draft-tgraf-netconf-yang-push-observation-time-02.txt

Network Working Group                                            T. Graf
Internet-Draft                                                  Swisscom
Intended status: Standards Track                               B. Claise
Expires: 4 January 2025                                           Huawei
                                                           A. Huang Feng
                                                               INSA-Lyon
                                                             3 July 2024


      Support of Observation Timestamp in YANG-Push Notifications
           draft-tgraf-netconf-yang-push-observation-time-02

Abstract

   This document extends YANG-Push Notifications with the YANG objects
   observation timestamp and point-in-time for streaming update YANG-
   Push notifications.

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 4 January 2025.

Copyright Notice

   Copyright (c) 2024 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents (https://trustee.ietf.org/
   license-info) in effect on the date of publication of this document.
   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.  Code Components
   extracted from this document must include Revised BSD License text as
   described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Revised BSD License.



Graf, et al.             Expires 4 January 2025                 [Page 1]

Internet-Draft     YANG Notifications Observation Time         July 2024


Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminologies . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Extend the Streaming Update Notifications . . . . . . . . . .   3
   4.  YANG-Push capabilities  . . . . . . . . . . . . . . . . . . .   7
   5.  The "ietf-yp-observation" YANG Module . . . . . . . . . . . .   7
     5.1.  Data Model Overview . . . . . . . . . . . . . . . . . . .   7
     5.2.  YANG Module . . . . . . . . . . . . . . . . . . . . . . .  10
   6.  Implementation Status . . . . . . . . . . . . . . . . . . . .  13
     6.1.  6WIND VSR . . . . . . . . . . . . . . . . . . . . . . . .  13
   7.  Operational Considerations  . . . . . . . . . . . . . . . . .  13
     7.1.  Time Series Late Indexing . . . . . . . . . . . . . . . .  13
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .  13
   9.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  13
     9.1.  URI . . . . . . . . . . . . . . . . . . . . . . . . . . .  13
     9.2.  YANG module name  . . . . . . . . . . . . . . . . . . . .  14
   10. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  14
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .  14
     11.1.  Normative References . . . . . . . . . . . . . . . . . .  14
     11.2.  Informative References . . . . . . . . . . . . . . . . .  15
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  15

1.  Introduction

   To correlate network data among different Network Telemetry planes as
   described in Section 3.1 of [RFC9232] or among different YANG-Push
   subscription types defined in Section 3.1 of [RFC8641], observation
   timestamp describes when the state change was observed or when the
   data was accounted.  This is essential for understanding the timely
   relationship among these different planes and YANG push subscription
   types.

   With [I-D.tgraf-netconf-notif-sequencing] the delay between the YANG
   Notification export and the arrival at the downstream system storing
   the data can be measured.  With observation timestamp described in
   this document, the delay between the time of the network observation
   and the data export of the YANG push publisher process can be
   measured as well, extending the delay measurement scope from the time
   the network observation and storing the data.

   When the time bucket length in a time series database and the
   periodical YANG push subscription time is identical, the eventTime of
   the netconf notification message header is used for indexing, there
   is variable delay between the observation timestamp and the
   eventTime, and the anchor-time as described in Section 4.2 of
   [RFC8641] is close to the time bucket boundaries, a time bucket is
   going to have periodically 0 or 2 measurements indexed instead of 1.



Graf, et al.             Expires 4 January 2025                 [Page 2]

Internet-Draft     YANG Notifications Observation Time         July 2024


   Leading to inconsistent accounting errors in the time series
   database.  This problem is resolved by using the observation
   timestamp instead of the eventTime for time series database indexing.

   By extending YANG-Push Notifications with the observation timestamp
   YANG object and a point-in-time enumeration for streaming update
   YANG-Push notifications it is ensured that the observation timestamp
   is always present with the best available time, it can be therefore
   used unconditionally in the data processing chain and with the point-
   in-time enumeration there is semantic describing at which point in
   time the observation timestamp was observed.

2.  Terminologies

   The following terms are defined in [RFC8639] and are not redefined
   here:

   Publisher

   Receiver

   Subscription

   In addition, this document defines the following terms:

   Timestamp: Describes when the metric(s) (reported in YANG-Push
   subscriptions) were observed for a given Subscription ID and
   notification message.

   Point-in-time: Describes at which point in time the metric(s)
   reported in YANG-Push subscriptions) were observed for a given
   Subscription ID and notification message.

3.  Extend the Streaming Update Notifications

   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 a "periodical" and for the "push-change-
      update" notification in a "on-change" subscription.









Graf, et al.             Expires 4 January 2025                 [Page 3]

Internet-Draft     YANG Notifications Observation Time         July 2024


      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 for "periodical" subscriptions, the
      point-in-time where the metrics are being polled and observed.

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

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

   Figure 1 provides an example timeline of events to describe
   observation timestamp and point-in-time for "on-change sync on start"
   subscriptions.  At "T2" when the "on-change sync on start"
   subscription is established, the timestamp of "T2" is used in
   observation timestamp and "point-in-time" is set to "initial-state".
   At "T3" and "T4" the timestamp of "T3" respectively "T4" is used in
   observation timestamp and point-in-time is set to "state-changed".

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

  Figure 1: Example timeline for On-Change Sync on Start Subscription











Graf, et al.             Expires 4 January 2025                 [Page 4]

Internet-Draft     YANG Notifications Observation Time         July 2024


   ========== NOTE: '\' line wrapping per RFC 8792) ===========

   {
     "ietf-notification:notification": {
       "eventTime": "2023-03-25T08:30:11.22Z",
       "ietf-notification-sequencing:sysName": "example-router",
       "ietf-notification-sequencing:sequenceNumber": 1,
       "ietf-yang-push:push-change-update": {
         "id": 2222,
         "ietf-yp-observation:timestamp": \
         "2023-03-25T08:30:11.22Z",
         "ietf-yp-observation:point-in-time": \
         "state-changed",
         "datastore-contents": {
           "yang-patch": {
             "patch-id": "patch_54",
             "comment": "Changing encoding to JSON and increasing \
             the period to 10 minutes",
             "edit": [
               {
                 "edit-id": "id_change_1",
                 "operation": "merge",
                 "target": "/ietf-subscribed-notifications\:subs\
                 criptions/subscription[id=2222]",
                 "value": {
                   "ietf-subscribed-notifications:encoding": \
                   "ietf-subscribed-notifications:encode-json",
                   "ietf-yang-push:periodic": {
                     "period": 60000
                   }
                 }
               }
             ]
           }
         }
       }
     }
   }

     Figure 2: JSON Push Example for a push-change-update notification
                                  message

   Figure 3 provides an example timeline of events to describe point-in-
   time for "periodical" subscriptions.  The timestamp of observation
   timestamp in "T2" is set at the start of the polling of the YANG data
   store to "T2" and point-in-time is set "current-accounting".  At "T3"
   the timestamp of observation timestamp of "T3" is used.  At "T4" the
   timestamp of observation timestamp of "T4" is used.



Graf, et al.             Expires 4 January 2025                 [Page 5]

Internet-Draft     YANG Notifications Observation Time         July 2024


 Timeline
 ---------------------------------------------------------------------->
  | (T1) YANG-Push | (T2) YANG-Push | (T3) YANG-Push | (T4) YANG-Push
  | "periodical"   | "periodical"   | "periodical"   | "periodical"
  | subscription   | current        | current        | current
  | for interface  | accounting     | accounting.    | accounting.
  | counter is     |                |                |
  | established    |                |                |
  v                v                v                v

         Figure 3: Example timeline for Periodical Subscription

   Figure 4 provides an example of a JSON encoded, [RFC8259], "push-
   change-update" notification message over HTTPS-based
   [I-D.ietf-netconf-https-notif] or UDP-based
   [I-D.ietf-netconf-udp-notif] transport with
   [I-D.tgraf-netconf-notif-sequencing] as extension.

   ========== NOTE: '\' line wrapping per RFC 8792) ===========

   {
     "ietf-notification:notification": {
       "eventTime": "2023-03-25T08:30:11.22Z",
       "ietf-notification-sequencing:sysName": "example-router",
       "ietf-notification-sequencing:sequenceNumber": 1,
       "ietf-yang-push:push-update": {
         "id": 6666,
         "ietf-yp-observation:timestamp": \
         "2023-03-25T08:30:11.22Z",
         "ietf-yp-observation:point-in-time": \
         "current-accounting",
         "datastore-contents": {
           "ietf-interfaces:interfaces": [
             {
               "interface": {
                 "name": "eth0",
                 "type": "iana-if-type:ethernetCsmacd",
                 "oper-status": "up",
                 "mtu": 1500
               }
             }
           ]
         }
       }
     }
   }

     Figure 4: JSON Push Example for a push-update notification message



Graf, et al.             Expires 4 January 2025                 [Page 6]

Internet-Draft     YANG Notifications Observation Time         July 2024


4.  YANG-Push capabilities

   YANG-related system capabilities can be discovered by subscribing to
   the datastore defined in [RFC9196].  This document augments the
   "ietf-notification-capabilities" defined in Section 5 of [RFC9196] so
   that the YANG-Push receiver can learn the capabilities defined in
   this documents through the datastore.

   The definition of this YANG augmentation is specified in Section 5.

5.  The "ietf-yp-observation" YANG Module

   This YANG module augments the "ietf-yang-push" module with the
   observation timestamp and point-in-time in the "push-update" and
   "push-change-update" streaming update notifications.

5.1.  Data Model Overview

5.1.1.  Tree View

   This "ietf-yp-observation" YANG module augments the "ietf-yang-push"
   YANG module specified in Section 5 of [RFC8641] adding the
   "timestamp" and the "point-in-time" leaves and augments "ietf-
   notification-capabilities" defined in [RFC9196] to add a system level
   capability.

   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?
               inotifseq:notification-support
               {yang-push-observation-timestamp}?

5.1.2.  Full Tree View

   The following YANG tree diagram [RFC8340] shows the complete
   notification defined in the "ietf-yang-push" module:








Graf, et al.             Expires 4 January 2025                 [Page 7]

Internet-Draft     YANG Notifications Observation Time         July 2024


   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
       |  +--ro ypot:timestamp?          yang:date-and-time
       |  +--ro ypot:point-in-time?      enumeration
       +---n push-change-update {on-change}?
          +--ro id?                      sn:subscription-id
          +--ro datastore-changes
          +--ro incomplete-update?       empty
          +--ro ypot:timestamp?          yang:date-and-time
          +--ro ypot:point-in-time?      enumeration

   The following YANG tree diagram [RFC8340] shows the complete "ietf-
   system-capabilities" module with the augmentations defined in "ietf-
   yp-observation" module:



























Graf, et al.             Expires 4 January 2025                 [Page 8]

Internet-Draft     YANG Notifications Observation Time         July 2024


   module: ietf-system-capabilities
     +--ro system-capabilities
        +--ro datastore-capabilities* [datastore]
        |  +--ro datastore
        |  |       -> /yanglib:yang-library/datastore/name
        |  +--ro per-node-capabilities* []
        |     +--ro (node-selection)?
        |     |  +--:(node-selector)
        |     |     +--ro node-selector?
        |     |             nacm:node-instance-identifier
        |     +--ro notc:subscription-capabilities
        |        +--ro notc:max-nodes-per-update?               uint32
        |        +--ro notc:periodic-notifications-supported?
        |        |       notification-support
        |        +--ro (notc:update-period)?
        |        |  +--:(notc:minimum-update-period)
        |        |  |  +--ro notc:minimum-update-period?        uint32
        |        |  +--:(notc:supported-update-period)
        |        |     +--ro notc:supported-update-period*      uint32
        |        +--ro notc:on-change-supported?
        |        |       notification-support {yp:on-change}?
        |        +--ro notc:minimum-dampening-period?           uint32
        |        |       {yp:on-change}?
        |        +--ro notc:supported-excluded-change-type*     union
        |                {yp:on-change}?
        +--ro notc:subscription-capabilities
           +--ro notc:max-nodes-per-update?               uint32
           +--ro notc:periodic-notifications-supported?
           |       notification-support
           +--ro (notc:update-period)?
           |  +--:(notc:minimum-update-period)
           |  |  +--ro notc:minimum-update-period?        uint32
           |  +--:(notc:supported-update-period)
           |     +--ro notc:supported-update-period*      uint32
           +--ro notc:on-change-supported?
           |       notification-support {yp:on-change}?
           +--ro notc:minimum-dampening-period?           uint32
           |       {yp:on-change}?
           +--ro notc:supported-excluded-change-type*     union
           |       {yp:on-change}?
           +--ro inotifseq:sysname-sequence-supported?
           |       notification-support {sysname-sequence}?
           +--ro ypot:yang-push-observation-supported?
                   inotifseq:notification-support
                   {yang-push-observation-timestamp}?






Graf, et al.             Expires 4 January 2025                 [Page 9]

Internet-Draft     YANG Notifications Observation Time         July 2024


5.2.  YANG Module

   The YANG module has one leave augmenting the model of Subscription to
   YANG Notifications [RFC8639].

   <CODE BEGINS> file "ietf-yp-observation@2024-06-18.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";
     }
     import ietf-notification-sequencing {
       prefix inotifseq;
       reference
         "draft-tgraf-netconf-notif-sequencing-05: YANG Notifications
         Sequencing";
     }
     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>



Graf, et al.             Expires 4 January 2025                [Page 10]

Internet-Draft     YANG Notifications Observation Time         July 2024


                  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) 2024 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 2024-06-18 {
       description
         "First revision";
       reference
         "RFC XXXX: Support of YANG-Push Notifications Observation Time";
     }

     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



Graf, et al.             Expires 4 January 2025                [Page 11]

Internet-Draft     YANG Notifications Observation Time         July 2024


               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.";
           }
         }
         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 system level capabilities";
       leaf yang-push-observation-supported {
         if-feature "yang-push-observation-timestamp";
         type inotifseq:notification-support;
         description
           "Specifies whether the publisher supports exporting
           observation-timestamp and point-in-time in notifications.";
         reference
           "RFC XXXX: YANG Notifications Observation Time";
       }
     }
   }
   <CODE ENDS>






Graf, et al.             Expires 4 January 2025                [Page 12]

Internet-Draft     YANG Notifications Observation Time         July 2024


6.  Implementation Status

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

6.1.  6WIND VSR

   6WIND implemented this document for a YANG Push publisher on
   UDP-based Transport for Configured Subscriptions
   [I-D.ietf-netconf-udp-notif] in their VSR platform.

7.  Operational Considerations

7.1.  Time Series Late Indexing

   Since the timespan between network state change and subscription
   establishment as exampled in timeline with "T1" and "T2" in Figure 1
   for "on-change sync on start" subscriptions could be very long when
   the network node uptime and thus the state change was long time ago
   and the subscription is establish very recent, a time series database
   may discard the notification message at ingestion since the
   observation timestamp is in the very past and therefore would have
   potential performance impact on the time series database indexing.
   This can be circumvent by using the eventTime for indexing or a
   change to "on-change" subscriptions instead.

8.  Security Considerations

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

9.  IANA Considerations

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

9.1.  URI

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

   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:  RFC5277; RFC-to-be



Graf, et al.             Expires 4 January 2025                [Page 13]

Internet-Draft     YANG Notifications Observation Time         July 2024


9.2.  YANG module name

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

   name:  ietf-yp-observation

   namespace:  urn:ietf:params:xml:ns:yang:ietf-yp-observation

   prefix:  ypot

   Reference:  RFC-to-be

10.  Acknowledgements

   The authors would like to thank Rob Wilton, Nick Corran, Pierre
   Francois Ahmed Elhassany, Jean Quilbeuf and Marco Tollini for their
   review and valuable comments.

11.  References

11.1.  Normative References

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

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

   [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>.

   [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>.







Graf, et al.             Expires 4 January 2025                [Page 14]

Internet-Draft     YANG Notifications Observation Time         July 2024


   [RFC8792]  Watsen, K., Auerswald, E., Farrel, A., and Q. Wu,
              "Handling Long Lines in Content of Internet-Drafts and
              RFCs", RFC 8792, DOI 10.17487/RFC8792, June 2020,
              <https://www.rfc-editor.org/info/rfc8792>.

   [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>.

11.2.  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-15, 1 February 2024,
              <https://datatracker.ietf.org/doc/html/draft-ietf-netconf-
              https-notif-15>.

   [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-13, 27 June 2024,
              <https://datatracker.ietf.org/doc/html/draft-ietf-netconf-
              udp-notif-13>.

   [I-D.tgraf-netconf-notif-sequencing]
              Graf, T., Quilbeuf, J., and A. H. Feng, "Support of
              Hostname and Sequencing in YANG Notifications", Work in
              Progress, Internet-Draft, draft-tgraf-netconf-notif-
              sequencing-06, 29 June 2024,
              <https://datatracker.ietf.org/doc/html/draft-tgraf-
              netconf-notif-sequencing-06>.

   [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>.

   [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>.

Authors' Addresses





Graf, et al.             Expires 4 January 2025                [Page 15]

Internet-Draft     YANG Notifications Observation Time         July 2024


   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

































Graf, et al.             Expires 4 January 2025                [Page 16]