draft-tgraf-netconf-yang-notifications-versioning-00.txt

Network Working Group                                            T. Graf
Internet-Draft                                                  Swisscom
Intended status: Standards Track                               B. Claise
Expires: 23 April 2023                                            Huawei
                                                           A. Huang Feng
                                                               INSA-Lyon
                                                         20 October 2022


        Support of Versioning in YANG Notifications Subscription
          draft-tgraf-netconf-yang-notifications-versioning-00

Abstract

   This document extends the YANG notifications subscription mechanism
   to specify the YANG module semantic version at the subscription.
   Then, a new extension with new metadata of the YANG push update
   notification header is proposed.

Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on 23 April 2023.

Copyright Notice

   Copyright (c) 2022 IETF Trust and the persons identified as the
   document authors.  All rights reserved.



Graf, et al.              Expires 23 April 2023                 [Page 1]

Internet-Draft        YANG Notifications Versioning         October 2022


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

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Extend the Datastore Selection  . . . . . . . . . . . . . . .   3
   3.  Extend the Metadata in Streaming Update . . . . . . . . . . .   4
   4.  The "ietf-yang-push-metadata" Module  . . . . . . . . . . . .   6
     4.1.  Data Model Overview . . . . . . . . . . . . . . . . . . .   6
     4.2.  YANG Module . . . . . . . . . . . . . . . . . . . . . . .   7
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .  10
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  11
   7.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  11
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  11
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .  11
     8.2.  Informative References  . . . . . . . . . . . . . . . . .  12
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  13

1.  Introduction

   In order to process the received YANG push notification messages
   described in section 3.7 of [RFC8641] at the YANG push receiver, a
   semantic reference to the YANG module and the XPath or subtree is
   needed to determine the data types for each field and which part of
   the YANG module the metrics are expose from.

   This specification applies to the YANG push configured subscriptions
   defined in Section 2.5 of [RFC8639], where a publisher is configured
   to stream notification out of band, as opposed to dynamic
   subscriptions defined in Section 2.4 of [RFC8641], where the
   subscriber can initiate and modify the subscription dynamically in-
   band.  In the latter case, the subscriber knows already all the
   subscriber YANG-related information, which it has to know in order to
   configure the subscription.










Graf, et al.              Expires 23 April 2023                 [Page 2]

Internet-Draft        YANG Notifications Versioning         October 2022


   This semantic reference is available during the subscription period
   described in Section 3.6 of [RFC8641] where for each subscription a
   locally unique subscription ID described in Section 4.3.2 of
   [RFC8641] is being issued and streamed as metadata with the
   notification message in the YANG push message header.  This implies
   that the YANG receiver needs to lookup the subscription inventory for
   a subscription ID in each notification message to determine the YANG
   module name, namespace, and filter definitions.

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

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

   This documents extends the current YANG notifications subscription
   mechanism to allow to subscribe to a specific revision or latest
   semantic version to which the YANG module version needs to be
   backward compatible to and advertises its specific YANG module
   revision inband.  Besides the existing Subscription ID, the YANG
   module name, namespace, revision and filtering metadata is added to
   the YANG push notification header to lift the YANG push receiver need
   to lookup the subscription inventory information.

2.  Extend the Datastore Selection

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

   latest:  Restricts the subscription to the latest YANG module
      revision.

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

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




Graf, et al.              Expires 23 April 2023                 [Page 3]

Internet-Draft        YANG Notifications Versioning         October 2022


   If nothing is specified, latest YANG module version is implied.

3.  Extend the Metadata in Streaming Update

   Along with the subscribed content, besides the Subcription ID, the
   following metadata objects are part of a "push-update" or "push-
   change-update" notification.

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

   namespace:  Describes the YANG module namespace as specified in
      Section 7.1.3 of [RFC6020] for the related streamed content.

   revision:  Describes the YANG module revision as specified in
      Section 7.1.2 of [RFC6020] for the related streamed content.

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

   datastore-xpath-filter:  Describes the YANG module xpath filter as
      specified in Section 6.4 of [RFC6020] for the related streamed
      content.

   datastore-subtree-filter:  Describes the YANG module subtree filter
      as specified in Section 6 of [RFC6241] for the related streamed
      content.

   Figure 1 provides an example of a notification message with the YANG
   module name, revision, revision label and datastore-xpath-filter for
   a subscription tracking the operational status of a single Ethernet
   interface (per [RFC8343]).  This notification message is encoded XML
   [W3C.REC-xml-20081126] over the Network Configuration Protocol
   (NETCONF) as per [RFC8640].
















Graf, et al.              Expires 23 April 2023                 [Page 4]

Internet-Draft        YANG Notifications Versioning         October 2022


<notification xmlns="urn:ietf:params:xml:ns:netconf:notification:1.0">
 <eventTime>2022-09-02T10:59:55.32Z</eventTime>
 <push-update xmlns="urn:ietf:params:xml:ns:yang:ietf-yang-push">
   <id>101</id>
   <module>ietf-interfaces</module>
   <namespace>urn:ietf:params:xml:ns:yang:ietf-interfaces</namespace>
   <revision>2014-05-08</revision>
   <revision-label>1.0.0</revision-label>
   <datastore-xpath-filter>ietf-interfaces:interfaces</datastore-xpath-filter>
   <datastore-contents>
      <interfaces xmlns="urn:ietf:params:xml:ns:yang:ietf-interfaces">
       <interface>
         <name>eth0</name>
         <oper-status>up</oper-status>
       </interface>
     </interfaces>
   </datastore-contents>
 </push-update>
</notification>

 Figure 1: XML Push Example for a Periodical Notification Message


   Figure 2 provides an example of a JSON encoded, [RFC8259],
   notification message over HTTPS-based [I-D.ietf-netconf-https-notif]
   or UDP-based [I-D.ietf-netconf-udp-notif] transport for the same
   subscription.
























Graf, et al.              Expires 23 April 2023                 [Page 5]

Internet-Draft        YANG Notifications Versioning         October 2022


{
    "ietf-notification:notification": {
        "eventTime": "2022-09-02T10:59:55.32Z",
        "ietf-yang-push:push-update": {
            "id": 101,{
            "module": "ietf-interfaces",{
            "namespace": "urn:ietf:params:xml:ns:yang:ietf-interfaces",{
            "revision": "2014-05-08",{
            "revision-label": "1.0.0",{
            "datastore-xpath-filter": "ietf-interfaces:interfaces",
            "datastore-contents": {
                "ietf-interfaces:interface": {
                    "name": {
                        "eth0": {
                                "oper-status": "up",
                                }
                             }
                          }
                       }
                    }
                 }
              }
           }
       }
   }
}

 Figure 2: JSON Push Example for a Periodical Notification Message


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

4.1.  Data Model Overview

   This YANG module augments the "ietf-yang-push" module to add
   subcription metadata into the "push-update" and "push-change-update"
   notification and the ability to define the "revision" and "revision-
   label" in the "establish-subscription" and "modify-subscription" in
   the datastore push subscription.












Graf, et al.              Expires 23 April 2023                 [Page 6]

Internet-Draft        YANG Notifications Versioning         October 2022


   module: ietf-yang-push-metadata

     augment /yp:push-update:
       +--ro module?                     string
       +--ro namespace?                  string
       +--ro revision?                   rev:revision-date-or-label
       +--ro revision-label?             ysver:version
       +--ro datastore-xpath-filter?     yang:xpath1.0 {sn:xpath}?
       +--ro datastore-subtree-filter?   <anydata> {sn:subtree}?
     augment /yp:push-change-update:
       +--ro module?                     string
       +--ro namespace?                  string
       +--ro revision?                   rev:revision-date-or-label
       +--ro revision-label?             ysver:version
       +--ro datastore-xpath-filter?     yang:xpath1.0 {sn:xpath}?
       +--ro datastore-subtree-filter?   <anydata> {sn:subtree}?
     augment /sn:establish-subscription/sn:input/sn:target:
       +-- revision?         rev:revision-date-or-label
       +-- revision-label?   ysver:version
     augment /sn:modify-subscription/sn:input/sn:target:
       +-- revision?         rev:revision-date-or-label
       +-- revision-label?   ysver:version
     augment /sn:subscription-started/sn:target:
       +-- revision?         rev:revision-date-or-label
       +-- revision-label?   ysver:version
     augment /sn:subscription-modified/sn:target:
       +-- revision?         rev:revision-date-or-label
       +-- revision-label?   ysver:version
     augment /sn:subscriptions/sn:subscription/sn:target:
       +--rw revision?         rev:revision-date-or-label
       +--rw revision-label?   ysver:version

4.2.  YANG Module

   The YANG module has six leaves augmenting the model of YANG-push
   [RFC8641].

   <CODE BEGINS> file "ietf-yang-push-metadata@2022-10-10.yang"
   module ietf-yang-push-metadata {
     yang-version 1.1;
     namespace
       "urn:ietf:params:xml:ns:yang:ietf-yang-push-metadata";
     prefix ypm;
     import ietf-yang-types {
       prefix yang;
       reference
         "RFC 6991: Common YANG Data Types";
     }



Graf, et al.              Expires 23 April 2023                 [Page 7]

Internet-Draft        YANG Notifications Versioning         October 2022


     import ietf-subscribed-notifications {
       prefix sn;
       reference
         "RFC 8639: Subscription to YANG Notifications";
     }
     import ietf-yang-push {
       prefix yp;
       reference
         "RFC 8641: Subscription to YANG Notifications for Datastore Updates";
     }
     import ietf-yang-revisions {
       prefix rev;
       reference
         "RFC XXXX: draft-ietf-netmod-yang-module-versioning-06, Updated YANG
         Module Revision Handling";
     }
     import ietf-yang-semver {
       prefix ysver;
       reference
         "RFC XXXX: draft-ietf-netmod-yang-semver-07, YANG Semantic Versioning";
     }

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

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

     description
       "Defines YANG push event notification header with metadata.

       Copyright (c) 2022 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.";



Graf, et al.              Expires 23 April 2023                 [Page 8]

Internet-Draft        YANG Notifications Versioning         October 2022


     revision 2022-09-21 {
       description
         "First revision";
       reference
         "RFC XXXX: Support of Versioning in YANG Notifications Subscription";
     }

     feature yang-push-metadata-supported {
       description
         "This feature indicates the YANG Notifications have the metadata
         defined in this YANG module.";
     }

     grouping yang-push-module-version {
       leaf revision {
         type rev:revision-date-or-label;
         description
           "This references the YANG module revision of the sent notification.";
       }
       leaf revision-label {
         type ysver:version;
         description
           "This references the YANG module semversion of the sent notification.";
       }
     }

     grouping yang-push-metadata {
       leaf module {
         type string;
         description
           "This references the YANG module of the sent notification.";
       }
       leaf namespace {
         type string;
         description
           "This references the YANG module namespace of the sent notification.";
       }

       uses ypm:yang-push-module-version;

       leaf datastore-xpath-filter {
         type yang:xpath1.0;
         if-feature "sn:xpath";
         description
           "This references the YANG module xpath of the sent notification.";
       }
       anydata datastore-subtree-filter {
         if-feature "sn:subtree";



Graf, et al.              Expires 23 April 2023                 [Page 9]

Internet-Draft        YANG Notifications Versioning         October 2022


         description
           "This references the YANG module subtree of the sent notification.";
       }
     }
     // Event notifications
     augment "/yp:push-update" {
       description
         "This augmentation adds the module, the namespace, the revision, the
         semversion, the xpath and the subtree in the push-update notification";
       uses ypm:yang-push-metadata;
     }

     augment "/yp:push-change-update" {
       description
         "This augmentation adds the module, the namespace, the revision, the
         semversion, the xpath and the subtree in the push-change-update notification";
         uses ypm:yang-push-metadata;
     }

     // Subscription parameters
     augment "/sn:establish-subscription/sn:input/sn:target" {
       uses ypm:yang-push-module-version;
     }
     augment "/sn:modify-subscription/sn:input/sn:target" {
       uses ypm:yang-push-module-version;
     }

     // Subscription notifications
     augment "/sn:subscription-started/sn:target" {
       uses ypm:yang-push-module-version;
     }
     augment "/sn:subscription-modified/sn:target" {
       uses ypm:yang-push-module-version;
     }

     // Subscription container
     augment "/sn:subscriptions/sn:subscription/sn:target" {
       uses ypm:yang-push-module-version;
     }
   }
   <CODE ENDS>

5.  Security Considerations

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




Graf, et al.              Expires 23 April 2023                [Page 10]

Internet-Draft        YANG Notifications Versioning         October 2022


6.  IANA Considerations

   This document has no IANA actions.

7.  Acknowledgements

   The authors would like to thank xxx for their review and valuable
   comments.

8.  References

8.1.  Normative References

   [I-D.ietf-netmod-yang-module-versioning]
              Wilton, R., Rahman, R., Lengyel, B., Clarke, J., and J.
              Sterne, "Updated YANG Module Revision Handling", Work in
              Progress, Internet-Draft, draft-ietf-netmod-yang-module-
              versioning-06, 10 July 2022,
              <https://www.ietf.org/archive/id/draft-ietf-netmod-yang-
              module-versioning-06.txt>.

   [I-D.ietf-netmod-yang-semver]
              Clarke, J., Wilton, R., Rahman, R., Lengyel, B., Sterne,
              J., and B. Claise, "YANG Semantic Versioning", Work in
              Progress, Internet-Draft, draft-ietf-netmod-yang-semver-
              07, 10 July 2022, <https://www.ietf.org/archive/id/draft-
              ietf-netmod-yang-semver-07.txt>.

   [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>.

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

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

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





Graf, et al.              Expires 23 April 2023                [Page 11]

Internet-Draft        YANG Notifications Versioning         October 2022


   [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>.

8.2.  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-12, 22 August 2022,
              <https://www.ietf.org/archive/id/draft-ietf-netconf-https-
              notif-12.txt>.

   [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-08, 12 September 2022,
              <https://www.ietf.org/archive/id/draft-ietf-netconf-udp-
              notif-08.txt>.

   [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>.

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

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

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




Graf, et al.              Expires 23 April 2023                [Page 12]

Internet-Draft        YANG Notifications Versioning         October 2022


Authors' Addresses

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


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


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































Graf, et al.              Expires 23 April 2023                [Page 13]