draft-ietf-netconf-yang-notifications-versioning-02.txt

Network Working Group                                            T. Graf
Internet-Draft                                                  Swisscom
Intended status: Standards Track                               B. Claise
Expires: 9 April 2024                                             Huawei
                                                           A. Huang Feng
                                                               INSA-Lyon
                                                          7 October 2023


        Support of Versioning in YANG Notifications Subscription
          draft-ietf-netconf-yang-notifications-versioning-02

Abstract

   This document extends the YANG notifications subscription mechanism
   to specify the YANG module semantic version at the subscription.
   Then, a new extension with the revision and the semantic version of
   the YANG push subscription state change notification is proposed.

Requirements Language

   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.

Status of This Memo

   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 9 April 2024.

Copyright Notice

   Copyright (c) 2023 IETF Trust and the persons identified as the
   document authors.  All rights reserved.



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   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.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Extend the Datastore Selection  . . . . . . . . . . . . . . .   3
   3.  Extend the Subscription State Change Notifications  . . . . .   6
   4.  The "ietf-yang-push-revision" Module  . . . . . . . . . . . .   7
     4.1.  Data Model Overview . . . . . . . . . . . . . . . . . . .   8
     4.2.  YANG Module . . . . . . . . . . . . . . . . . . . . . . .  19
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  25
     5.1.  IETF XML Registry . . . . . . . . . . . . . . . . . . . .  25
     5.2.  YANG Module Name  . . . . . . . . . . . . . . . . . . . .  25
   6.  Operational Considerations  . . . . . . . . . . . . . . . . .  25
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  25
   8.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  26
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  26
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .  26
     9.2.  Informative References  . . . . . . . . . . . . . . . . .  27
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  28

1.  Introduction

   In order to process the newly received YANG push notification
   messages described in section 3.7 of [RFC8641] without querying the
   Publisher IETF-YANG-LIBRARY each time to understand whether the YANG
   module(s) semantic has changed at the YANG push receiver, a semantic
   reference to the YANG module and the XPath or subtree is needed to
   determine the data types for each field and which part of the YANG
   module the metrics are expose from.

   This specification applies to the YANG push configured subscriptions
   defined in Section 2.5 of [RFC8639], where a publisher is configured
   to stream notification out of band, as opposed to dynamic
   subscriptions defined in Section 2.4 of [RFC8639], where the
   subscriber can initiate and modify the subscription dynamically in-
   band.  In the latter case, the subscriber knows already all the
   subscriber YANG-related information, which it has to know in order to
   configure the subscription.





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   This semantic reference is available when the subscription is
   established as described in Section 3.6 of [RFC8641] and being
   streamed from the publisher to receiver with the subscription state
   change notifications described in Section 2.7 of [RFC8639] where for
   each subscription a locally unique subscription ID described in
   Section 4.3.2 of [RFC8641] is being issued and streamed as metadata
   with the notification message in the YANG push message header.

   The semantics can change between different YANG module revisions.
   The YANG module version statement is specified in Section 7.1.2 of
   [RFC6020] and states that the newer revision needs to be backward
   compatible to the previous revision.  Section 3.1 of
   [I-D.ietf-netmod-yang-module-versioning] specifies that newer
   semantic versions introduced in [I-D.ietf-netmod-yang-semver] MAY not
   be backward compatible to the previous version when indicated with
   non-backwards-compatible keyword.

   The YANG notifications subscription mechanism defined in [RFC8641]
   does not allow to specify the YANG module revision.  When a network
   node is upgraded, the subscribed YANG module revision MAY have
   updated and might, consequently, break the data processing pipeline
   since the YANG push receiver may not be aware of this change.

   This documents extends the current YANG notifications subscription
   mechanism to allow to subscribe to a specific revision or latest YANG
   module semantic version to which the YANG module version needs to be
   backward compatible to.  The subscription state change "subscription-
   started" and "subscription-modified" notification messages are also
   extended to include the revision and semantic version.

2.  Extend the Datastore Selection

   The YANG notifications subscription OPTIONALLY can be restricted to
   the following YANG module revision for future capabilities:

   module:
      Restricts the subscription to one or more YANG module names with
      revision and revision-label together for the related streamed
      content.

   revision:
      Restricts the subscription to a specific YANG module revision.
      Example: "2014-05-08".

   revision-label:
      Restricts the subscription to the latest compatible YANG module
      semantic version referenced to.  Example: "2.0.0".




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   When the NETCONF client creates or modifies the subscription using
   the RPCs establish-subscription and modify-subscription and the
   NETCONF server does not support the revision or revision-label
   specified in the RPC request, the NETCONF server MUST return an RPC
   reply including an <rpc-error> element as defined in Section 4.3 of
   [RFC6241] with the error information populated as follows:

   *  an "error-type" node of "application".

   *  an "error-tag" node whose value is a string that corresponds to an
      identity associated with the error.

             +============================+==================+
             | Error identity             | Uses "error-tag" |
             +============================+==================+
             | revision-unsupported       | invalid-value    |
             +----------------------------+------------------+
             | revision-label-unsupported | invalid-value    |
             +----------------------------+------------------+

                    Table 1: General Subscription Error
                 Identities and Associated "error-tag" Use

   Figure 1 provides an example of a "establish-subscription" RPC call
   with YANG revision and datastore-xpath-filter for periodical
   subscription.  Figure 2 shows the response when the RPC has been
   accepted by the NETCONF server and Figure 3 the error sent by the
   NETCONF server when the revision is not supported.























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 <netconf:rpc message-id="101"
     xmlns:netconf="urn:ietf:params:xml:ns:netconf:base:1.0">
   <establish-subscription
       xmlns="urn:ietf:params:xml:ns:yang:ietf-subscribed-notifications"
       xmlns:yp="urn:ietf:params:xml:ns:yang:ietf-yang-push">
       xmlns:ypr="urn:ietf:params:xml:ns:yang:ietf-yang-push-revision">
     <yp:datastore
          xmlns:ds="urn:ietf:params:xml:ns:yang:ietf-datastores">
       ds:operational
     </yp:datastore>
     <yp:datastore-xpath-filter
         xmlns:ex="https://example.com/sample-data/1.0">
       /ex:foo
     </yp:datastore-xpath-filter>
     <ypr:module-version>
       <ypr:module-name>ex:foo</ypr:module-name>
       <ypr:revision>2023-09-17</ypr:revision>
     </ypr:module-version>
     <yp:periodic>
       <yp:period>500</yp:period>
     </yp:periodic>
   </establish-subscription>
 </netconf:rpc>

          Figure 1: RPC Example for an establish-subscription

 <rpc-reply message-id="101"
    xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
    <id
      xmlns="urn:ietf:params:xml:ns:yang:ietf-subscribed-notifications">
       52
    </id>
 </rpc-reply>

  Figure 2: RPC Example for a positive establish-subscription response
















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<rpc-reply message-id="101"
  xmlns="urn:ietf:params:xml:ns:netconf:base:1.0"
  xmlns:yp="urn:ietf:params:xml:ns:yang:ietf-subscribed-notifications">
  <rpc-error>
    <error-type>application</error-type>
    <error-tag>operation-failed</error-tag>
    <error-severity>error</error-severity>
    <error-path xmlns:ypr="urn:ietf:params:xml:ns:yang:ietf-yang-push-revision">
    <error-info>
      <yp:establish-subscription-error-datastore>
        <yp:reason xmlns:ypr="urn:ietf:params:xml:ns:yang:ietf-yang-push-revision">
          ypr:revision-unsupported
        </yp:reason>
      </yp:establish-subscription-error-datastore>
    </error-info>
  </rpc-error>
</rpc-reply>

  Figure 3: RPC Example for an error establish-subscription response

3.  Extend the Subscription State Change Notifications

   Besides the Subscription ID and the xpath or sub-tree filter
   reference as described in Section 2.7 of [RFC8639], the following
   metadata objects are part of a "subscription-started" or
   "subscription-modified" subscription state change notification.

   module:
      Describes the YANG module names for the related streamed content.

   revision:
      Describes the YANG module revision as specified in Section 7.1.9
      of [RFC6020] for the related streamed content.

   revision-label:  Describes the YANG module semantic version as
      specified in [I-D.ietf-netmod-yang-semver] for the related
      streamed content.

   Figure 4 provides an example of a "subscription-modified"
   subscription state change notification message with the YANG module
   name, revision, revision label and datastore-xpath-filter for
   tracking the operational status of a single Ethernet interface (per
   [RFC8343]).  This subscription state change notification message is
   encoded XML [W3C.REC-xml-20081126] over the Network Configuration
   Protocol (NETCONF) as per [RFC8640].






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<notification xmlns="urn:ietf:params:xml:ns:netconf:notification:1.0">
  <eventTime>2023-01-03T10:00:00Z</eventTime>
  <subscription-modified
      xmlns="urn:ietf:params:xml:ns:yang:ietf-subscribed-notifications">
    <id>101</id>
    <stream-xpath-filter
      xmlns:int="urn:ietf:params:xml:ns:yang:ietf-interfaces">
      /int:interfaces
    </stream-xpath-filter>
    <stream>NETCONF</stream>
    <module-version
      xmlns="urn:ietf:params:xml:ns:yang:ietf-yang-push-revision">
      <module-name>ietf-interfaces</module-name>
      <revision>2018-02-20</revision>
      <revision-label>2.0.0</revision-label>
    </module-version>
  </subscription-modified>
</notification>

        Figure 4: XML Push Example for a subscription-modified
                         notification message

   Figure 5 provides an example of a JSON encoded, [RFC8259],
   subscription state change notification message over HTTPS-based
   [I-D.ietf-netconf-https-notif] or UDP-based
   [I-D.ietf-netconf-udp-notif] transport for the same subscription.

   {
     "ietf-restconf:notification" : {
       "eventTime": "2023-01-03T10:00:00Z",
       "ietf-subscribed-notifications:subscription-modified": {
         "id": 101,
         "stream-xpath-filter": "/ietf-interfaces:interfaces",
         "stream": "NETCONF",
         "ietf-yang-push-revision:module-version": [{
           "module-name": "ietf-interfaces"
           "revision": "2018-02-20",
           "revision-label": "2.0.0",
         }],
       }
     }
   }

          Figure 5: JSON Push Example for a subscription-modified
                            notification message

4.  The "ietf-yang-push-revision" Module




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4.1.  Data Model Overview

   This YANG module augments the "ietf-yang-push" module with the
   module-name, revision and revision-label in the "subscription-
   started" and "subscription-modified" subscription state change
   notifications and the ability to define the "revision" and "revision-
   label" in the "establish-subscription" and "modify-subscription" RPCs
   in the datastore push subscription.

4.1.1.  Tree View

   The following is the YANG tree diagram [RFC8340] for the ietf-yang-
   push-revision YANG module

   module: ietf-yang-push-revision

     augment /sn:filters/sn:stream-filter:
       +--rw module-version* [module-name]
          +--rw module-name       yang:yang-identifier
          +--rw revision?         rev:revision-date-or-label
          +--rw revision-label?   ysver:version
     augment /sn:filters/yp:selection-filter:
       +--rw module-version* [module-name]
          +--rw module-name       yang:yang-identifier
          +--rw revision?         rev:revision-date-or-label
          +--rw revision-label?   ysver:version
     augment /sn:establish-subscription/sn:input/sn:target/sn:stream
               /sn:stream-filter/sn:within-subscription:
       +-- module-version* [module-name]
          +-- module-name       yang:yang-identifier
          +-- revision?         rev:revision-date-or-label
          +-- revision-label?   ysver:version
     augment /sn:establish-subscription/sn:input/sn:target/yp:datastore
               /yp:selection-filter/yp:within-subscription:
       +-- module-version* [module-name]
          +-- module-name       yang:yang-identifier
          +-- revision?         rev:revision-date-or-label
          +-- revision-label?   ysver:version
     augment /sn:modify-subscription/sn:input/sn:target/sn:stream
               /sn:stream-filter/sn:within-subscription:
       +-- module-version* [module-name]
          +-- module-name       yang:yang-identifier
          +-- revision?         rev:revision-date-or-label
          +-- revision-label?   ysver:version
     augment /sn:modify-subscription/sn:input/sn:target/yp:datastore
               /yp:selection-filter/yp:within-subscription:
       +-- module-version* [module-name]
          +-- module-name       yang:yang-identifier



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          +-- revision?         rev:revision-date-or-label
          +-- revision-label?   ysver:version
     augment /sn:subscription-started/sn:target/sn:stream
               /sn:stream-filter/sn:within-subscription:
       +--ro module-version* [module-name]
          +--ro module-name       yang:yang-identifier
          +--ro revision          rev:revision-date-or-label
          +--ro revision-label?   ysver:version
     augment /sn:subscription-started/sn:target/yp:datastore
               /yp:selection-filter/yp:within-subscription:
       +--ro module-version* [module-name]
          +--ro module-name       yang:yang-identifier
          +--ro revision          rev:revision-date-or-label
          +--ro revision-label?   ysver:version
     augment /sn:subscription-modified/sn:target/sn:stream
               /sn:stream-filter/sn:within-subscription:
       +--ro module-version* [module-name]
          +--ro module-name       yang:yang-identifier
          +--ro revision          rev:revision-date-or-label
          +--ro revision-label?   ysver:version
     augment /sn:subscription-modified/sn:target/yp:datastore
               /yp:selection-filter/yp:within-subscription:
       +--ro module-version* [module-name]
          +--ro module-name       yang:yang-identifier
          +--ro revision          rev:revision-date-or-label
          +--ro revision-label?   ysver:version
     augment /sn:subscriptions/sn:subscription/sn:target/sn:stream
               /sn:stream-filter/sn:within-subscription:
       +--rw module-version* [module-name]
          +--rw module-name       yang:yang-identifier
          +--rw revision?         rev:revision-date-or-label
          +--rw revision-label?   ysver:version
     augment /sn:subscriptions/sn:subscription/sn:target/yp:datastore
               /yp:selection-filter/yp:within-subscription:
       +--rw module-version* [module-name]
          +--rw module-name       yang:yang-identifier
          +--rw revision?         rev:revision-date-or-label
          +--rw revision-label?   ysver:version

4.1.2.  Full Tree View

   The following is the YANG tree diagram [RFC8340] for the ietf-yang-
   push-revision augmentation within the ietf-subscribed-notifications,
   including the RPCs and notifications.







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  module: ietf-yang-push

    rpcs:
      +---x resync-subscription {on-change}?
         +---w input
            +---w id    sn:subscription-id

    notifications:
      +---n push-update
      |  +--ro id?                   sn:subscription-id
      |  +--ro datastore-contents?   <anydata>
      |  +--ro incomplete-update?    empty
      +---n push-change-update {on-change}?
         +--ro id?                  sn:subscription-id
         +--ro datastore-changes
         |  +--ro yang-patch
         |     +--ro patch-id    string
         |     +--ro comment?    string
         |     +--ro edit* [edit-id]
         |        +--ro edit-id      string
         |        +--ro operation    enumeration
         |        +--ro target       target-resource-offset
         |        +--ro point?       target-resource-offset
         |        +--ro where?       enumeration
         |        +--ro value?       <anydata>
         +--ro incomplete-update?   empty

  module: ietf-subscribed-notifications
    +--ro streams
    |  +--ro stream* [name]
    |     +--ro name                        string
    |     +--ro description?                string
    |     +--ro replay-support?             empty {replay}?
    |     +--ro replay-log-creation-time    yang:date-and-time {replay}?
    |     +--ro replay-log-aged-time?       yang:date-and-time {replay}?
    +--rw filters
    |  +--rw stream-filter* [name]
    |  |  +--rw name                           string
    |  |  +--rw (filter-spec)?
    |  |  |  +--:(stream-subtree-filter)
    |  |  |  |  +--rw stream-subtree-filter?   <anydata> {subtree}?
    |  |  |  +--:(stream-xpath-filter)
    |  |  |     +--rw stream-xpath-filter?     yang:xpath1.0 {xpath}?
    |  |  +--rw ypr:module-version* [module-name]
    |  |     +--rw ypr:module-name       yang:yang-identifier
    |  |     +--rw ypr:revision?         rev:revision-date-or-label
    |  |     +--rw ypr:revision-label?   ysver:version
    |  +--rw yp:selection-filter* [filter-id]



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    |     +--rw yp:filter-id                         string
    |     +--rw (yp:filter-spec)?
    |     |  +--:(yp:datastore-subtree-filter)
    |     |  |  +--rw yp:datastore-subtree-filter?   <anydata>
    |     |  |          {sn:subtree}?
    |     |  +--:(yp:datastore-xpath-filter)
    |     |     +--rw yp:datastore-xpath-filter?     yang:xpath1.0
    |     |             {sn:xpath}?
    |     +--rw ypr:module-version* [module-name]
    |        +--rw ypr:module-name       yang:yang-identifier
    |        +--rw ypr:revision?         rev:revision-date-or-label
    |        +--rw ypr:revision-label?   ysver:version
    +--rw subscriptions
       +--rw subscription* [id]
          +--rw id
          |       subscription-id
          +--rw (target)
          |  +--:(stream)
          |  |  +--rw (stream-filter)?
          |  |  |  +--:(by-reference)
          |  |  |  |  +--rw stream-filter-name
          |  |  |  |          stream-filter-ref
          |  |  |  +--:(within-subscription)
          |  |  |     +--rw (filter-spec)?
          |  |  |     |  +--:(stream-subtree-filter)
          |  |  |     |  |  +--rw stream-subtree-filter?
          |  |  |     |  |          <anydata> {subtree}?
          |  |  |     |  +--:(stream-xpath-filter)
          |  |  |     |     +--rw stream-xpath-filter?
          |  |  |     |             yang:xpath1.0 {xpath}?
          |  |  |     +--rw ypr:module-version* [module-name]
          |  |  |        +--rw ypr:module-name
          |  |  |        |       yang:yang-identifier
          |  |  |        +--rw ypr:revision?
          |  |  |        |       rev:revision-date-or-label
          |  |  |        +--rw ypr:revision-label?   ysver:version
          |  |  +--rw stream
          |  |  |       stream-ref
          |  |  +--ro replay-start-time?
          |  |  |       yang:date-and-time {replay}?
          |  |  +--rw configured-replay?                         empty
          |  |          {configured,replay}?
          |  +--:(yp:datastore)
          |     +--rw yp:datastore
          |     |       identityref
          |     +--rw (yp:selection-filter)?
          |        +--:(yp:by-reference)
          |        |  +--rw yp:selection-filter-ref



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          |        |          selection-filter-ref
          |        +--:(yp:within-subscription)
          |           +--rw (yp:filter-spec)?
          |           |  +--:(yp:datastore-subtree-filter)
          |           |  |  +--rw yp:datastore-subtree-filter?
          |           |  |          <anydata> {sn:subtree}?
          |           |  +--:(yp:datastore-xpath-filter)
          |           |     +--rw yp:datastore-xpath-filter?
          |           |             yang:xpath1.0 {sn:xpath}?
          |           +--rw ypr:module-version* [module-name]
          |              +--rw ypr:module-name
          |              |       yang:yang-identifier
          |              +--rw ypr:revision?
          |              |       rev:revision-date-or-label
          |              +--rw ypr:revision-label?   ysver:version
          +--rw stop-time?
          |       yang:date-and-time
          +--rw dscp?
          |       inet:dscp {dscp}?
          +--rw weighting?                                       uint8
          |       {qos}?
          +--rw dependency?
          |       subscription-id {qos}?
          +--rw transport?
          |       transport {configured}?
          +--rw encoding?
          |       encoding
          +--rw purpose?                                         string
          |       {configured}?
          +--rw (notification-message-origin)? {configured}?
          |  +--:(interface-originated)
          |  |  +--rw source-interface?
          |  |          if:interface-ref {interface-designation}?
          |  +--:(address-originated)
          |     +--rw source-vrf?
          |     |       -> /ni:network-instances/network-instance/name
          |     |       {supports-vrf}?
          |     +--rw source-address?
          |             inet:ip-address-no-zone
          +--ro configured-subscription-state?
          |       enumeration {configured}?
          +--rw receivers
          |  +--rw receiver* [name]
          |     +--rw name                      string
          |     +--ro sent-event-records?
          |     |       yang:zero-based-counter64
          |     +--ro excluded-event-records?
          |     |       yang:zero-based-counter64



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          |     +--ro state                     enumeration
          |     +---x reset {configured}?
          |        +--ro output
          |           +--ro time    yang:date-and-time
          +--rw (yp:update-trigger)?
             +--:(yp:periodic)
             |  +--rw yp:periodic!
             |     +--rw yp:period         centiseconds
             |     +--rw yp:anchor-time?   yang:date-and-time
             +--:(yp:on-change) {on-change}?
                +--rw yp:on-change!
                   +--rw yp:dampening-period?   centiseconds
                   +--rw yp:sync-on-start?      boolean
                   +--rw yp:excluded-change*    change-type

    rpcs:
      +---x establish-subscription
      |  +---w input
      |  |  +---w (target)
      |  |  |  +--:(stream)
      |  |  |  |  +---w (stream-filter)?
      |  |  |  |  |  +--:(by-reference)
      |  |  |  |  |  |  +---w stream-filter-name
      |  |  |  |  |  |          stream-filter-ref
      |  |  |  |  |  +--:(within-subscription)
      |  |  |  |  |     +---w (filter-spec)?
      |  |  |  |  |     |  +--:(stream-subtree-filter)
      |  |  |  |  |     |  |  +---w stream-subtree-filter?
      |  |  |  |  |     |  |          <anydata> {subtree}?
      |  |  |  |  |     |  +--:(stream-xpath-filter)
      |  |  |  |  |     |     +---w stream-xpath-filter?
      |  |  |  |  |     |             yang:xpath1.0 {xpath}?
      |  |  |  |  |     +---w ypr:module-version* [module-name]
      |  |  |  |  |        +---w ypr:module-name
      |  |  |  |  |        |       yang:yang-identifier
      |  |  |  |  |        +---w ypr:revision?
      |  |  |  |  |        |       rev:revision-date-or-label
      |  |  |  |  |        +---w ypr:revision-label?   ysver:version
      |  |  |  |  +---w stream
      |  |  |  |  |       stream-ref
      |  |  |  |  +---w replay-start-time?
      |  |  |  |          yang:date-and-time {replay}?
      |  |  |  +--:(yp:datastore)
      |  |  |     +---w yp:datastore
      |  |  |     |       identityref
      |  |  |     +---w (yp:selection-filter)?
      |  |  |        +--:(yp:by-reference)
      |  |  |        |  +---w yp:selection-filter-ref



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      |  |  |        |          selection-filter-ref
      |  |  |        +--:(yp:within-subscription)
      |  |  |           +---w (yp:filter-spec)?
      |  |  |           |  +--:(yp:datastore-subtree-filter)
      |  |  |           |  |  +---w yp:datastore-subtree-filter?
      |  |  |           |  |          <anydata> {sn:subtree}?
      |  |  |           |  +--:(yp:datastore-xpath-filter)
      |  |  |           |     +---w yp:datastore-xpath-filter?
      |  |  |           |             yang:xpath1.0 {sn:xpath}?
      |  |  |           +---w ypr:module-version* [module-name]
      |  |  |              +---w ypr:module-name
      |  |  |              |       yang:yang-identifier
      |  |  |              +---w ypr:revision?
      |  |  |              |       rev:revision-date-or-label
      |  |  |              +---w ypr:revision-label?   ysver:version
      |  |  +---w stop-time?
      |  |  |       yang:date-and-time
      |  |  +---w dscp?
      |  |  |       inet:dscp {dscp}?
      |  |  +---w weighting?                                       uint8
      |  |  |       {qos}?
      |  |  +---w dependency?
      |  |  |       subscription-id {qos}?
      |  |  +---w encoding?
      |  |  |       encoding
      |  |  +---w (yp:update-trigger)?
      |  |     +--:(yp:periodic)
      |  |     |  +---w yp:periodic!
      |  |     |     +---w yp:period         centiseconds
      |  |     |     +---w yp:anchor-time?   yang:date-and-time
      |  |     +--:(yp:on-change) {on-change}?
      |  |        +---w yp:on-change!
      |  |           +---w yp:dampening-period?   centiseconds
      |  |           +---w yp:sync-on-start?      boolean
      |  |           +---w yp:excluded-change*    change-type
      |  +--ro output
      |     +--ro id                            subscription-id
      |     +--ro replay-start-time-revision?   yang:date-and-time
      |             {replay}?
      +---x modify-subscription
      |  +---w input
      |     +---w id
      |     |       subscription-id
      |     +---w (target)
      |     |  +--:(stream)
      |     |  |  +---w (stream-filter)?
      |     |  |     +--:(by-reference)
      |     |  |     |  +---w stream-filter-name



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      |     |  |     |          stream-filter-ref
      |     |  |     +--:(within-subscription)
      |     |  |        +---w (filter-spec)?
      |     |  |        |  +--:(stream-subtree-filter)
      |     |  |        |  |  +---w stream-subtree-filter?
      |     |  |        |  |          <anydata> {subtree}?
      |     |  |        |  +--:(stream-xpath-filter)
      |     |  |        |     +---w stream-xpath-filter?
      |     |  |        |             yang:xpath1.0 {xpath}?
      |     |  |        +---w ypr:module-version* [module-name]
      |     |  |           +---w ypr:module-name
      |     |  |           |       yang:yang-identifier
      |     |  |           +---w ypr:revision?
      |     |  |           |       rev:revision-date-or-label
      |     |  |           +---w ypr:revision-label?   ysver:version
      |     |  +--:(yp:datastore)
      |     |     +---w yp:datastore
      |     |     |       identityref
      |     |     +---w (yp:selection-filter)?
      |     |        +--:(yp:by-reference)
      |     |        |  +---w yp:selection-filter-ref
      |     |        |          selection-filter-ref
      |     |        +--:(yp:within-subscription)
      |     |           +---w (yp:filter-spec)?
      |     |           |  +--:(yp:datastore-subtree-filter)
      |     |           |  |  +---w yp:datastore-subtree-filter?
      |     |           |  |          <anydata> {sn:subtree}?
      |     |           |  +--:(yp:datastore-xpath-filter)
      |     |           |     +---w yp:datastore-xpath-filter?
      |     |           |             yang:xpath1.0 {sn:xpath}?
      |     |           +---w ypr:module-version* [module-name]
      |     |              +---w ypr:module-name
      |     |              |       yang:yang-identifier
      |     |              +---w ypr:revision?
      |     |              |       rev:revision-date-or-label
      |     |              +---w ypr:revision-label?   ysver:version
      |     +---w stop-time?
      |     |       yang:date-and-time
      |     +---w (yp:update-trigger)?
      |        +--:(yp:periodic)
      |        |  +---w yp:periodic!
      |        |     +---w yp:period         centiseconds
      |        |     +---w yp:anchor-time?   yang:date-and-time
      |        +--:(yp:on-change) {on-change}?
      |           +---w yp:on-change!
      |              +---w yp:dampening-period?   centiseconds
      +---x delete-subscription
      |  +---w input



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      |     +---w id    subscription-id
      +---x kill-subscription
         +---w input
            +---w id    subscription-id

    notifications:
      +---n replay-completed {replay}?
      |  +--ro id    subscription-id
      +---n subscription-completed {configured}?
      |  +--ro id    subscription-id
      +---n subscription-modified
      |  +--ro id
      |  |       subscription-id
      |  +--ro (target)
      |  |  +--:(stream)
      |  |  |  +--ro (stream-filter)?
      |  |  |  |  +--:(by-reference)
      |  |  |  |  |  +--ro stream-filter-name
      |  |  |  |  |          stream-filter-ref
      |  |  |  |  +--:(within-subscription)
      |  |  |  |     +--ro (filter-spec)?
      |  |  |  |     |  +--:(stream-subtree-filter)
      |  |  |  |     |  |  +--ro stream-subtree-filter?
      |  |  |  |     |  |          <anydata> {subtree}?
      |  |  |  |     |  +--:(stream-xpath-filter)
      |  |  |  |     |     +--ro stream-xpath-filter?
      |  |  |  |     |             yang:xpath1.0 {xpath}?
      |  |  |  |     +--ro ypr:module-version* [module-name]
      |  |  |  |        +--ro ypr:module-name       yang:yang-identifier
      |  |  |  |        +--ro ypr:revision
      |  |  |  |        |       rev:revision-date-or-label
      |  |  |  |        +--ro ypr:revision-label?   ysver:version
      |  |  |  +--ro stream
      |  |  |  |       stream-ref
      |  |  |  +--ro replay-start-time?
      |  |  |          yang:date-and-time {replay}?
      |  |  +--:(yp:datastore)
      |  |     +--ro yp:datastore
      |  |     |       identityref
      |  |     +--ro (yp:selection-filter)?
      |  |        +--:(yp:by-reference)
      |  |        |  +--ro yp:selection-filter-ref
      |  |        |          selection-filter-ref
      |  |        +--:(yp:within-subscription)
      |  |           +--ro (yp:filter-spec)?
      |  |           |  +--:(yp:datastore-subtree-filter)
      |  |           |  |  +--ro yp:datastore-subtree-filter?
      |  |           |  |          <anydata> {sn:subtree}?



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      |  |           |  +--:(yp:datastore-xpath-filter)
      |  |           |     +--ro yp:datastore-xpath-filter?
      |  |           |             yang:xpath1.0 {sn:xpath}?
      |  |           +--ro ypr:module-version* [module-name]
      |  |              +--ro ypr:module-name       yang:yang-identifier
      |  |              +--ro ypr:revision
      |  |              |       rev:revision-date-or-label
      |  |              +--ro ypr:revision-label?   ysver:version
      |  +--ro stop-time?
      |  |       yang:date-and-time
      |  +--ro dscp?
      |  |       inet:dscp {dscp}?
      |  +--ro weighting?                                       uint8
      |  |       {qos}?
      |  +--ro dependency?
      |  |       subscription-id {qos}?
      |  +--ro transport?
      |  |       transport {configured}?
      |  +--ro encoding?                                        encoding
      |  +--ro purpose?                                         string
      |  |       {configured}?
      |  +--ro (yp:update-trigger)?
      |     +--:(yp:periodic)
      |     |  +--ro yp:periodic!
      |     |     +--ro yp:period         centiseconds
      |     |     +--ro yp:anchor-time?   yang:date-and-time
      |     +--:(yp:on-change) {on-change}?
      |        +--ro yp:on-change!
      |           +--ro yp:dampening-period?   centiseconds
      |           +--ro yp:sync-on-start?      boolean
      |           +--ro yp:excluded-change*    change-type
      +---n subscription-resumed
      |  +--ro id    subscription-id
      +---n subscription-started {configured}?
      |  +--ro id
      |  |       subscription-id
      |  +--ro (target)
      |  |  +--:(stream)
      |  |  |  +--ro (stream-filter)?
      |  |  |  |  +--:(by-reference)
      |  |  |  |  |  +--ro stream-filter-name
      |  |  |  |  |          stream-filter-ref
      |  |  |  |  +--:(within-subscription)
      |  |  |  |     +--ro (filter-spec)?
      |  |  |  |     |  +--:(stream-subtree-filter)
      |  |  |  |     |  |  +--ro stream-subtree-filter?
      |  |  |  |     |  |          <anydata> {subtree}?
      |  |  |  |     |  +--:(stream-xpath-filter)



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      |  |  |  |     |     +--ro stream-xpath-filter?
      |  |  |  |     |             yang:xpath1.0 {xpath}?
      |  |  |  |     +--ro ypr:module-version* [module-name]
      |  |  |  |        +--ro ypr:module-name       yang:yang-identifier
      |  |  |  |        +--ro ypr:revision
      |  |  |  |        |       rev:revision-date-or-label
      |  |  |  |        +--ro ypr:revision-label?   ysver:version
      |  |  |  +--ro stream
      |  |  |  |       stream-ref
      |  |  |  +--ro replay-start-time?
      |  |  |  |       yang:date-and-time {replay}?
      |  |  |  +--ro replay-previous-event-time?
      |  |  |          yang:date-and-time {replay}?
      |  |  +--:(yp:datastore)
      |  |     +--ro yp:datastore
      |  |     |       identityref
      |  |     +--ro (yp:selection-filter)?
      |  |        +--:(yp:by-reference)
      |  |        |  +--ro yp:selection-filter-ref
      |  |        |          selection-filter-ref
      |  |        +--:(yp:within-subscription)
      |  |           +--ro (yp:filter-spec)?
      |  |           |  +--:(yp:datastore-subtree-filter)
      |  |           |  |  +--ro yp:datastore-subtree-filter?
      |  |           |  |          <anydata> {sn:subtree}?
      |  |           |  +--:(yp:datastore-xpath-filter)
      |  |           |     +--ro yp:datastore-xpath-filter?
      |  |           |             yang:xpath1.0 {sn:xpath}?
      |  |           +--ro ypr:module-version* [module-name]
      |  |              +--ro ypr:module-name       yang:yang-identifier
      |  |              +--ro ypr:revision
      |  |              |       rev:revision-date-or-label
      |  |              +--ro ypr:revision-label?   ysver:version
      |  +--ro stop-time?
      |  |       yang:date-and-time
      |  +--ro dscp?
      |  |       inet:dscp {dscp}?
      |  +--ro weighting?                                       uint8
      |  |       {qos}?
      |  +--ro dependency?
      |  |       subscription-id {qos}?
      |  +--ro transport?
      |  |       transport {configured}?
      |  +--ro encoding?                                        encoding
      |  +--ro purpose?                                         string
      |  |       {configured}?
      |  +--ro (yp:update-trigger)?
      |     +--:(yp:periodic)



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      |     |  +--ro yp:periodic!
      |     |     +--ro yp:period         centiseconds
      |     |     +--ro yp:anchor-time?   yang:date-and-time
      |     +--:(yp:on-change) {on-change}?
      |        +--ro yp:on-change!
      |           +--ro yp:dampening-period?   centiseconds
      |           +--ro yp:sync-on-start?      boolean
      |           +--ro yp:excluded-change*    change-type
      +---n subscription-suspended
      |  +--ro id        subscription-id
      |  +--ro reason    identityref
      +---n subscription-terminated
         +--ro id        subscription-id
         +--ro reason    identityref

4.2.  YANG Module

   The YANG module has two leaves augmenting the model of Subscription
   to YANG Notifications [RFC8639].

   <CODE BEGINS> file "ietf-yang-push-revision@2023-09-17.yang"
   module ietf-yang-push-revision {
     yang-version 1.1;
     namespace
       "urn:ietf:params:xml:ns:yang:ietf-yang-push-revision";
     prefix ypr;
     import ietf-subscribed-notifications {
       prefix sn;
       reference
         "RFC 8639: Subscription to YANG Notifications";
     }
     import ietf-yang-push {
       prefix yp;
       rev:recommended-min "2019-09-09";
       reference
         "RFC 8641: Subscriptions to YANG Datastores";
     }
     import ietf-yang-revisions {
       prefix rev;
       reference
         "RFC XXXX: draft-ietf-netmod-yang-module-versioning-06,
         Updated YANG Module Revision Handling";
     }
     import ietf-yang-types {
       prefix yang;
       rev:recommended-min "2013-07-15";
       reference
         "RFC 6991: Common YANG Data Types.";



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     }
     import ietf-yang-semver {
       prefix ysver;
       reference
         "RFC XXXX: draft-ietf-netmod-yang-semver-08, YANG Semantic
         Versioning";
     }

     organization "IETF NETCONF (Network Configuration) Working Group";
     contact
       "WG Web:   <http:/tools.ietf.org/wg/netconf/>
        WG List:  <mailto:netconf@ietf.org>

        Authors:  Thomas Graf
                  <mailto:thomas.graf@swisscom.com>
                  Benoit Claise
                  <mailto:benoit.claise@huawei.com>
                  Alex Huang Feng
                  <mailto:alex.huang-feng@insa-lyon.fr>";

     description
       "Defines YANG push event notification header with the revision and
       the revision-label. Adds the support of the revision and
       revision-label selection in the YANG push subscription RPCs.

       Copyright (c) 2023 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; see the RFC
       itself for full legal notices.";

     revision 2023-09-17 {
       description
         "First revision";
       reference
         "RFC XXXX: Support of Versioning in YANG Notifications
         Subscription";
     }

     feature yang-push-revision-supported {
       description
         "This feature indicates the YANG Subscription Notifications



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         supports specifying the list of modules, revisions and
         revision-label in the YANG subscription.";
     }

     // Identities
     identity revision-unsupported {
       base sn:establish-subscription-error;
       base sn:modify-subscription-error;
       description
         "Revision not supported.  This failure can be due to subscribing
          to a specific revision not supported by the publisher.";
     }

     identity revision-label-unsupported {
       base sn:establish-subscription-error;
       base sn:modify-subscription-error;
       description
         "Revision-label not supported.  This failure can be due to subscribing
          to a specific revision-label not supported by the publisher.";
     }

     grouping yang-push-module-version-config {
       description
         "This grouping combines the module name, the revision and
         revision-label leaves, with the revision being configurable.";
       leaf module-name {
         type yang:yang-identifier;
         description
           "This references the YANG module name.";
       }
       leaf revision {
         type rev:revision-date-or-label;
         description
           "This references the YANG module revision to be sent in the
           subscription.";
       }
       leaf revision-label {
         type ysver:version;
         description
           "This references the YANG module semversion to be sent in the
           subscription.";
       }
     }

     grouping yang-push-module-version {
       description
         "This grouping combines the module name, the revision and
         revision-label leaves, with the revision being non



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         configurable.";
       leaf module-name {
         type yang:yang-identifier;
         config false;
         mandatory true;
         description
           "This references the YANG module name.";
       }
       leaf revision {
         type rev:revision-date-or-label;
         config false;
         mandatory true;
         description
           "This references the YANG module revision of the sent
           notification message.";
       }
       leaf revision-label {
         type ysver:version;
         description
           "This references the YANG module semversion of the sent
           notification message.";
       }
     }

     grouping yang-push-module-version-list {
       description
         "This grouping defines a list of yang-push-module-version
         grouping.";
       list module-version {
         key "module-name";
         config false;
         description
           "List of yang-push-module-version grouping. The revision is
           not configurable.";
         uses ypr:yang-push-module-version;
       }
     }

     grouping yang-push-module-version-config-list {
       description
         "This grouping defines a list of yang-push-module-version-config
         grouping.";
       list module-version {
         key "module-name";
         description
           "List of yang-push-module-version-config grouping. The revision
           is configurable.";
         uses ypr:yang-push-module-version-config;



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       }
     }

     // Filters
     augment "/sn:filters/sn:stream-filter" {
       description
         "Augment the filters from subscribed notifications with a list
         of yang-push-module-version-config grouping.";
       uses ypr:yang-push-module-version-config-list;
     }
     augment "/sn:filters/yp:selection-filter" {
       description
         "Augment the filters from YANG push with a list of
         yang-push-module-version grouping.";
       uses ypr:yang-push-module-version-config-list;
     }

     // Subscription parameters
     augment "/sn:establish-subscription/sn:input/sn:target/sn:stream"
           + "/sn:stream-filter/sn:within-subscription" {
       description
         "Augment the establish-subscription RPC from the
         ietf-subscribed-notifications YANG module with the
         yang-push-module-version-config-list grouping.";
       uses ypr:yang-push-module-version-config-list;
     }
     augment "/sn:establish-subscription/sn:input/sn:target"
           + "/yp:datastore/yp:selection-filter/yp:within-subscription" {
       description
         "Augment the establish-subscription RPC from the ietf-yang-push
         YANG module with the yang-push-module-version-config-list
         grouping.";
       uses ypr:yang-push-module-version-config-list;
     }
     augment "/sn:modify-subscription/sn:input/sn:target/sn:stream"
           + "/sn:stream-filter/sn:within-subscription" {
       description
         "Augment the modify-subscription RPC from the
         ietf-subscribed-notifications YANG module with the
         yang-push-module-version-config-list grouping.";
       uses ypr:yang-push-module-version-config-list;
     }
     augment "/sn:modify-subscription/sn:input/sn:target/yp:datastore"
           + "/yp:selection-filter/yp:within-subscription" {
       description
         "Augment the modify-subscription RPC from the ietf-yang-push
         YANG module with the yang-push-module-version-config-list
         grouping.";



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       uses ypr:yang-push-module-version-config-list;
     }

     // Subscription notifications
     augment "/sn:subscription-started/sn:target/sn:stream"
           + "/sn:stream-filter/sn:within-subscription" {
       description
         "Augment the subscription-started notification from the
         ietf-subscribed-notifications YANG module with the
         yang-push-module-version-list grouping.";
       uses ypr:yang-push-module-version-list;
     }
     augment "/sn:subscription-started/sn:target/yp:datastore"
           + "/yp:selection-filter/yp:within-subscription" {
       description
         "Augment the subscription-started notification from the
         ietf-yang-push YANG module with the
         yang-push-module-version-list grouping.";
       uses ypr:yang-push-module-version-list;
     }
     augment "/sn:subscription-modified/sn:target/sn:stream"
           + "/sn:stream-filter/sn:within-subscription" {
       description
         "Augment the subscription-modified notification from the
         ietf-subscribed-notifications YANG module with the
         yang-push-module-version-list grouping.";
       uses ypr:yang-push-module-version-list;
     }
     augment "/sn:subscription-modified/sn:target/yp:datastore"
           + "/yp:selection-filter/yp:within-subscription" {
       description
         "Augment the subscription-modified notification from the
         ietf-yang-push YANG module with the
         yang-push-module-version-list grouping.";
       uses ypr:yang-push-module-version-list;
     }

     // Subscription container
     augment "/sn:subscriptions/sn:subscription/sn:target/sn:stream"
           + "/sn:stream-filter/sn:within-subscription" {
       description
         "Augment the subscriptions RPC container from the
         ietf-subscribed-notifications YANG module with the
         yang-push-module-version-config-list grouping.";
       uses ypr:yang-push-module-version-config-list;
     }
     augment "/sn:subscriptions/sn:subscription/sn:target/yp:datastore"
           + "/yp:selection-filter/yp:within-subscription" {



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       description
         "Augment the subscription RPC container from ietf-yang-push
         YANG module with the yang-push-module-version-config-list grouping.";
       uses ypr:yang-push-module-version-config-list;
     }
   }
   <CODE ENDS>

5.  IANA Considerations

5.1.  IETF XML Registry

   This document registers the following URIs in the "IETF XML Registry"
   [RFC3688]:

     URI: urn:ietf:params:xml:ns:yang:ietf-yang-push-revision
     Registrant Contact: The IESG.
     XML: N/A; the requested URI is an XML namespace.

5.2.  YANG Module Name

   This document registers the following YANG modules in the "YANG
   Module Names" registry [RFC6020]:

     name: ietf-yang-push-revision
     namespace: urn:ietf:params:xml:ns:yang:ietf-yang-push-revision
     prefix: ypr
     reference: RFC-to-be

6.  Operational Considerations

   A YANG package [I-D.ietf-netmod-yang-packages], specifies a versioned
   organizational structure used to manage a set of YANG modules that
   collectively defines a package schema.  For example, a YANG package
   could contain a set of YANG modules required to implement a L3VPN
   service on a network node.  It offers therefore a complementary
   information to the solution in this draft by describing how one
   specific YANG module revision is part of a set of YANG modules.

7.  Security Considerations

   The security considerations for the YANG notifications subscription
   mechanism are described in [RFC8641].  This documents adds no
   additional security considerations.







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8.  Acknowledgements

   The authors would like to thank Qiufang Ma and Robert Wilton for
   their review and valuable comments.

9.  References

9.1.  Normative References

   [I-D.ietf-netmod-yang-module-versioning]
              Wilton, R., Rahman, R., Lengyel, B., Clarke, J., and J.
              Sterne, "Updated YANG Module Revision Handling", Work in
              Progress, Internet-Draft, draft-ietf-netmod-yang-module-
              versioning-09, 17 April 2023,
              <https://datatracker.ietf.org/doc/html/draft-ietf-netmod-
              yang-module-versioning-09>.

   [I-D.ietf-netmod-yang-semver]
              Clarke, J., Wilton, R., Rahman, R., Lengyel, B., Sterne,
              J., and B. Claise, "YANG Semantic Versioning", Work in
              Progress, Internet-Draft, draft-ietf-netmod-yang-semver-
              12, 2 October 2023,
              <https://datatracker.ietf.org/doc/html/draft-ietf-netmod-
              yang-semver-12>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC3688]  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
              DOI 10.17487/RFC3688, January 2004,
              <https://www.rfc-editor.org/info/rfc3688>.

   [RFC6020]  Bjorklund, M., Ed., "YANG - A Data Modeling Language for
              the Network Configuration Protocol (NETCONF)", RFC 6020,
              DOI 10.17487/RFC6020, October 2010,
              <https://www.rfc-editor.org/info/rfc6020>.

   [RFC6241]  Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
              and A. Bierman, Ed., "Network Configuration Protocol
              (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
              <https://www.rfc-editor.org/info/rfc6241>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.




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   [RFC8639]  Voit, E., Clemm, A., Gonzalez Prieto, A., Nilsen-Nygaard,
              E., and A. Tripathy, "Subscription to YANG Notifications",
              RFC 8639, DOI 10.17487/RFC8639, September 2019,
              <https://www.rfc-editor.org/info/rfc8639>.

   [RFC8641]  Clemm, A. and E. Voit, "Subscription to YANG Notifications
              for Datastore Updates", RFC 8641, DOI 10.17487/RFC8641,
              September 2019, <https://www.rfc-editor.org/info/rfc8641>.

9.2.  Informative References

   [I-D.ietf-netconf-https-notif]
              Jethanandani, M. and K. Watsen, "An HTTPS-based Transport
              for YANG Notifications", Work in Progress, Internet-Draft,
              draft-ietf-netconf-https-notif-13, 4 November 2022,
              <https://datatracker.ietf.org/doc/html/draft-ietf-netconf-
              https-notif-13>.

   [I-D.ietf-netconf-udp-notif]
              Zheng, G., Zhou, T., Graf, T., Francois, P., Feng, A. H.,
              and P. Lucente, "UDP-based Transport for Configured
              Subscriptions", Work in Progress, Internet-Draft, draft-
              ietf-netconf-udp-notif-10, 7 July 2023,
              <https://datatracker.ietf.org/doc/html/draft-ietf-netconf-
              udp-notif-10>.

   [I-D.ietf-netmod-yang-packages]
              Wilton, R., Rahman, R., Clarke, J., Sterne, J., and B. Wu,
              "YANG Packages", Work in Progress, Internet-Draft, draft-
              ietf-netmod-yang-packages-03, 4 March 2022,
              <https://datatracker.ietf.org/doc/html/draft-ietf-netmod-
              yang-packages-03>.

   [RFC8259]  Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
              Interchange Format", STD 90, RFC 8259,
              DOI 10.17487/RFC8259, December 2017,
              <https://www.rfc-editor.org/info/rfc8259>.

   [RFC8340]  Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams",
              BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018,
              <https://www.rfc-editor.org/info/rfc8340>.

   [RFC8343]  Bjorklund, M., "A YANG Data Model for Interface
              Management", RFC 8343, DOI 10.17487/RFC8343, March 2018,
              <https://www.rfc-editor.org/info/rfc8343>.






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   [RFC8640]  Voit, E., Clemm, A., Gonzalez Prieto, A., Nilsen-Nygaard,
              E., and A. Tripathy, "Dynamic Subscription to YANG Events
              and Datastores over NETCONF", RFC 8640,
              DOI 10.17487/RFC8640, September 2019,
              <https://www.rfc-editor.org/info/rfc8640>.

   [W3C.REC-xml-20081126]
              Bray, T., Paoli, J., Sperberg-McQueen, M., Maler, E., and
              F. Yergeau, "Extensible Markup Language (XML) 1.0 (Fifth
              Edition)", World Wide Web Consortium Recommendation REC-
              xml-20081126, November 2008,
              <https://www.w3.org/TR/2008/REC-xml-20081126>.

Authors' Addresses

   Thomas Graf
   Swisscom
   Binzring 17
   CH-8045 Zurich
   Switzerland
   Email: thomas.graf@swisscom.com


   Benoit Claise
   Huawei
   Email: benoit.claise@huawei.com


   Alex Huang Feng
   INSA-Lyon
   Lyon
   France
   Email: alex.huang-feng@insa-lyon.fr


















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