



Network Working Group                                      A. Huang-Feng
Internet-Draft                                               P. Francois
Intended status: Standards Track                               INSA-Lyon
Expires: 19 December 2025                                        T. Graf
                                                                Swisscom
                                                               B. Claise
                                                                  Huawei
                                                            17 June 2025


           Extensible YANG Model for YANG-Push Notifications
                  draft-ietf-netconf-notif-envelope-02

Abstract

   This document defines a new extensible notification structure,
   defined in YANG, for use in YANG-Push Notification messages enabling
   any YANG-compatible encodings such as XML, JSON, or CBOR.
   Additionally, it defines two essential extensions to this structure,
   the support of a hostname and a sequence number and the support of a
   timestamp characterizing the moment when the changed data was
   observed.

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 19 December 2025.

Copyright Notice

   Copyright (c) 2025 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.



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   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  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   4
   2.  Relationship to past documents  . . . . . . . . . . . . . . .   4
     2.1.  Relationship to RFC5277 . . . . . . . . . . . . . . . . .   4
     2.2.  Relationship to RFC8639 . . . . . . . . . . . . . . . . .   5
     2.3.  Relationship to RFC7950 . . . . . . . . . . . . . . . . .   5
     2.4.  Relationship to RFC7951 . . . . . . . . . . . . . . . . .   5
     2.5.  Relationship to RFC9254 . . . . . . . . . . . . . . . . .   5
   3.  Solution  . . . . . . . . . . . . . . . . . . . . . . . . . .   6
     3.1.  Enabling the Notification Envelope  . . . . . . . . . . .   7
     3.2.  Discovering the support of this model . . . . . . . . . .   7
     3.3.  Notification Envelope . . . . . . . . . . . . . . . . . .   8
       3.3.1.  Base Notification Model . . . . . . . . . . . . . . .   8
       3.3.2.  Encoding of the Notification Model  . . . . . . . . .   8
     3.4.  Extensions for the Notification Envelope  . . . . . . . .  14
       3.4.1.  Support of Hostname and Sequencing  . . . . . . . . .  15
     3.5.  Extensions for the YANG-Push Header . . . . . . . . . . .  17
       3.5.1.  Support of Observation Timestamp  . . . . . . . . . .  18
   4.  Operational Considerations  . . . . . . . . . . . . . . . . .  24
   5.  YANG Modules  . . . . . . . . . . . . . . . . . . . . . . . .  24
     5.1.  The 'ietf-yp-notification' Module . . . . . . . . . . . .  24
       5.1.1.  YANG ietf-yp-notification Tree Diagram  . . . . . . .  25
       5.1.2.  YANG ietf-yp-notification Module  . . . . . . . . . .  25
     5.2.  The 'ietf-yp-observation' Module  . . . . . . . . . . . .  29
       5.2.1.  YANG ietf-yp-observation Tree Diagram . . . . . . . .  29
       5.2.2.  YANG ietf-yp-observation Module . . . . . . . . . . .  29
   6.  Implementation Status . . . . . . . . . . . . . . . . . . . .  32
     6.1.  Huawei VRP  . . . . . . . . . . . . . . . . . . . . . . .  33
     6.2.  6WIND VSR . . . . . . . . . . . . . . . . . . . . . . . .  33
     6.3.  Cisco IOS XR  . . . . . . . . . . . . . . . . . . . . . .  33
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  33
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  34
     8.1.  URI . . . . . . . . . . . . . . . . . . . . . . . . . . .  34
     8.2.  YANG module name  . . . . . . . . . . . . . . . . . . . .  34
     8.3.  YANG SID-file . . . . . . . . . . . . . . . . . . . . . .  34
   9.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  35
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .  35
     10.1.  Normative References . . . . . . . . . . . . . . . . . .  35
     10.2.  Informative References . . . . . . . . . . . . . . . . .  37
   Appendix A.  .sid file  . . . . . . . . . . . . . . . . . . . . .  38



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   Appendix B.  Example extending the Notification Envelope  . . . .  42
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  43

1.  Introduction

   YANG-Push [RFC8639] allows publishers to send notifications to a data
   collection.  The YANG-Push receiver decodes the message and
   optionally validates the header and the content before forwarding to
   the next process in the data collection system.

   The notification container from YANG-Push is currently based on the
   XML model from NETCONF Event Notifications [RFC5277].  This model has
   the drawback that only a single mandatory "eventTime" leaf is defined
   and does not offer a way to extend this header with new notification
   metadata.  Additionally, this XML model is only valid for XML-based
   environments.  When messages are encoded in other YANG encodings,
   such as JSON [RFC7951] or CBOR [RFC9254], validators cannot use YANG
   to validate the message schema.

   YANG data consumers receiving notifications require additional
   notification metadata to understand the full context of the received
   message.  For example, in addition to the timestamp of when the event
   was encoded, it is also important to know the timestamp when the
   metrics were observed, the hostname that sourced the message, and
   have sequence numbers in generated messages so that lost notification
   messages can be detected in unreliable transports.  This additional
   notification metadata is also helpful in correlating the data with
   other sources of Network Telemetry [RFC9232] information.

   For such reasons, this document proposes the following:

   *  First, it provides an extensible YANG notification header allowing
      implementors and IETF contributors to easily add new notification
      metadata to the notification message.

   *  Second, it provides the first crucial extensions enabling
      operators to identify which network node publishes which YANG-Push
      messages and when the events or metrics were observed on the
      network node.

   *  And finally, it provides a way to enable and disable these
      extensions globally at the server, making the coexistence of
      different YANG-Push and NETCONF Event Notification [RFC5277]
      possible.







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1.1.  Terminology

   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.

   The terms "subscriber", "publisher", and "receiver" are used as
   defined in [RFC8639].

   The term "client" is used as defined in [RFC6241] for NETCONF and
   [RFC8040] for RESTCONF.

   The terms "implementation-time information" and "runtime information"
   are used as defined in [RFC9196].

   In addition, this document defines the following terms:

   Notification Metadata: Additional data describing the context of a
   notification that is sent in each message, e.g. which node generated
   the messsage or at which time the notification was published.

   Notification Envelope: YANG structure encapsulating the payload of a
   notification, allowing the inclusion of metadata.

2.  Relationship to past documents

   This section shows the relationship to [RFC5277], [RFC8639],
   [RFC7951] and [RFC9254].

2.1.  Relationship to RFC5277

   [RFC5277] defines a mechanism for NETCONF nodes to send notifications
   to a collector.  These are the key relationships between the current
   document and [RFC5277]:

   *  This document does not change the header defined by [RFC5277] nor
      update any behavior defined in [RFC5277].  Implementations of
      [RFC5277] use the header defined in Section 2.2.1 of [RFC5277].

   *  The co-existence of the notification model defined in [RFC5277]
      and the model defined in the current document is possible.  The
      co-existence is discussed in Section 4.







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2.2.  Relationship to RFC8639

   Subscribed Notifications [RFC8639] defines a mechanism on top of
   [RFC5277] to stream notifications from the NETCONF node.  These are
   the key relationships between the current document and [RFC8639]:

   *  Section 1.4 of [RFC8639] states that the solution uses the
      notification header defined in [RFC5277].  This document proposes
      a new header, which clients can enable and replace the previously
      [RFC5277] defined.  When this new header is used, notification
      messages are encoded as defined in Section 3.3.

   *  Section 2.4.2 of [RFC8639] defines how a YANG-Push subscription is
      defined via a 'establish-subscription' RPC.  This document extends
      the RPCs from Subscribed Notifications [RFC8639] to support
      enabling the new header defined in this document.

2.3.  Relationship to RFC7950

   [RFC7950] defines how YANG data is encoded in XML.  These are the key
   relationship points between the current document and [RFC7950]:

   *  Section 7.16.2 of [RFC7950] defines the XML encoding of YANG
      notification.  This document defines a new header for such
      notifications.  When a YANG-Push publisher implements the
      specifications in this document with the XML encoding, the
      notifications are encoded according to Section 3.3.2.1.

2.4.  Relationship to RFC7951

   [RFC7951] defines how YANG data is encoded using JSON.  These are the
   key relationship points between the current document and [RFC7951]:

   *  [RFC7951] does not define explicitly how a YANG notification
      should be encoded using JSON encoding.  This document specifies a
      new header for such notifications.  When a YANG-Push publisher
      implements the specifications in this document with JSON encoding,
      the notifications are encoded according to Section 3.3.2.2.

2.5.  Relationship to RFC9254

   [RFC9254] defines how YANG data is encoded using CBOR.  These are the
   key relationship points between the current document and [RFC9254]:








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   *  [RFC9254] does not define explicitly how a YANG notification
      should be encoded using CBOR encoding.  When a YANG-Push publisher
      implements the specifications in this document in CBOR encoding,
      the notifications are encoded according to Section 3.3.2.3 in this
      document.

3.  Solution

   Section 4.2.10 of [RFC7950] defines the encoding of YANG
   notifications.  A notification is created by defining a
   'notification' statement in the YANG module.  When a NETCONF server
   sends this notification, it comprises two parts: a header containing
   notification metadata that encapsulates the content and the content
   defined by the 'notification' statement.

   In YANG 1.1 [RFC7950], the notification header is based on the model
   defined in [RFC5277] which contains a single metadata 'eventTime'
   leaf.  An example extracted from [RFC7950] is shown in the following
   XML:

     <notification
         xmlns="urn:ietf:params:netconf:capability:notification:1.0">
       <eventTime>2007-09-01T10:00:00Z</eventTime>
       <link-failure xmlns="urn:example:system">
         <if-name>so-1/2/3.0</if-name>
         <if-admin-status>up</if-admin-status>
         <if-oper-status>down</if-oper-status>
       </link-failure>
     </notification>

   This document defines a new notification header and enables extending
   this header with new notification metadata.  The notification header
   and extensions defined in the following sections are to be used in
   YANG-Push [RFC8641] environments and can be implemented with NETCONF
   [RFC6241] and RESTCONF [RFC8040].  Thus, when enabled, this new
   header replaces the notifications defined in Subscribed Notifications
   [RFC8639] and YANG-Push [RFC8641] notifications globally for all the
   entire server.

   Section 3.1 defines how a client enables the header defined in this
   document.  Section 3.2 extends the model from [RFC9196] to enable
   clients to discover the capability of using the new notification
   header for both implementation-time and runtime information.  Lastly,
   Section 3.3.2 defines the new notification header and how it is
   encoded using XML, JSON, and CBOR.






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3.1.  Enabling the Notification Envelope

   The notification envelope defined in this document can be enabled
   during the configuration of a YANG-Push subscription.  This document
   augments the "ietf-subscribed-notification" model [RFC8639] to
   support the configuration of the "notification-envelope".  When
   enabled, all the notifications defined in Subscribed Notification
   [RFC8639] and YANG-Push [RFC8641] are encoded as defined in
   Section 3.3.

   module: ietf-yp-notification

     augment /sn:subscriptions:
       +--rw enable-notification-envelope?   boolean
       +--rw metadata

   When the node 'enable-notification-envelope' is set to true, the
   notifications published by a YANG-Push publisher MUST use the header
   defined in Section 3.3.1.  If any notification metadata is enabled
   during the subcription configuration, the notification metadata nodes
   MUST be present in the header.  When this node is disabled,
   notifications are encoded as defined in NETCONF Event Notifications
   [RFC5277].

   When there are existing subscriptions and a client changes the node
   'enable-notification-envelope', all existing subscriptions MUST be
   terminated.  The publisher MUST send a 'subscription-terminated'
   notification to all the existing subscriptions using the header
   configured before the change.  Any new subscription after the change
   use the header defined by the node 'enable-notification-envelope',
   i.e. encoded as Section 3.3.1 when enabled and as defined in
   [RFC5277] if disabled.

3.2.  Discovering the support of this model

   A client can discover the support of 'notification-envelope' model
   through the capabilities model defined in [RFC9196].  This documents
   extends the 'ietf-notification-capabilities' model with:

   *  A container containing a leaf 'notification-envelope', stating
      that the YANG notification can be encoded following the
      notification-envelope model.

   *  A container 'metadata' containing all the supported extensions to
      this header.  Extensions are defined in Section 3.4.

   The YANG models defined in Section 5 augments the 'ietf-notification-
   capabilities' model with the leaf and container listed above:



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     augment /sysc:system-capabilities/notc:subscription-capabilities:
       +--ro notification-metadata
          +--ro notification-envelope?   boolean
          +--ro metadata

   This model can be retrieved via a NETCONF <get> RPC.

3.3.  Notification Envelope

   This section defines how YANG notifications are structured when the
   notification envelope is enabled on YANG-Push subscriptions.  The
   following sections define how this model is encoded in XML, JSON and
   CBOR.

3.3.1.  Base Notification Model

   When a YANG-Push publisher uses the notification model defined in
   this document, the notification is structured as follows:

   *  The notification is encapsulated in a root "envelope" container.

   *  The header of the notification contains the notification metadata
      that is enabled during the configuration of the subscription as a
      child nodes of the root "notification-envelope" container.

   *  The content of the notification defined by the 'notification'
      statement is encoded in the 'contents' leaf.

   *  The 'contents' element MUST be located at the end of the
      notification envelop structure.

   The following YANG tree [RFC8340] illustrates the notification
   envelope supporting only the mandatory metadata 'event-time'.  See
   Section 3.4 for more extensions to this header.

     structure envelope:
       +-- event-time         yang:date-and-time
       +-- contents?          <anydata>

3.3.2.  Encoding of the Notification Model

   The YANG notification can be encoded using XML
   [W3C.REC-xml-20001006][RFC7951], JSON [RFC7951] and CBOR [RFC9254].








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3.3.2.1.  XML encoding

   A YANG notification encoded in XML is structured as a root "envelope"
   container.  The namespace of this container is the namespace defined
   in the YANG module "ietf-yp-notification":

       urn:ietf:params:xml:ns:yang:ietf-yp-notification

   Two mandatory child nodes within the "envelope" container are
   expected, representing the event time and the notification payload.
   The "event-time" node is defined within the same XML namespace as the
   "envelope" container.  The "event-time" node MUST be compliant with
   [RFC3339].  Other notification metadata within the YANG module
   defined in Section 5.1.2 MUST use the same XML namespace.  See
   Section 3.4 for more details.

   When other notification metadata is enabled through configuration,
   the supplementary nodes are encoded at the same level as the
   mandatory "event-time" node and use the XML namespace defined in the
   YANG module.

   The content of the notification that is defined by the 'notification'
   statement is encoded in the "contents" node.  The name and namespace
   of this payload element are determined by the YANG module containing
   the 'notification' statement representing the notification message.

   The following example shows a "push-update" notification defined in
   the YANG module of YANG-Push [RFC8641] encoded in XML:























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   <envelope xmlns="urn:ietf:params:xml:ns:yang:ietf-yp-notification">
     <event-time>2024-10-10T10:59:55.32Z</event-time>
     <contents>
       <push-update xmlns="urn:ietf:params:xml:ns:yang:ietf-yang-push">
         <id>1011</id>
         <datastore-contents>
           <interfaces
             xmlns="urn:ietf:params:xml:ns:yang:ietf-interfaces">
             <interface>
               <name>eth0</name>
               <type>iana-if-type:ethernetCsmacd</type>
               <if-index>1</if-index>
               <admin-status>down</admin-status>
               <oper-status>down</oper-status>
               <statistics>
                 <discontinuity-time>
                   2013-04-01T03:00:00+00:00
                 </discontinuity-time>
               </statistics>
            </interface>
           </interfaces>
         </datastore-contents>
       </push-update>
     </contents>
   </envelope>

                     Figure 1: XML-encoded notification

3.3.2.2.  JSON Encoding

   A YANG notification encoded in JSON is structured as a root
   "envelope" container.  The namespace of this container is the name of
   the YANG module "ietf-yp-notification" defined in Section 5.1.2.

   Two mandatory child nodes within the "ietf-notification:envelope"
   container are expected, representing the event time and the
   notification payload.  The "event-time" node is defined within the
   same namespace as the "ietf-yp-notification:envelope" container and
   is compliant with [RFC3339].  Other metadata specified within the
   YANG module defined in Section 5.1.2 MUST use the same namespace
   "ietf-yp-notification".

   When other notification metadata is enabled through configuration,
   the supplementary nodes are encoded at the same level as the
   mandatory 'event-time' node and use the YANG module name as its
   namespace.  See Section 3.4 for more details.





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   The content of the notification that is defined by the 'notification'
   statement is encoded in the "contents" node.  The name and namespace
   of this payload element are determined by the YANG module containing
   the 'notification' statement representing the notification message.

   The following example shows a "push-update" notification defined in
   the YANG module of YANG-Push [RFC8641] encoded in JSON:

     {
       "ietf-yp-notification:envelope": {
         "event-time": "2024-10-10T08:00:11.22Z",
         "contents": {
           "ietf-yang-push:push-update": {
             "id": 1011,
             "datastore-contents": {
               "ietf-interfaces:interfaces": {
                 "interface": [
                   {
                     "name": "eth0",
                     "type": "iana-if-type:ethernetCsmacd",
                     "if-index": 1,
                     "admin-status": "up",
                     "oper-status": "up",
                     "statistics": {
                       "discontinuity-time": "2025-03-25T06:43:12Z"
                     }
                   }
                 ]
               }
             }
           }
         }
       }
     }

                    Figure 2: JSON-encoded notification

3.3.2.3.  CBOR Encoding

   YANG notifications can be encoded in CBOR using Names or SIDs in
   keys.

   Notifications encoded using names is similar to JSON encoding as
   defined in Section 3.3 of [RFC9254].  The key of the element can be
   the name of the element itself or be namespace-qualified.  In the
   latter case, the namespace of the notification container uses the
   YANG module name "ietf-yp-notification", defined in Section 5.1.2.




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   Notification encoded using YANG-SIDs replaces the names of the keys
   of the CBOR encoded message for a 63-bit unsigned integer.  In this
   case, the keys of the encoded data use the SID value as defined in
   Section 3.2 of [RFC9254].  A SID allocation process is needed
   beforehand as defined in [RFC9595].

   In the notification, two mandatory child nodes within the "ietf-yp-
   notification:envelope" container are expected, representing the event
   time and the notification payload.  The "event-time" node is defined
   within the same namespace as the "ietf-yp-notification:envelope"
   container and is compliant with [RFC3339].

   When other notification metadata is enabled through configuration,
   the supplementary nodes are encoded at the same level as the
   mandatory "event-time" node and use the YANG module name as its
   namespace when they are encoded as names.  When encoded using YANG
   SIDs, a SID value assigned to the metadata node is used.  See
   Section 3.4 for more details.

   The content of the notification that is defined by the 'notification'
   statement is encoded in the "contents" node.  The name and namespace
   of this payload element are determined by the YANG module containing
   the 'notification' statement representing the notification message.
   Similarly, SIDs can be used as keys if they are well allocated.

   Figure 3 shows a "push-update" notification defined in the YANG
   module of YANG-Push [RFC8641] encoded in CBOR using names as keys.
   The example uses the CBOR diagnostic notation as defined in section
   3.1 of [RFC9254]:






















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     {
       "ietf-yp-notification:envelope": {
         "event-time": "2024-10-10T08:00:11.22Z",
         "contents": {
           "ietf-yang-push:push-update": {
             "id": 1011,
             "datastore-contents": {
               "ietf-interfaces:interfaces": {
                 "interface": [
                   {
                     "name": "eth0",
                     "type": "iana-if-type:ethernetCsmacd",
                     "if-index": 1,
                     "admin-status": "up",
                     "oper-status": "up",
                     "statistics": {
                       "discontinuity-time": "2025-03-25T06:43:12Z"
                     }
                   }
                 ]
               }
             }
           }
         }
       }
     }

       Figure 3: CBOR-encoded notification using diagnostic notation

   And Figure 4 shows the same notification encoded using SIDs:





















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     {
       2958: {
         2: "2024-10-10T08:00:11.22Z",
         1: {
           "ietf-yang-push:push-update": {
             "id": 1011,
             "datastore-contents": {
               "ietf-interfaces:interfaces": {
                 "interface": [
                   {
                     "name": "eth0",
                     "type": "iana-if-type:ethernetCsmacd",
                     "if-index": 1,
                     "admin-status": "up",
                     "oper-status": "up",
                     "statistics": {
                       "discontinuity-time": "2025-03-25T06:43:12Z"
                     }
                   }
                 ]
               }
             }
           }
         }
       }
     }

        Figure 4: CBOR-encoded notification using YANG SIDs in CBOR
                            diagnostic notation

3.4.  Extensions for the Notification Envelope

   This section describes two envelope header extensions.  When the
   envelope is enabled via the "enable-notification-envelope" node, the
   publisher includes by default the "hostname" and "sequence-number"
   defined in Section 3.4.1.  The client discovers the support of these
   two extensions with the mechanism defined in Section 3.2.  When the
   extensions defined in this document are supported by the server, the
   client discovers the presence of new metadata with the following
   augmentations in the 'ietf-notification-capabilities':











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   module: ietf-yp-notification

     augment /sysc:system-capabilities/notc:subscription-capabilities:
       +--ro notification-metadata
          +--ro notification-envelope?   boolean
          +--ro metadata
             +--ro hostname-sequence-number?   boolean

   module: ietf-yp-observation

     augment /sysc:system-capabilities/notc:subscription-capabilities:
       +--ro yang-push-observation-supported?   boolean
               {yang-push-observation-timestamp}?

   This document defines the following notification metadata as shown in
   the following YANG tree [RFC8340].  It also defines an extension to
   the YANG-Push header.  See the following sections for more details.

     structure envelope:
       +-- event-time         yang:date-and-time
       +-- hostname?          inet:host
       +-- sequence-number?   yang:counter32
       +-- contents?          <anydata>

3.4.1.  Support of Hostname and Sequencing

   When YANG-Push notification messages are forwarded from a receiver to
   another system, such as a message broker or a time series database,
   the transport context is lost since it is not part of the
   notification metadata of the notification container.  Therefore, the
   downstream system is unable to associate the message with the
   publishing process (the exporting network node), nor able to detect
   message loss or reordering.

   To correlate network data among different Network Telemetry planes as
   described in Section 3.1 of [RFC9232] or among different YANG-Push
   subscription types as defined in Section 3.1 of [RFC8641], a
   reference to the node streaming the data is needed.  This is
   essential for understanding the timely relationship among these
   different planes and YANG-Push subscription types.

   Today, network operators work around this impediment by preserving
   the transport source IP address and sequence numbers of the
   publishing process.  However, this implies encoding this information
   in the YANG-Push notification messages which impact the semantic
   readability of the message in the downstream system.





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   On top of that, the transport source IP address might not represent
   the management IP address by which the YANG-Push publisher should be
   known.  In other terms, the "source-host" [RFC6470], which is the
   "Address of the remote host for the session" might not be the
   management IP address.

   To overcome these issues, this document proposes a notification
   container extension with a hostname and a sequence number.  This
   allows the downstream system to not only be able to identify from
   which network node, subscription, and time the message was published
   but also, the order of the published messages.

   hostname:  Describes the node's hostname according to the 'sysName'
      object definition in [RFC1213] from where the message was
      published from.  This value is usually configured on the node by
      the administrator to identify the node in the network uniquely.

   sequence-number:  Generates a unique sequence number for each
      published message by the publisher process.  The number counts up
      at every published notification message as described in [RFC9187].

   Figure 5 provides an example of a JSON encoded, [RFC8259], "push-
   update" notification message with hostname and sequence-number as
   extension.



























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   {
       "ietf-yp-notification:envelope": {
       "event-time": "2023-03-25T08:30:11.22Z",
       "hostname": "example-router",
       "sequence-number": 1,
       "contents": {
         "ietf-yang-push:push-update": {
           "id": 6666,
           "datastore-contents": {
             "ietf-interfaces:interfaces": {
               "interface": [
                 {
                   "name": "eth0",
                   "type": "iana-if-type:ethernetCsmacd",
                   "if-index": 1,
                   "admin-status": "up",
                   "oper-status": "up",
                   "statistics": {
                     "discontinuity-time": "2025-03-25T06:43:12Z"
                   }
                 }
               ]
             }
           }
         }
       }
     }
   }

      Figure 5: JSON Example for a 'push-update' notification message

3.5.  Extensions for the YANG-Push Header

   This section described two optional YANG 'push-update' and 'push-
   change-update' notification header extensions which are enabled by
   default.  The client discovers the support of these two extension
   headers with the mechanism defined in Section 3.2.

   This document defines the following notification metadata as shown in
   the following YANG tree [RFC8340].  See the following sections for
   more details.










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   module: ietf-yp-observation

     augment /yp:push-update:
       +--ro timestamp?       yang:date-and-time
       +--ro point-in-time?   enumeration
     augment /yp:push-change-update:
       +--ro timestamp?       yang:date-and-time
       +--ro point-in-time?   enumeration

3.5.1.  Support of Observation Timestamp

   To correlate network data among different Network Telemetry planes,
   as described in Section 3.1 of [RFC9232], or among different YANG-
   Push subscription types, as defined in Section 3.1 of [RFC8641], a
   receiver needs a timestamp reference to align all the metrics and
   events.  The observation timestamp defined in this document
   characterizes the moment the state change was observed or the moment
   when the data was measured, so that a receiver can correctly align
   the collected data.

   The delay between the YANG-Push export process and the reception of
   the message at the receiver instance can be measured using the node
   'event-time' defined in Section 3.3.1.  However, as the 'event-time'
   node only establishes the moment when the YANG-Push message was
   crafted and sent, the moment when such metrics were collected or the
   state changes were observed cannot be measured using this timestamp.
   The observation timestamp defined in this section characterizes the
   moment when the metrics were observed, which enable aligning the
   received metrics to the actual moment they were measured.

   When the time bucket length in a time series database and the
   periodical YANG-Push subscription time are configured with the same
   values, the 'event-time' of the NETCONF notification message header
   can be used for indexing the data in the time series database.  There
   is a variable delay between the observation timestamp, the 'event-
   time', and the "anchor-time" as described in Section 4.2 of
   [RFC8641].  When these timestamps are close to the time bucket
   boundaries, a time bucket may experience data collection
   discrepancies, e.g. 0 measurements are aggregated into one time
   bucket while the next time bucket contains 2 measurements.  This
   leads to inconsistent accounting errors in the time series database.
   This problem is resolved using the observation timestamp instead of
   the 'event-time' for time series database indexation.

   By extending YANG-Push Notifications with the observation timestamp
   and a 'point-in-time' node, the data collection process can always
   ensure it has the best available time for indexing the data.  It can
   therefore use unconditionally the observation timestamp node in the



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   data processing chain to correctly align the metrics and events.  At
   the same time, the 'point-in-time' node ensures that the semantics
   associated with the timestamp are not lost throughout the data
   collection chain.

   Besides the Subscription ID as described in Section 3.7 of [RFC8641],
   the following network observation time metadata objects are part of
   "push-update" and "push-change-update" notifications.

   timestamp:  States the measurement observation time for the "push-
      update" notification in "periodical" subscriptions and for the
      "push-change-update" notification in "on-change" subscriptions.

      By comparing the observation timestamp of two "push-update"
      notifications in a periodical subscription, the collector can
      deduce the actual cadence of the measurements, and compare it with
      the subscription configuration.  In case of an "on-change"
      subscription it states the time when the network state change was
      observed.

   point-in-time:  The enumeration states at which point in time the
      value of the observation timestamp was observed.  Choices are:

      'current-accounting' states the point in time where the metrics
      are polled and observed in "periodical" subscriptions.

      'initial-state' states the initial point in time when the
      subscription was established and the state was observed for "on-
      change sync on start" subscriptions.

      'state-changed' states the point in time when the state change was
      observed after the subscription was established for "on-change"
      and "on-change sync on start" subscriptions.

3.5.1.1.  Usage Example

   This section illustrates the usage of the "point-in-time" node in two
   different subscriptions.  Section 3.5.1.1.1 showcases a YANG-Push
   subscription monitoring the state of an interface using an 'on-change
   sync on start' subscription.  Section 3.5.1.1.2 illustrates the usage
   of the 'point-in-time' node within periodical subscriptions.

3.5.1.1.1.  On-Change Subscriptions

   Figure 6 illustrates the set of events that lead to the generation of
   'on-change' YANG-Push notifications.  This timeline depicts the
   following states and events:




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   *  T1: At first, the operational state of the interface is "Up".

   *  T2: After configuring an 'on-change' subscription supporting 'sync
      on start', the publisher sends the initial state of the interface.

   *  T3: This is the moment the interface changes its operational
      status to "Down".

   *  T4: After the interface state changes, the publisher generates the
      'on-change' notification alerting the receiver.

Timeline
---------------------------------------------------------------------->
 | (T1) Interface | (T2) YANG-Push   | (T3) Interface | (T4) YANG-Push
 | state changed  | "on-change sync  | state changed  | "on-change"
 | to "Up".       | on start"        | to "Down".     | notification
 |                | subscription for |                | with the new
 |                | interface state  |                | interface state.
 |                | is established.  |                |
 v                v                  v                v

 Figure 6: Example timeline for On-Change Sync on Start Subscription

   At T2, after configuring the subscription, the publisher triggers a
   'push-update' notification as depicted in Figure 7.  The 'event-time'
   is the moment the YANG-Push process triggered the notification while
   the 'ietf-yp-observation:timestamp' node characterizes the timestamp
   T1, the latest moment this state was observed.  In this case, the
   'point-in-time' node is set to 'initial-state'.






















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   {
     "ietf-yp-notification:envelope": {
       "event-time": "2025-03-25T08:30:11.22Z",
       "hostname": "example-router",
       "sequence-number": 1,
       "contents": {
         "ietf-yang-push:push-update": {
           "id": 6666,
           "ietf-yp-observation:timestamp": "2025-03-25T08:29:30.22Z",
           "ietf-yp-observation:point-in-time": "initial-state",
           "datastore-contents": {
             "ietf-interfaces:interfaces": {
               "interface": [{
                 "name": "eth0",
                 "type": "iana-if-type:ethernetCsmacd",
                 "if-index": 1,
                 "admin-status": "up",
                 "oper-status": "up",
                 "statistics": {
                   "discontinuity-time": "2025-03-25T06:43:12Z"
                 }
               }]
             }
           }
         }
       }
     }
   }

       Figure 7: Example of 'push-update' notification sent after the
                        subscription is established.

   After T3, the publisher triggers a 'push-change-update' notification
   announcing an interface status change to the receiver as depicted in
   Figure 8.  In this case, the 'ietf-yp-observation:timestamp' node
   characterizes the moment the interface changed its status at T3 while
   the value of the 'event-time' node characterizes the moment the YANG-
   Push process generated the message at T4.













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   {
     "ietf-yp-notification:envelope": {
       "event-time": "2025-03-25T08:35:12.22Z",
       "hostname": "example-router",
       "sequence-number": 1,
       "contents": {
         "ietf-yang-push:push-change-update": {
           "id": 2222,
           "ietf-yp-observation:timestamp": "2025-03-25T08:34:05.22Z",
           "ietf-yp-observation:point-in-time": "state-changed",
           "datastore-contents": {
             "yang-patch": {
               "patch-id": "52",
               "edit": {
                 "edit-id": "edit_example_1",
                 "operation": "replace",
                 "target": "/ietf-interfaces:interfaces",
                 "value": {
                   "ietf-interfaces:interfaces": {
                     "interface": [{
                       "name": "eth0",
                       "type": "iana-if-type:ethernetCsmacd",
                       "if-index": 1,
                       "admin-status": "up",
                       "oper-status": "down",
                       "statistics": {
                         "discontinuity-time": "2025-03-25T06:43:12Z"
                       }
                     }]
                   }
                 }
               }
             }
           }
         }
       }
     }
   }

     Figure 8: JSON Push Example for a push-change-update notification
                                  message

3.5.1.1.2.  Periodical Subscriptions

   In periodical subscription, the observation time characterizes the
   time when the metrics were polled from the datastore before it
   generates the actual YANG-Push message.




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   Figure 9 illustrates the delays associated with the generation of the
   YANG-Push message.  The timeline shows the following states:

   *  T1: First, the periodical subscription is configured to push the
      operational status of the interface every N interval.

   *  T2: This is the moment the YANG-Push process polls the data state
      data and metrics from the datastore.

   *  T3: After polling the metrics, the YANG-Push process generates the
      'push-update' notification.

       Timeline
       ------------------------------------------------------>
       | (T1) YANG-Push | (T2) YANG-Push | (T3) YANG-Push
       | "periodical"   | process polls  | "periodical"
       | subscription   | the metrics    | current
       | for interface  | from the       | accounting.
       | counter is     | datastore.     |
       | established    |                |
       v                v                v

           Figure 9: Example timeline for Periodical Subscription

   An example of a 'push-update' notification sent at T3 is illustrated
   in Figure 10.  In this case, the node 'event-time' characterizes the
   moment the YANG-Push process generated the message while the node
   'ietf-yp-observation:timestamp' establishes the moment when the
   metrics were polled from the datastore.  For these periodical
   subscriptions, the 'point-in-time' node must be set to 'current-
   accounting'.




















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   {
     "ietf-yp-notification:envelope": {
       "event-time": "2023-03-25T08:30:12.25Z",
       "hostname": "example-router",
       "sequence-number": 1,
       "contents": {
         "ietf-yang-push:push-update": {
           "id": 6666,
           "ietf-yp-observation:timestamp": "2023-03-25T08:30:00.00Z",
           "ietf-yp-observation:point-in-time": "current-accounting",
           "datastore-contents": {
             "ietf-interfaces:interfaces": {
               "interface": [{
                 "name": "eth0",
                 "type": "iana-if-type:ethernetCsmacd",
                 "if-index": 1,
                 "admin-status": "up",
                 "oper-status": "up",
                 "statistics": {
                   "discontinuity-time": "2023-03-25T07:43:12Z",
                   "in-octets": 200,
                   "in-octets": 250
                 }
               }]
             }
           }
         }
       }
     }
   }

    Figure 10: JSON Push Example for a push-update notification message

4.  Operational Considerations

   The header defined by NETCONF Event Notifications [RFC5277] and the
   notification envelope defined in this document may coexist in a
   network.  An operator deploying the header defined in this document
   should take the appropriate actions when both headers are used within
   the same network.  It is RECOMMENDED to deploy one receiver for each
   header.

5.  YANG Modules

5.1.  The 'ietf-yp-notification' Module

   The following sections show the YANG tree and YANG module for the
   'ietf-yp-notification' module.



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5.1.1.  YANG ietf-yp-notification Tree Diagram

   This YANG module extends "ietf-subscribed-notifications" [RFC8641]
   and "ietf-notification-capabilities" [RFC9196] as shown in the
   following YANG tree [RFC8340]:

   module: ietf-yp-notification

     augment /sn:subscriptions:
       +--rw enable-notification-envelope?   boolean
       +--rw metadata
     augment /sysc:system-capabilities/notc:subscription-capabilities:
       +--ro notification-metadata
          +--ro notification-envelope?   boolean
          +--ro metadata
             +--ro hostname-sequence-number?   boolean

     structure envelope:
       +-- event-time         yang:date-and-time
       +-- hostname?          inet:host
       +-- sequence-number?   yang:counter32
       +-- contents?          <anydata>

5.1.2.  YANG ietf-yp-notification Module

   The YANG module augments the module "ietf-subscribed-notifications"
   [RFC8641], augments the module "ietf-notification-capabilities"
   [RFC9196] and uses "ietf-yang-types" module [RFC6991] and "ietf-yang-
   structure-ext" module [RFC8791].

   <CODE BEGINS> file "ietf-yp-notification@2025-06-04.yang"
   module ietf-yp-notification {
     yang-version 1.1;
     namespace "urn:ietf:params:xml:ns:yang:ietf-yp-notification";
     prefix iypn;

     import ietf-yang-types {
       prefix yang;
       reference
         "RFC 6991: Common YANG Data Types";
     }
     import ietf-inet-types {
       prefix inet;
       reference
         "RFC 6991: Common YANG Data Types";
     }
     import ietf-subscribed-notifications {
       prefix sn;



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       reference
         "RFC 8639: Subscription to YANG Notifications";
     }
     import ietf-system-capabilities {
       prefix sysc;
       reference
         "RFC 9196: YANG Modules Describing Capabilities for
          Systems and Datastore Update Notifications";
     }
     import ietf-notification-capabilities {
       prefix notc;
       reference
         "RFC 9196: YANG Modules Describing Capabilities for
          Systems and Datastore Update Notifications";
     }
     import ietf-yang-structure-ext {
       prefix sx;
       reference
         "RFC 8791: YANG Data Structure Extensions";
     }

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

        Authors:  Alex Huang Feng
                  <mailto:alex.huang-feng@insa-lyon.fr>
                  Pierre Francois
                  <mailto:pierre.francois@insa-lyon.fr>
                  Thomas Graf
                  <mailto:thomas.graf@swisscom.com>
                  Benoit Claise
                  <mailto:benoit.claise@huawei.com>";
     description
       "Defines a notification header for Subscribed Notifications
        [RFC8639] and YANG-Push [RFC8641]. When this notification header
        is enabled through configuration, the root container of the
        notification is encoded as defined in RFCXXX.

        This module can be used to validate XML-encoded notifications
        [RFC7950], JSON-encoded messages [RFC7951], and CBOR-encoded
        messages [RFC9254]. Refer to Section Y of RFC XXXX for more
        details.

        Copyright (c) 2025 IETF Trust and the persons identified as
        authors of the code.  All rights reserved.



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        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.";

     revision 2025-06-04 {
       description
         "First revision";
       reference
         "RFC XXXX: YANG-Push Notification Envelope";
     }

     identity notif-envelope-error {
       description
         "Base identity for errors found while attempting to
          change the value of the leaf 'enable-notification-envelope'.";
     }

     grouping notif-env-capabilities {
       description
         "This grouping defines the capabilities for
          the notification-envelope defined in RFC XXXX
          and the different supported metadata.";
       leaf notification-envelope {
         type boolean;
         default "false";
         description
           "Supports YANG-Push to use the notification-envelope
            defined in RFC XXXX.";
       }
       container metadata {
         description
           "Container with the supported optional metadata by the
            YANG-Push publisher.";
         leaf hostname-sequence-number {
           type boolean;
           default "false";
           description
             "Supports hostname and sequence-number
              in the YANG-Push notifications as defined in the
              YANG-Push notification-envelope in RFC XXXX.";
         }



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       }
     }

     sx:structure envelope {
       leaf event-time {
         type yang:date-and-time;
         mandatory true;
         description
           "The date and time the event was generated by the event
            source. This parameter is of type dateTime and compliant
            to [RFC3339].";
       }
       leaf hostname {
         type inet:host;
         description
           "The hostname of the network node according to
            [RFC1213]. This value is usually configured on the node
            by the administrator to identify the node in
            the network uniquely.";
       }
       leaf sequence-number {
         type yang:counter32;
         description
           "Unique sequence number as described in [RFC9187] for each
            published message.";
       }
       anydata contents {
         description
           "This contains the values defined by the 'notification'
            statement unchanged.";
       }
     }

     // Subscription container
     augment "/sn:subscriptions" {
       description
         "This augmentation adds the configuration switches for
          enabling the notification envelope and metadata.";
       leaf enable-notification-envelope {
         type boolean;
         default "false";
         description
           "Enables YANG-Push to use the notification-envelope
            defined in RFC XXXX.";
       }
       container metadata {
         description
           "Container for configuring optional metadata.";



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       }
     }

     // YANG-Push Capabilities extension
     augment "/sysc:system-capabilities"
           + "/notc:subscription-capabilities" {
       description
         "Extension to the subscription-capabilities model to enable
          clients to learn whether the publisher supports the
          notification-envelope";
       container notification-metadata {
         description
           "Adds the notification metadata capabilities to subscription
            capabilities.";
         uses notif-env-capabilities;
       }
     }
   }
   <CODE ENDS>

5.2.  The 'ietf-yp-observation' Module

   The following sections show the YANG tree and YANG module for the
   'ietf-yp-observation' module.

5.2.1.  YANG ietf-yp-observation Tree Diagram

   This YANG module extends "ietf-yang-push" [RFC8641] and "ietf-
   notification-capabilities" [RFC9196] as shown in the following YANG
   tree [RFC8340]:

   module: ietf-yp-observation

     augment /yp:push-update:
       +--ro timestamp?       yang:date-and-time
       +--ro point-in-time?   enumeration
     augment /yp:push-change-update:
       +--ro timestamp?       yang:date-and-time
       +--ro point-in-time?   enumeration
     augment /sysc:system-capabilities/notc:subscription-capabilities:
       +--ro yang-push-observation-supported?   boolean
               {yang-push-observation-timestamp}?

5.2.2.  YANG ietf-yp-observation Module

   The YANG module augments the module "ietf-yang-push" [RFC8641],
   augments the module "ietf-system-capabilities" [RFC9196].




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   <CODE BEGINS> file "ietf-yp-observation@2025-06-04.yang"
   module ietf-yp-observation {
     yang-version 1.1;
     namespace "urn:ietf:params:xml:ns:yang:ietf-yp-observation";
     prefix ypot;

     import ietf-yang-types {
       prefix yang;
       reference
         "RFC 6991: Common YANG Data Types";
     }
     import ietf-yang-push {
       prefix yp;
       reference
         "RFC 8641: Subscription to YANG Notifications for Datastore Updates";
     }
     import ietf-system-capabilities {
       prefix sysc;
       reference
         "RFC 9196: YANG Modules Describing Capabilities for
          Systems and Datastore Update Notifications";
     }
     import ietf-notification-capabilities {
       prefix notc;
       reference
         "RFC 9196: YANG Modules Describing Capabilities for
          Systems and Datastore Update Notifications";
     }

     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 observation
        time in streaming update notifications.

        Copyright (c) 2025 IETF Trust and the persons identified as
        authors of the code.  All rights reserved.




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        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 2025-06-04 {
       description
         "First revision";
       reference
         "RFC XXXX: Extensible YANG Model for Network Telemetry Notifications";
     }

     feature yang-push-observation-timestamp {
       description
         "This feature indicates the YANG-push Notifications support
          the observation timestamps in streaming update notifications.";
     }

     grouping yang-push-observation {
       description
         "This grouping adds the observation timestamp for the observed metrics.";
       leaf timestamp {
         type yang:date-and-time;
         description
           "This is the time when metrics were observed.";
       }
       leaf point-in-time {
         type enumeration {
           enum current-accounting {
             description
               "For periodical subscriptions, the point-in-time
                where the metrics are being polled and observed.";
           }
           enum initial-state {
             description
               "For 'on-change sync on start' subscriptions, the
                initial point in time when the subscription was established
                and the state was observed.";
           }
           enum state-changed {
             description
               "For 'on-change sync on start' subscriptions, the
                point in time when the state change was observed after the
                subscription was established.";



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           }
         }
         description
           "This describes at which point in time the metrics were observed";
       }
     }

     // Event notifications
     augment "/yp:push-update" {
       description
         "This augmentation adds the observation timestamp of the accounted
          metrics in the push-update notification.";
       uses ypot:yang-push-observation;
     }

     augment "/yp:push-change-update" {
       description
         "This augmentation adds the observation timestamp of the event
          in the push-change-update notification.";
       uses ypot:yang-push-observation;
     }

     // Event capabilities
     augment "/sysc:system-capabilities"
           + "/notc:subscription-capabilities" {
       description
         "Add YANG-Push notification capabilities to system-level capability
          container.";
       leaf yang-push-observation-supported {
         if-feature "yang-push-observation-timestamp";
         type boolean;
         description
           "Specifies whether the publisher supports exporting
            observation-timestamp and point-in-time in notifications.";
         reference
           "RFC XXXX: Extensible YANG Model for YANG-Push Notifications";
       }
     }
   }
   <CODE ENDS>

6.  Implementation Status

   Note to the RFC-Editor: Please remove this section before publishing.







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6.1.  Huawei VRP

   Huawei implemented in push-update and push-change-update
   notifications the timestamp and point-in-time extension as described
   in Section 3.5 for a YANG-Push publisher on UDP-based Transport for
   Configured Subscriptions [I-D.ietf-netconf-udp-notif] in their VRP
   platform.

6.2.  6WIND VSR

   6WIND implemented in push-update and push-change-update notifications
   the timestamp and point-in-time extension as described in Section 3.5
   for a YANG-Push publisher on UDP-based Transport for Configured
   Subscriptions [I-D.ietf-netconf-udp-notif] in their VSR platform.

6.3.  Cisco IOS XR

   Cisco implemented in push-update and push-change-update notifications
   the timestamp and point-in-time extension as described in Section 3.5
   for a YANG-Push publisher on UDP-based Transport for Configured
   Subscriptions [I-D.ietf-netconf-udp-notif] in their IOS XR platform.

7.  Security Considerations

   This section uses the template described in Section 3.7 of
   [I-D.ietf-netmod-rfc8407bis].

   The "ietf-yp-notification" and "ietf-yp-observation" YANG modules
   defines data models that are designed to be accessed via YANG-based
   management protocols, such as NETCONF [RFC6241] and RESTCONF
   [RFC8040].  These protocols have to use a secure transport layer
   (e.g., SSH [RFC6242], TLS [RFC8446], and QUIC [RFC9000]) and have to
   use mutual authentication.

   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.

   There are a number of data nodes defined in this YANG module that are
   writable/creatable/deletable (i.e., "config true", which is the
   default).  All writable data nodes are likely to be reasonably
   sensitive or vulnerable in some network environments.  Write
   operations (e.g., edit-config) and delete operations to these data
   nodes without proper protection or authentication can have a negative
   effect on network operations.  The following subtrees and data nodes
   have particular sensitivities/vulnerabilities:




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   *  /sn:subscriptions/iypn:enable-notification-envelope

   The entries in the list above will show whether the mechanism defined
   in this document is enabled.  Access control MUST be set so that only
   someone with proper access permissions has the ability to access and
   modify this resource.

8.  IANA Considerations

   This document describes the URI used for the IETF XML Registry and
   registers a new YANG module name.

8.1.  URI

   IANA is requested to add this document as a reference in the
   following URI's in the IETF XML Registry [RFC3688].

   URI: urn:ietf:params:xml:ns:yang:ietf-yp-notification
   Registrant Contact: The IESG.
   XML: N/A; the requested URI is an XML namespace.
   Reference: RFC-to-be

   URI: urn:ietf:params:xml:ns:yang:ietf-yp-observation
   Registrant Contact: The IESG.
   XML: N/A; the requested URI is an XML namespace.
   Reference: RFC-to-be

8.2.  YANG module name

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

   name: ietf-yp-notification
   namespace: urn:ietf:params:xml:ns:yang:ietf-yp-notification
   prefix: iypn
   reference: RFC-to-be

   name: ietf-yp-observation
   namespace: urn:ietf:params:xml:ns:yang:ietf-yp-observation
   prefix: ypot
   reference: RFC-to-be

8.3.  YANG SID-file

   IANA is requested to register a new ".sid" file in the "IETF YANG SID
   Registry" [RFC9595]:





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   SID range entry point: TBD
   SID range size: 50
   YANG module name: ietf-yp-notification
   reference: RFC-to-be

   A ".sid" file is proposed in Appendix A.

9.  Acknowledgements

   The authors would like to thank Per Anderson, Andy Bierman, Carsten
   Bormann, Mohamed Boucadair, Tom Petch, Jason Sterne, Kent Watsen and
   Rob Wilton for their review and valuable comments.

10.  References

10.1.  Normative References

   [RFC1213]  McCloghrie, K. and M. Rose, "Management Information Base
              for Network Management of TCP/IP-based internets: MIB-II",
              STD 17, RFC 1213, DOI 10.17487/RFC1213, March 1991,
              <https://www.rfc-editor.org/info/rfc1213>.

   [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>.

   [RFC3339]  Klyne, G. and C. Newman, "Date and Time on the Internet:
              Timestamps", RFC 3339, DOI 10.17487/RFC3339, July 2002,
              <https://www.rfc-editor.org/info/rfc3339>.

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

   [RFC5277]  Chisholm, S. and H. Trevino, "NETCONF Event
              Notifications", RFC 5277, DOI 10.17487/RFC5277, July 2008,
              <https://www.rfc-editor.org/info/rfc5277>.

   [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>.



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   [RFC6991]  Schoenwaelder, J., Ed., "Common YANG Data Types",
              RFC 6991, DOI 10.17487/RFC6991, July 2013,
              <https://www.rfc-editor.org/info/rfc6991>.

   [RFC7950]  Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
              RFC 7950, DOI 10.17487/RFC7950, August 2016,
              <https://www.rfc-editor.org/info/rfc7950>.

   [RFC7951]  Lhotka, L., "JSON Encoding of Data Modeled with YANG",
              RFC 7951, DOI 10.17487/RFC7951, August 2016,
              <https://www.rfc-editor.org/info/rfc7951>.

   [RFC8040]  Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
              Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
              <https://www.rfc-editor.org/info/rfc8040>.

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

   [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>.

   [RFC8791]  Bierman, A., Björklund, M., and K. Watsen, "YANG Data
              Structure Extensions", RFC 8791, DOI 10.17487/RFC8791,
              June 2020, <https://www.rfc-editor.org/info/rfc8791>.

   [RFC9187]  Touch, J., "Sequence Number Extension for Windowed
              Protocols", RFC 9187, DOI 10.17487/RFC9187, January 2022,
              <https://www.rfc-editor.org/info/rfc9187>.

   [RFC9196]  Lengyel, B., Clemm, A., and B. Claise, "YANG Modules
              Describing Capabilities for Systems and Datastore Update
              Notifications", RFC 9196, DOI 10.17487/RFC9196, February
              2022, <https://www.rfc-editor.org/info/rfc9196>.

   [RFC9254]  Veillette, M., Ed., Petrov, I., Ed., Pelov, A., Bormann,
              C., and M. Richardson, "Encoding of Data Modeled with YANG
              in the Concise Binary Object Representation (CBOR)",
              RFC 9254, DOI 10.17487/RFC9254, July 2022,
              <https://www.rfc-editor.org/info/rfc9254>.




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   [W3C.REC-xml-20001006]
              Bray, T., Paoli, J., Sperberg-McQueen, M., and E. Maler,
              "Extensible Markup Language (XML) 1.0 (Second Edition)",
              W3C, October 2000,
              <https://www.w3.org/TR/2000/REC-xml-20001006>.

10.2.  Informative References

   [I-D.ietf-netconf-udp-notif]
              Feng, A. H., Francois, P., Zhou, T., Graf, T., and P.
              Lucente, "UDP-based Transport for Configured
              Subscriptions", Work in Progress, Internet-Draft, draft-
              ietf-netconf-udp-notif-21, 14 May 2025,
              <https://datatracker.ietf.org/doc/html/draft-ietf-netconf-
              udp-notif-21>.

   [I-D.ietf-netmod-rfc8407bis]
              Bierman, A., Boucadair, M., and Q. Wu, "Guidelines for
              Authors and Reviewers of Documents Containing YANG Data
              Models", Work in Progress, Internet-Draft, draft-ietf-
              netmod-rfc8407bis-28, 5 June 2025,
              <https://datatracker.ietf.org/doc/html/draft-ietf-netmod-
              rfc8407bis-28>.

   [RFC6242]  Wasserman, M., "Using the NETCONF Protocol over Secure
              Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011,
              <https://www.rfc-editor.org/info/rfc6242>.

   [RFC6470]  Bierman, A., "Network Configuration Protocol (NETCONF)
              Base Notifications", RFC 6470, DOI 10.17487/RFC6470,
              February 2012, <https://www.rfc-editor.org/info/rfc6470>.

   [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>.

   [RFC8341]  Bierman, A. and M. Bjorklund, "Network Configuration
              Access Control Model", STD 91, RFC 8341,
              DOI 10.17487/RFC8341, March 2018,
              <https://www.rfc-editor.org/info/rfc8341>.






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   [RFC8446]  Rescorla, E., "The Transport Layer Security (TLS) Protocol
              Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
              <https://www.rfc-editor.org/info/rfc8446>.

   [RFC9000]  Iyengar, J., Ed. and M. Thomson, Ed., "QUIC: A UDP-Based
              Multiplexed and Secure Transport", RFC 9000,
              DOI 10.17487/RFC9000, May 2021,
              <https://www.rfc-editor.org/info/rfc9000>.

   [RFC9232]  Song, H., Qin, F., Martinez-Julia, P., Ciavaglia, L., and
              A. Wang, "Network Telemetry Framework", RFC 9232,
              DOI 10.17487/RFC9232, May 2022,
              <https://www.rfc-editor.org/info/rfc9232>.

   [RFC9595]  Veillette, M., Ed., Pelov, A., Ed., Petrov, I., Ed.,
              Bormann, C., and M. Richardson, "YANG Schema Item
              iDentifier (YANG SID)", RFC 9595, DOI 10.17487/RFC9595,
              July 2024, <https://www.rfc-editor.org/info/rfc9595>.

Appendix A.  .sid file

   Note to the RFC-Editor: Please remove this section before publishing.

   For CBOR encoding using YANG-SIDs identifiers, a ".sid" file is
   requested to IANA in Section 8.3.

   <CODE BEGINS> file "ietf-yp-notification@2025-06-04.sid"
   {
     "ietf-sid-file:sid-file": {
       "module-name": "ietf-yp-notification",
       "module-revision": "2025-06-04",
       "sid-file-status":"unpublished",
       "description": "draft-ietf-netconf-notif-envelope-02: Extensible YANG Model for YANG-Push Notifications",
       "dependency-revision": [
         {
           "module-name":"ietf-datastores",
           "module-revision":"2018-02-14"
         },
         {
           "module-name":"ietf-interfaces",
           "module-revision":"2018-02-20"
         },
         {
           "module-name":"ietf-ip",
           "module-revision":"2018-02-22"
         },
         {
           "module-name":"ietf-netconf-acm",



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           "module-revision":"2018-02-14"
         },
         {
           "module-name":"ietf-network-instance",
           "module-revision":"2019-01-21"
         },
         {
           "module-name":"ietf-restconf",
           "module-revision":"2017-01-26"
         },
         {
           "module-name":"ietf-yang-library",
           "module-revision":"2019-01-04"
         },
         {
           "module-name":"ietf-yang-patch",
           "module-revision":"2017-02-22"
         },
         {
           "module-name":"ietf-yang-schema-mount",
           "module-revision":"2019-01-14"
         },
         {
           "module-name": "ietf-yang-types",
           "module-revision": "2013-07-15"
         },
         {
           "module-name": "ietf-inet-types",
           "module-revision": "2021-02-22"
         },
         {
           "module-name": "ietf-subscribed-notifications",
           "module-revision": "2019-09-09"
         },
         {
           "module-name": "ietf-system-capabilities",
           "module-revision": "2022-02-17"
         },
         {
           "module-name": "ietf-notification-capabilities",
           "module-revision": "2022-02-17"
         },
         {
           "module-name": "ietf-yang-structure-ext",
           "module-revision": "2020-06-17"
         }
       ],
       "assignment-range": [



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         {
           "entry-point": "2950",
           "size": "50"
         }
       ],
       "item": [
         {
           "status":"unstable",
           "namespace":"module",
           "identifier":"ietf-yp-notification",
           "sid":"2950"
         },
         {
           "status":"unstable",
           "namespace":"identity",
           "identifier":"notif-envelope-error",
           "sid":"2951"
         },
         {
           "status":"unstable",
           "namespace":"data",
           "identifier":"/ietf-subscribed-notifications:subscriptions/ietf-yp-notification:enable-notification-envelope",
           "sid":"2952"
         },
         {
           "status":"unstable",
           "namespace":"data",
           "identifier":"/ietf-subscribed-notifications:subscriptions/ietf-yp-notification:metadata",
           "sid":"2953"
         },
         {
           "status":"unstable",
           "namespace":"data",
           "identifier":"/ietf-system-capabilities:system-capabilities/ietf-notification-capabilities:subscription-capabilities/ietf-yp-notification:notification-metadata",
           "sid":"2954"
         },
         {
           "status":"unstable",
           "namespace":"data",
           "identifier":"/ietf-system-capabilities:system-capabilities/ietf-notification-capabilities:subscription-capabilities/ietf-yp-notification:notification-metadata/notification-envelope",
           "sid":"2955"
         },
         {
           "status":"unstable",
           "namespace":"data",
           "identifier":"/ietf-system-capabilities:system-capabilities/ietf-notification-capabilities:subscription-capabilities/ietf-yp-notification:notification-metadata/metadata",
           "sid":"2956"
         },



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         {
           "status":"unstable",
           "namespace":"data",
           "identifier":"/ietf-system-capabilities:system-capabilities/ietf-notification-capabilities:subscription-capabilities/ietf-yp-notification:notification-metadata/metadata/hostname-sequence-number",
           "sid":"2957"
         },
         {
           "status":"unstable",
           "namespace":"data",
           "identifier":"/ietf-yp-notification:envelope",
           "sid":"2958"
         },
         {
           "status":"unstable",
           "namespace":"data",
           "identifier":"/ietf-yp-notification:envelope/contents",
           "sid":"2959"
         },
         {
           "status":"unstable",
           "namespace":"data",
           "identifier":"/ietf-yp-notification:envelope/event-time",
           "sid":"2960"
         },
         {
           "status":"unstable",
           "namespace":"data",
           "identifier":"/ietf-yp-notification:envelope/hostname",
           "sid":"2961"
         },
         {
           "status":"unstable",
           "namespace":"data",
           "identifier":"/ietf-yp-notification:envelope/sequence-number",
           "sid":"2962"
         }
       ]
     }
   }
   <CODE ENDS>

           Figure 11: .sid file for "ietf-yp-notification" module









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Appendix B.  Example extending the Notification Envelope

   This appendix provides a non-normative example illustrating how an
   extension to the notification envelope should be implemented.  The
   example does not define valid metadata, but serves to demonstrate how
   future extensions should be specified.

   Specifically, the example extends the notification envelope with a
   metadata field named "foo".  The YANG module illustrates the
   necessary augmentations to both the 'ietf-yp-notification' module and
   the 'ietf-notification-capabilities' module.

   <CODE BEGINS> file "example-foo-extension.yang"
   module example-foo-extension {
     yang-version 1.1;
     namespace "urn:ietf:params:xml:ns:yang:example-foo-extension";
     prefix fooext;

     import ietf-subscribed-notifications {
       prefix sn;
     }
     import ietf-system-capabilities {
       prefix sysc;
     }
     import ietf-notification-capabilities {
       prefix notc;
     }
     import ietf-yang-structure-ext {
       prefix sx;
     }
     import ietf-yp-notification {
       prefix iypn;
     }

     description
       "Defines a new 'foo' metadata for the notification envelope.";

     // Extending the notification envelope header with a new
     // 'foo' metadata
     sx:augment-structure "/iypn:envelope" {
       leaf foo {
         type string;
         description
           "Description of the 'foo' extension.";
       }
     }

     // Extending the notifications capabilities so that clients can



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     // learn whether this new extension is supported or not
     augment "/sysc:system-capabilities"
           + "/notc:subscription-capabilities"
           + "/iypn:notification-metadata/iypn:metadata" {
       description
         "Extension to the subscription-capabilities model to enable
          clients to learn whether the publisher supports the new
          'foo' metadata.";
       leaf foo {
         type boolean;
         default "false";
         description
           "Adds the 'foo' capability.";
       }
     }

     // (Optional) A user can optionally add knobs for enabling and
     // disabling specific metadata.
     augment "/sn:subscriptions/iypn:metadata" {
       description
         "An user can optionally, support a configuration knob for enabling
          or disabling a metadata.";
       leaf foo {
         type boolean;
         default "false";
         description
           "Configuration knob for enabling and disabling the 'foo' metadata.";
       }
     }
   }
   <CODE ENDS>

   The extensions result in the following YANG tree:

   module: example-foo-extension

     augment /sysc:system-capabilities/notc:subscription-capabilities
               /iypn:notification-metadata/iypn:metadata:
       +--ro foo?   boolean
     augment /sn:subscriptions/iypn:metadata:
       +--rw foo?   boolean

     augment-structure /iypn:envelope:
       +-- foo?   string

Authors' Addresses





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


   Pierre Francois
   INSA-Lyon
   Lyon
   France
   Email: pierre.francois@insa-lyon.fr


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


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


























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