | | +-- pattern*
| | | | | +-- expression? string
| | | | | +-- inverted? boolean
| | | | | +-- description? string
| | | | | +-- reference? string
| | | | | +-- error-message? string
| | | | | +-- error-app-tag? string
| | | | | +-- ext-instance*
| | | | | +-- module yang:yang-identifier
| | | | | +-- name yang:yang-identifier
| | | | | +-- argument? string
| | | | | +-- substatements? anydata
| | | | +-- enum* [name]
| | | | | +-- name yang:yang-identifier
| | | | | +-- if-feature* string
| | | | | +-- description? string
| | | | | +-- reference? string
| | | | | +-- value? int32
| | | | | +-- status enumeration
| | | | | +-- ext-instance*
| | | | | +-- module yang:yang-identifier
| | | | | +-- name yang:yang-identifier
| | | | | +-- argument? string
| | | | | +-- substatements? anydata
| | | | +-- bit* [name]
| | | | | +-- name yang:yang-identifier
| | | | | +-- if-feature* string
| | | | | +-- description? string
| | | | | +-- reference? string
| | | | | +-- position? uint32
| | | | | +-- status enumeration
| | | | | +-- ext-instance*
| | | | | +-- module yang:yang-identifier
| | | | | +-- name yang:yang-identifier
| | | | | +-- argument? string
| | | | | +-- substatements? anydata
| | | | +-- path? string
| | | | +-- require-instance? boolean
| | | | +-- base* string
| | | | +-- ext-instance*
| | | | +-- module yang:yang-identifier
| | | | +-- name yang:yang-identifier
| | | | +-- argument? string
| | | | +-- substatements? anydata
| | | +-- units? string
| | | +-- unique*
| | | +-- node* yang:yang-identifier
| | +-- description? string
| | +-- reference? string
| | +-- ext-instance*
| | +-- module yang:yang-identifier
| | +-- name yang:yang-identifier
| | +-- argument? string
| | +-- substatements? anydata
| +-- ext-instance!
| +-- module yang:yang-identifier
| +-- name yang:yang-identifier
| +-- argument? string
| +-- substatements? anydata
+-- local-comparison*
| +-- parent-path? schema-stmt-path
| +-- identifier string
| +-- stmt-type enumeration
| +-- changed* [stmt]
| | +-- stmt stmt-type
| | +-- parent-stmt? stmt-type
| | +-- change enumeration
| | +-- conformance enumeration
| +-- old
| | +-- if-feature* string
| | +-- when*
| | | +-- condition? string
| | | +-- description? string
| | | +-- reference? string
| | | +-- status enumeration
| | | +-- ext-instance*
| | | +-- module yang:yang-identifier
| | | +-- name yang:yang-identifier
| | | +-- argument? string
| | | +-- substatements? anydata
| | +-- description? string
| | +-- reference? string
| | +-- status enumeration
| | +-- must*
| | | +-- condition? string
| | | +-- description? string
| | | +-- reference? string
| | | +-- error-message? string
| | | +-- error-app-tag? string
| | | +-- ext-instance*
| | | +-- module yang:yang-identifier
| | | +-- name yang:yang-identifier
| | | +-- argument? string
| | | +-- substatements? anydata
| | +-- default* string
| | +-- config? boolean
| | +-- mandatory? boolean
| | +-- min-elements? uint32
| | +-- max-elements? uint32
| | +-- type
| | | +-- name? string
| | | +-- range
| | | | +-- restriction? string
| | | | +-- description? string
| | | | +-- reference? string
| | | | +-- error-message? string
| | | | +-- error-app-tag? string
| | | | +-- ext-instance*
| | | | +-- module yang:yang-identifier
| | | | +-- name yang:yang-identifier
| | | | +-- argument? string
| | | | +-- substatements? anydata
| | | +-- length
| | | | +-- restriction? string
| | | | +-- description? string
| | | | +-- reference? string
| | | | +-- error-message? string
| | | | +-- error-app-tag? string
| | | | +-- ext-instance*
| | | | +-- module yang:yang-identifier
| | | | +-- name yang:yang-identifier
| | | | +-- argument? string
| | | | +-- substatements? anydata
| | | +-- fraction-digits? uint8
| | | +-- pattern*
| | | | +-- expression? string
| | | | +-- inverted? boolean
| | | | +-- description? string
| | | | +-- reference? string
| | | | +-- error-message? string
| | | | +-- error-app-tag? string
| | | | +-- ext-instance*
| | | | +-- module yang:yang-identifier
| | | | +-- name yang:yang-identifier
| | | | +-- argument? string
| | | | +-- substatements? anydata
| | | +-- enum* [name]
| | | | +-- name yang:yang-identifier
| | | | +-- if-feature* string
| | | | +-- description? string
| | | | +-- reference? string
| | | | +-- value? int32
| | | | +-- status enumeration
| | | | +-- ext-instance*
| | | | +-- module yang:yang-identifier
| | | | +-- name yang:yang-identifier
| | | | +-- argument? string
| | | | +-- substatements? anydata
| | | +-- bit* [name]
| | | | +-- name yang:yang-identifier
| | | | +-- if-feature* string
| | | | +-- description? string
| | | | +-- reference? string
| | | | +-- position? uint32
| | | | +-- status enumeration
| | | | +-- ext-instance*
| | | | +-- module yang:yang-identifier
| | | | +-- name yang:yang-identifier
| | | | +-- argument? string
| | | | +-- substatements? anydata
| | | +-- path? string
| | | +-- require-instance? boolean
| | | +-- base* string
| | | +-- ext-instance*
| | | | +-- module yang:yang-identifier
| | | | +-- name yang:yang-identifier
| | | | +-- argument? string
| | | | +-- substatements? anydata
| | | +-- union-type*
| | | +-- name? string
| | | +-- range
| | | | +-- restriction? string
| | | | +-- description? string
| | | | +-- reference? string
| | | | +-- error-message? string
| | | | +-- error-app-tag? string
| | | | +-- ext-instance*
| | | | +-- module yang:yang-identifier
| | | | +-- name yang:yang-identifier
| | | | +-- argument? string
| | | | +-- substatements? anydata
| | | +-- length
| | | | +-- restriction? string
| | | | +-- description? string
| | | | +-- reference? string
| | | | +-- error-message? string
| | | | +-- error-app-tag? string
| | | | +-- ext-instance*
| | | | +-- module yang:yang-identifier
| | | | +-- name yang:yang-identifier
| | | | +-- argument? string
| | | | +-- substatements? anydata
| | | +-- fraction-digits? uint8
| | | +-- pattern*
| | | | +-- expression? string
| | | | +-- inverted? boolean
| | | | +-- description? string
| | | | +-- reference? string
| | | | +-- error-message? string
| | | | +-- error-app-tag? string
| | | | +-- ext-instance*
| | | | +-- module yang:yang-identifier
| | | | +-- name yang:yang-identifier
| | | | +-- argument? string
| | | | +-- substatements? anydata
| | | +-- enum* [name]
| | | | +-- name yang:yang-identifier
| | | | +-- if-feature* string
| | | | +-- description? string
| | | | +-- reference? string
| | | | +-- value? int32
| | | | +-- status enumeration
| | | | +-- ext-instance*
| | | | +-- module yang:yang-identifier
| | | | +-- name yang:yang-identifier
| | | | +-- argument? string
| | | | +-- substatements? anydata
| | | +-- bit* [name]
| | | | +-- name yang:yang-identifier
| | | | +-- if-feature* string
| | | | +-- description? string
| | | | +-- reference? string
| | | | +-- position? uint32
| | | | +-- status enumeration
| | | | +-- ext-instance*
| | | | +-- module yang:yang-identifier
| | | | +-- name yang:yang-identifier
| | | | +-- argument? string
| | | | +-- substatements? anydata
| | | +-- path? string
| | | +-- require-instance? boolean
| | | +-- base* string
| | | +-- ext-instance*
| | | +-- module yang:yang-identifier
| | | +-- name yang:yang-identifier
| | | +-- argument? string
| | | +-- substatements? anydata
| | +-- units? string
| | +-- key? string
| | +-- unique* string
| | +-- presence? string
| | +-- ext-instance*
| | +-- module yang:yang-identifier
| | +-- name yang:yang-identifier
| | +-- argument? string
| | +-- substatements? anydata
| +-- new
| +-- if-feature* string
| +-- when*
| | +-- condition? string
| | +-- description? string
| | +-- reference? string
| | +-- status enumeration
| | +-- ext-instance*
| | +-- module yang:yang-identifier
| | +-- name yang:yang-identifier
| | +-- argument? string
| | +-- substatements? anydata
| +-- description? string
| +-- reference? string
| +-- status enumeration
| +-- must*
| | +-- condition? string
| | +-- description? string
| | +-- reference? string
| | +-- error-message? string
| | +-- error-app-tag? string
| | +-- ext-instance*
| | +-- module yang:yang-identifier
| | +-- name yang:yang-identifier
| | +-- argument? string
| | +-- substatements? anydata
| +-- default* string
| +-- config? boolean
| +-- mandatory? boolean
| +-- min-elements? uint32
| +-- max-elements? uint32
| +-- type
| | +-- name? string
| | +-- range
| | | +-- restriction? string
| | | +-- description? string
| | | +-- reference? string
| | | +-- error-message? string
| | | +-- error-app-tag? string
| | | +-- ext-instance*
| | | +-- module yang:yang-identifier
| | | +-- name yang:yang-identifier
| | | +-- argument? string
| | | +-- substatements? anydata
| | +-- length
| | | +-- restriction? string
| | | +-- description? string
| | | +-- reference? string
| | | +-- error-message? string
| | | +-- error-app-tag? string
| | | +-- ext-instance*
| | | +-- module yang:yang-identifier
| | | +-- name yang:yang-identifier
| | | +-- argument? string
| | | +-- substatements? anydata
| | +-- fraction-digits? uint8
| | +-- pattern*
| | | +-- expression? string
| | | +-- inverted? boolean
| | | +-- description? string
| | | +-- reference? string
| | | +-- error-message? string
| | | +-- error-app-tag? string
| | | +-- ext-instance*
| | | +-- module yang:yang-identifier
| | | +-- name yang:yang-identifier
| | | +-- argument? string
| | | +-- substatements? anydata
| | +-- enum* [name]
| | | +-- name yang:yang-identifier
| | | +-- if-feature* string
| | | +-- description? string
| | | +-- reference? string
| | | +-- value? int32
| | | +-- status enumeration
| | | +-- ext-instance*
| | | +-- module yang:yang-identifier
| | | +-- name yang:yang-identifier
| | | +-- argument? string
| | | +-- substatements? anydata
| | +-- bit* [name]
| | | +-- name yang:yang-identifier
| | | +-- if-feature* string
| | | +-- description? string
| | | +-- reference? string
| | | +-- position? uint32
| | | +-- status enumeration
| | | +-- ext-instance*
| | | +-- module yang:yang-identifier
| | | +-- name yang:yang-identifier
| | | +-- argument? string
| | | +-- substatements? anydata
| | +-- path? string
| | +-- require-instance? boolean
| | +-- base* string
| | +-- ext-instance*
| | | +-- module yang:yang-identifier
| | | +-- name yang:yang-identifier
| | | +-- argument? string
| | | +-- substatements? anydata
| | +-- union-type*
| | +-- name? string
| | +-- range
| | | +-- restriction? string
| | | +-- description? string
| | | +-- reference? string
| | | +-- error-message? string
| | | +-- error-app-tag? string
| | | +-- ext-instance*
| | | +-- module yang:yang-identifier
| | | +-- name yang:yang-identifier
| | | +-- argument? string
| | | +-- substatements? anydata
| | +-- length
| | | +-- restriction? string
| | | +-- description? string
| | | +-- reference? string
| | | +-- error-message? string
| | | +-- error-app-tag? string
| | | +-- ext-instance*
| | | +-- module yang:yang-identifier
| | | +-- name yang:yang-identifier
| | | +-- argument? string
| | | +-- substatements? anydata
| | +-- fraction-digits? uint8
| | +-- pattern*
| | | +-- expression? string
| | | +-- inverted? boolean
| | | +-- description? string
| | | +-- reference? string
| | | +-- error-message? string
| | | +-- error-app-tag? string
| | | +-- ext-instance*
| | | +-- module yang:yang-identifier
| | | +-- name yang:yang-identifier
| | | +-- argument? string
| | | +-- substatements? anydata
| | +-- enum* [name]
| | | +-- name yang:yang-identifier
| | | +-- if-feature* string
| | | +-- description? string
| | | +-- reference? string
| | | +-- value? int32
| | | +-- status enumeration
| | | +-- ext-instance*
| | | +-- module yang:yang-identifier
| | | +-- name yang:yang-identifier
| | | +-- argument? string
| | | +-- substatements? anydata
| | +-- bit* [name]
| | | +-- name yang:yang-identifier
| | | +-- if-feature* string
| | | +-- description? string
| | | +-- reference? string
| | | +-- position? uint32
| | | +-- status enumeration
| | | +-- ext-instance*
| | | +-- module yang:yang-identifier
| | | +-- name yang:yang-identifier
| | | +-- argument? string
| | | +-- substatements? anydata
| | +-- path? string
| | +-- require-instance? boolean
| | +-- base* string
| | +-- ext-instance*
| | +-- module yang:yang-identifier
| | +-- name yang:yang-identifier
| | +-- argument? string
| | +-- substatements? anydata
| +-- units? string
| +-- key? string
| +-- unique* string
| +-- presence? string
| +-- ext-instance*
| +-- module yang:yang-identifier
| +-- name yang:yang-identifier
| +-- argument? string
| +-- substatements? anydata
+-- node-comparison* [node]
+-- node schema-node-path
+-- node-type enumeration
+-- changed* [stmt]
| +-- stmt stmt-type
| +-- parent-stmt? stmt-type
| +-- change enumeration
| +-- conformance enumeration
+-- old
| +-- if-feature* string
| +-- when*
| | +-- condition? string
| | +-- description? string
| | +-- reference? string
| | +-- status enumeration
| | +-- ext-instance*
| | +-- module yang:yang-identifier
| | +-- name yang:yang-identifier
| | +-- argument? string
| | +-- substatements? anydata
| +-- description? string
| +-- reference? string
| +-- status enumeration
| +-- must*
| | +-- condition? string
| | +-- description? string
| | +-- reference? string
| | +-- error-message? string
| | +-- error-app-tag? string
| | +-- ext-instance*
| | +-- module yang:yang-identifier
| | +-- name yang:yang-identifier
| | +-- argument? string
| | +-- substatements? anydata
| +-- default* string
| +-- config? boolean
| +-- mandatory? boolean
| +-- min-elements? uint32
| +-- max-elements? uint32
| +-- key* yang:yang-identifier
| +-- ordered-by? enumeration
| +-- type
| | +-- name? string
| | +-- range
| | | +-- restriction? string
| | | +-- description? string
| | | +-- reference? string
| | | +-- error-message? string
| | | +-- error-app-tag? string
| | | +-- ext-instance*
| | | +-- module yang:yang-identifier
| | | +-- name yang:yang-identifier
| | | +-- argument? string
| | | +-- substatements? anydata
| | +-- length
| | | +-- restriction? string
| | | +-- description? string
| | | +-- reference? string
| | | +-- error-message? string
| | | +-- error-app-tag? string
| | | +-- ext-instance*
| | | +-- module yang:yang-identifier
| | | +-- name yang:yang-identifier
| | | +-- argument? string
| | | +-- substatements? anydata
| | +-- fraction-digits? uint8
| | +-- pattern*
| | | +-- expression? string
| | | +-- inverted? boolean
| | | +-- description? string
| | | +-- reference? string
| | | +-- error-message? string
| | | +-- error-app-tag? string
| | | +-- ext-instance*
| | | +-- module yang:yang-identifier
| | | +-- name yang:yang-identifier
| | | +-- argument? string
| | | +-- substatements? anydata
| | +-- enum* [name]
| | | +-- name yang:yang-identifier
| | | +-- if-feature* string
| | | +-- description? string
| | | +-- reference? string
| | | +-- value? int32
| | | +-- status enumeration
| | | +-- ext-instance*
| | | +-- module yang:yang-identifier
| | | +-- name yang:yang-identifier
| | | +-- argument? string
| | | +-- substatements? anydata
| | +-- bit* [name]
| | | +-- name yang:yang-identifier
| | | +-- if-feature* string
| | | +-- description? string
| | | +-- reference? string
| | | +-- position? uint32
| | | +-- status enumeration
| | | +-- ext-instance*
| | | +-- module yang:yang-identifier
| | | +-- name yang:yang-identifier
| | | +-- argument? string
| | | +-- substatements? anydata
| | +-- path? string
| | +-- require-instance? boolean
| | +-- base* string
| | +-- ext-instance*
| | | +-- module yang:yang-identifier
| | | +-- name yang:yang-identifier
| | | +-- argument? string
| | | +-- substatements? anydata
| | +-- union-type*
| | +-- name? string
| | +-- range
| | | +-- restriction? string
| | | +-- description? string
| | | +-- reference? string
| | | +-- error-message? string
| | | +-- error-app-tag? string
| | | +-- ext-instance*
| | | +-- module yang:yang-identifier
| | | +-- name yang:yang-identifier
| | | +-- argument? string
| | | +-- substatements? anydata
| | +-- length
| | | +-- restriction? string
| | | +-- description? string
| | | +-- reference? string
| | | +-- error-message? string
| | | +-- error-app-tag? string
| | | +-- ext-instance*
| | | +-- module yang:yang-identifier
| | | +-- name yang:yang-identifier
| | | +-- argument? string
| | | +-- substatements? anydata
| | +-- fraction-digits? uint8
| | +-- pattern*
| | | +-- expression? string
| | | +-- inverted? boolean
| | | +-- description? string
| | | +-- reference? string
| | | +-- error-message? string
| | | +-- error-app-tag? string
| | | +-- ext-instance*
| | | +-- module yang:yang-identifier
| | | +-- name yang:yang-identifier
| | | +-- argument? string
| | | +-- substatements? anydata
| | +-- enum* [name]
| | | +-- name yang:yang-identifier
| | | +-- if-feature* string
| | | +-- description? string
| | | +-- reference? string
| | | +-- value? int32
| | | +-- status enumeration
| | | +-- ext-instance*
| | | +-- module yang:yang-identifier
| | | +-- name yang:yang-identifier
| | | +-- argument? string
| | | +-- substatements? anydata
| | +-- bit* [name]
| | | +-- name yang:yang-identifier
| | | +-- if-feature* string
| | | +-- description? string
| | | +-- reference? string
| | | +-- position? uint32
| | | +-- status enumeration
| | | +-- ext-instance*
| | | +-- module yang:yang-identifier
| | | +-- name yang:yang-identifier
| | | +-- argument? string
| | | +-- substatements? anydata
| | +-- path? string
| | +-- require-instance? boolean
| | +-- base* string
| | +-- ext-instance*
| | +-- module yang:yang-identifier
| | +-- name yang:yang-identifier
| | +-- argument? string
| | +-- substatements? anydata
| +-- units? string
| +-- unique*
| | +-- node* yang:yang-identifier
| +-- presence? string
| +-- ext-instance*
| +-- module yang:yang-identifier
| +-- name yang:yang-identifier
| +-- argument? string
| +-- substatements? anydata
+-- new
+-- if-feature* string
+-- when*
| +-- condition? string
| +-- description? string
| +-- reference? string
| +-- status enumeration
| +-- ext-instance*
| +-- module yang:yang-identifier
| +-- name yang:yang-identifier
| +-- argument? string
| +-- substatements? anydata
+-- description? string
+-- reference? string
+-- status enumeration
+-- must*
| +-- condition? string
| +-- description? string
| +-- reference? string
| +-- error-message? string
| +-- error-app-tag? string
| +-- ext-instance*
| +-- module yang:yang-identifier
| +-- name yang:yang-identifier
| +-- argument? string
| +-- substatements? anydata
+-- default* string
+-- config? boolean
+-- mandatory? boolean
+-- min-elements? uint32
+-- max-elements? uint32
+-- key* yang:yang-identifier
+-- ordered-by? enumeration
+-- type
| +-- name? string
| +-- range
| | +-- restriction? string
| | +-- description? string
| | +-- reference? string
| | +-- error-message? string
| | +-- error-app-tag? string
| | +-- ext-instance*
| | +-- module yang:yang-identifier
| | +-- name yang:yang-identifier
| | +-- argument? string
| | +-- substatements? anydata
| +-- length
| | +-- restriction? string
| | +-- description? string
| | +-- reference? string
| | +-- error-message? string
| | +-- error-app-tag? string
| | +-- ext-instance*
| | +-- module yang:yang-identifier
| | +-- name yang:yang-identifier
| | +-- argument? string
| | +-- substatements? anydata
| +-- fraction-digits? uint8
| +-- pattern*
| | +-- expression? string
| | +-- inverted? boolean
| | +-- description? string
| | +-- reference? string
| | +-- error-message? string
| | +-- error-app-tag? string
| | +-- ext-instance*
| | +-- module yang:yang-identifier
| | +-- name yang:yang-identifier
| | +-- argument? string
| | +-- substatements? anydata
| +-- enum* [name]
| | +-- name yang:yang-identifier
| | +-- if-feature* string
| | +-- description? string
| | +-- reference? string
| | +-- value? int32
| | +-- status enumeration
| | +-- ext-instance*
| | +-- module yang:yang-identifier
| | +-- name yang:yang-identifier
| | +-- argument? string
| | +-- substatements? anydata
| +-- bit* [name]
| | +-- name yang:yang-identifier
| | +-- if-feature* string
| | +-- description? string
| | +-- reference? string
| | +-- position? uint32
| | +-- status enumeration
| | +-- ext-instance*
| | +-- module yang:yang-identifier
| | +-- name yang:yang-identifier
| | +-- argument? string
| | +-- substatements? anydata
| +-- path? string
| +-- require-instance? boolean
| +-- base* string
| +-- ext-instance*
| | +-- module yang:yang-identifier
| | +-- name yang:yang-identifier
| | +-- argument? string
| | +-- substatements? anydata
| +-- union-type*
| +-- name? string
| +-- range
| | +-- restriction? string
| | +-- description? string
| | +-- reference? string
| | +-- error-message? string
| | +-- error-app-tag? string
| | +-- ext-instance*
| | +-- module yang:yang-identifier
| | +-- name yang:yang-identifier
| | +-- argument? string
| | +-- substatements? anydata
| +-- length
| | +-- restriction? string
| | +-- description? string
| | +-- reference? string
| | +-- error-message? string
| | +-- error-app-tag? string
| | +-- ext-instance*
| | +-- module yang:yang-identifier
| | +-- name yang:yang-identifier
| | +-- argument? string
| | +-- substatements? anydata
| +-- fraction-digits? uint8
| +-- pattern*
| | +-- expression? string
| | +-- inverted? boolean
| | +-- description? string
| | +-- reference? string
| | +-- error-message? string
| | +-- error-app-tag? string
| | +-- ext-instance*
| | +-- module yang:yang-identifier
| | +-- name yang:yang-identifier
| | +-- argument? string
| | +-- substatements? anydata
| +-- enum* [name]
| | +-- name yang:yang-identifier
| | +-- if-feature* string
| | +-- description? string
| | +-- reference? string
| | +-- value? int32
| | +-- status enumeration
| | +-- ext-instance*
| | +-- module yang:yang-identifier
| | +-- name yang:yang-identifier
| | +-- argument? string
| | +-- substatements? anydata
| +-- bit* [name]
| | +-- name yang:yang-identifier
| | +-- if-feature* string
| | +-- description? string
| | +-- reference? string
| | +-- position? uint32
| | +-- status enumeration
| | +-- ext-instance*
| | +-- module yang:yang-identifier
| | +-- name yang:yang-identifier
| | +-- argument? string
| | +-- substatements? anydata
| +-- path? string
| +-- require-instance? boolean
| +-- base* string
| +-- ext-instance*
| +-- module yang:yang-identifier
| +-- name yang:yang-identifier
| +-- argument? string
| +-- substatements? anydata
+-- units? string
+-- unique*
| +-- node* yang:yang-identifier
+-- presence? string
+-- ext-instance*
+-- module yang:yang-identifier
+-- name yang:yang-identifier
+-- argument? string
+-- substatements? anydata
¶
This appendix clarifies the general principles based on which statement changes are categorized. They are not meant to replace any specification but rather help with understanding it.¶
An editorial change does not affect valid YANG data of the semantics of the YANG module in any way. That is, it does not make the valid data value space smaller or larger and it must remain exactly the same as in the module revision without the change. Also, for a change to be editorial, it must not affect any YANG module importing the changed YANG module.¶
In addition to obvious editorial changes such as fixing a typo in a "description", changing the local "prefix" of the module is also categorized as editorial because it does not affect importing modules. Or, replacing a "uses" statement directly with the nodes in the referenced "grouping" without any other changes.¶
For a change to be backwards-compatible, it has to expand the value space of valid YANG data. That is, all the valid YANG data nodes and values before the change must remain valid but additional nodes or values can also become valid after the change. Also, backwards-compatible changes may influence importing modules but must not cause them to become invalid. In other words, they may expose new statements whose removal would then be considered a non-backwards-compatible change but generally must not change the already exposed statements.¶
For some examples, the majority of possible backwards-compatible changes are specifically mentioned directly in Section 11 of [RFC7950].¶
If a change is not editorial nor backwards-compatible, it is then categorized as non-backwards-compatible. Such changes shrink the value space of valid YANG data, causing some previously valid nodes or values to no longer be valid. Also, any change that may cause an importing module to become invalid according to the YANG specification must be non-backwards-compatible.¶
Examples of less common or less obvious compatibility-breaking changes are changing the "yang-version" of a YANG module or expanding the size of a "type". The former change may break importing modules because of specific rules defined for the "import" statement and the target module's YANG version. Changing a "type" of a leaf from "uint32" to "uint64" may seem to fit the definition of a backwards-compatible change, but it may not be so for some data encodings that use a fixed binary data chunk (which would grow in size) or even a text format that may use a different encoding for the two types. Specifically, the JSON YANG data format [RFC7951] encodes a "uint32" value as a JSON number but a "uint64" as a JSON string.¶
This section provides several examples of the output from the comparison algorithm defined in this document to illustrate its behavior on actual YANG modules. The example YANG modules are missing “description” or “reference” statements for better readability. Changes are represented as JSON encoded [RFC7951] YANG instance data following the “ietf-yang-schema-comparison-output” module definition in Appendix A for the output.¶
In this example, two new leaves are added to the module.¶
In the generated output, there are changes in both locally resolved module and fully resolved schema. The changes are backward-compatible because the new nodes are added without affecting the order of the existing schema nodes.¶
module mod1 {
namespace "urn:mod1";
prefix m1;
yang-version 1.1;
revision 2025-01-01;
container cont {
leaf l1 {
type string;
}
}
}
¶
module mod1 {
namespace "urn:mod1";
prefix m1;
yang-version 1.1;
revision 2025-06-01;
revision 2025-01-01;
container cont {
leaf l1 {
type string;
}
leaf l2 {
type decimal64 {
fraction-digits 4;
}
}
}
leaf l3 {
type uint8;
}
}
¶
{
"ietf-yang-schema-comparison-output:schema-comparison": {
"schema": [
{
"source": {
"module": "mod1",
"revision": "2025-01-01"
},
"target": {
"module": "mod1",
"revision": "2025-06-01"
},
"conformance": "backwards-compatible",
"node-comparison": [
{
"node": "/mod1:cont/l2",
"node-type": "leaf",
"changed": [
{
"stmt": "node",
"change": "added",
"conformance": "backwards-compatible"
}
],
"new": {
"status": "current",
"config": true,
"mandatory": false,
"type": {
"base-type": "decimal64",
"fraction-digits": 4
}
}
},
{
"node": "/mod1:l3",
"node-type": "leaf",
"changed": [
{
"stmt": "node",
"change": "added",
"conformance": "backwards-compatible"
}
],
"new": {
"status": "current",
"config": true,
"mandatory": false,
"type": {
"base-type": "uint8"
}
}
}
]
}
]
}
}
¶
An example module comparison in which a typedef length restriction is relaxed and a new leaf is added.¶
The generated diff includes both locally resolved and fully resolved changes. In the local comparison, the specific range change is reported as backward-compatible because the restriction was relaxed. In the fully resolved node comparison, the exact same change is reported because the leaf uses the same typedef, whose change also affects the leaf. The newly added leaf is also reported and marked as backward-compatible.¶
module mod1 {
namespace "urn:mod2";
prefix m2;
yang-version 1.1;
revision 2025-01-01;
typedef my-string {
type string {
length "1..10";
}
}
container cont {
leaf l {
type my-string;
}
}
}
¶
module mod1 {
namespace "urn:mod2";
prefix m2;
yang-version 1.1;
revision 2025-06-01;
revision 2025-01-01;
typedef my-string {
type string {
length "1..20";
}
}
container cont {
leaf l {
type my-string;
}
leaf l2 {
type int32;
}
}
}
¶
{
"ietf-yang-schema-comparison-output:schema-comparison": {
"schema": [
{
"source": {
"module": "mod2",
"revision": "2025-01-01"
},
"target": {
"module": "mod2",
"revision": "2025-06-01"
},
"conformance": "backwards-compatible",
"parsed-comparison": [
{
"parent-path": "/",
"identifier": "my-string",
"stmt-type": "typedef",
"changed": [
{
"stmt": "length",
"parent-stmt": "typedef",
"change": "modified",
"conformance": "backwards-compatible"
}
],
"old": {
"type": {
"name": "string",
"length": {
"restriction": "1..10"
}
}
},
"new": {
"type": {
"name": "string",
"length": {
"restriction": "1..20"
}
}
}
}
],
"node-comparison": [
{
"node": "/mod2:cont/l",
"node-type": "leaf",
"changed": [
{
"stmt": "length",
"change": "modified",
"conformance": "backwards-compatible"
}
],
"old": {
"status": "current",
"config": true,
"mandatory": false,
"type": {
"base-type": "string",
"length": {
"interval": [
{
"min": "1",
"max": "10"
}
]
}
}
},
"new": {
"status": "current",
"config": true,
"mandatory": false,
"type": {
"base-type": "string",
"length": {
"interval": [
{
"min": "1",
"max": "20"
}
]
}
}
}
},
{
"node": "/mod2:cont/l2",
"node-type": "leaf",
"changed": [
{
"stmt": "node",
"change": "added",
"conformance": "backwards-compatible"
}
],
"new": {
"status": "current",
"config": true,
"mandatory": false,
"type": {
"base-type": "int32"
}
}
}
]
}
]
}
}
¶