NETCONF Working Group                                              Q. Wu
Internet-Draft                                                     Q. Ma
Intended status: Standards Track                                  Huawei
Expires: 28 August 2022                                           P. Liu
                                                            China Mobile
                                                                 W. Wang
                                                           China Telecom
                                                        24 February 2022


                  Data Export Notification Capability
             draft-tao-netconf-data-export-capabilities-07

Abstract

   This document proposes a YANG module for data export notification
   capabilities which augments "ietf-system-capabilities" YANG module
   defined in [RFC9196] and provides additional data export attributes
   associated with system capabilities for transport specific
   Notification.  This YANG module can be used by the client to learn
   capability information from the server at runtime or at
   implementation time, by making use of the YANG instance data file
   format.

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 28 August 2022.

Copyright Notice

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






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

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Data Export Capability  . . . . . . . . . . . . . . . . . . .   3
     2.1.  Tree Diagram  . . . . . . . . . . . . . . . . . . . . . .   4
   3.  YANG Module . . . . . . . . . . . . . . . . . . . . . . . . .   4
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   8
     4.1.  Updates to the IETF XML Registry  . . . . . . . . . . . .   8
     4.2.  Updates to the YANG Module Names Registry . . . . . . . .   8
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   8
   6.  Contributors  . . . . . . . . . . . . . . . . . . . . . . . .   9
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   9
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .   9
     7.2.  Informative References  . . . . . . . . . . . . . . . . .  10
   Appendix A.  Usage Example of interaction with UDP Notif and HTTP
           Notif for Configured Subscription . . . . . . . . . . . .  11
   Appendix B.  Changes between Revisions  . . . . . . . . . . . . .  13
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  14

1.  Introduction

   Notification capabilities model defined in [RFC9196] allows a client
   to discover a set of capabilities supported by the server (e.g.,
   basic system capabilities and YANG-Push related capabilities) both at
   implementation time and at runtime.  These capabilities allow the
   client to adjust its behavior to take advantage of the features
   exposed by the server.

   However the client and the server may still support various different
   transport specific parameters (e.g., transport protocol, encoding
   format, encryption).  As described in section 3.1 of [RFC8641], a
   simple negotiation (i.e., inserting hints into error responses to a
   failed RPC request) between subscribers and publishers for
   subscription parameters increases the likelihood of success for
   subsequent RPC requests, but not guaranteed, which may cause
   unexpected failure or additional message exchange between client and
   server.




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   This document defines a corresponding solution that is built on top
   of [RFC9196].  Supplementing that work are YANG data model
   augmentations for transport specific notification.  The module can be
   used by the client to discover capability information from the server
   at runtime or at implementation time, by making use of the YANG
   instance data file format.

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.

2.  Data Export Capability

   The YANG module "ietf-notification-capabilities" defined in [RFC9196]
   specifies the following server capabilities related to YANG Push:

   *  Supported (reporting) periods for "periodic" subscriptions

   *  Maximum number of objects that can be sent in an update

   *  The set of datastores or data nodes for which "periodic" or "on-
      change" notification is supported

   *  Supported dampening periods for "on-change" subscriptions

   These server capabilities are transport independent, session level
   capabilities.  They can be provided either at the implementation time
   or reported at runtime.

   This document augments System Capabilities model and provides
   additional data export attributes associated with system
   capabilities:

   *  Specification of transport protocols the client can use to
      establish a transport connection;

   *  Specification of the encoding selection used (e.g., XML or JSON,
      Binary) for Data modeled with YANG;

   *  Specification of secure transport mechanisms that are needed by
      the client to communicate with the server;






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   *  Specification of the notification message encapsulation type,
      either one notification per message or multiple notifications per
      message [I-D. ietf-netconf-notification-messages].

2.1.  Tree Diagram

   The following tree diagram [RFC8340] provides an overview of the data
   model.

   module: ietf-data-export-capabilities
     augment /sysc:system-capabilities:
       +--ro data-export-capabilities
          +--ro data-export-capability* []
             +--ro transport-protocol?            identityref
             +--ro encoding-format*               identityref
             +--ro security-protocol?             identityref
             +--ro message-bundling-support?      empty

3.  YANG Module

   <CODE BEGINS> file "ietf-data-export-capabilities.yang"
   module ietf-data-export-capabilities {
     yang-version 1.1;
     namespace "urn:ietf:params:xml:ns:yang:ietf-data-export-capabilities";
     prefix dec;

     import ietf-system-capabilities {
       prefix sysc;
     }
     import ietf-notification-capabilities {
       prefix inc;
     }
     organization
       "IETF NETCONF (Network Configuration) Working Group";
     contact
       "WG Web:   <https://tools.ietf.org/wg/netconf/>
        WG List:  <mailto:netconf@ietf.org>
        Editor:   Qin Wu <mailto:bill.wu@huawei.com>
        Editor:   Qiufang Ma <mailto: maqiufang1@huawei.com>
        Editor:   Peng Liu <mailto: liupengyjy@chinamobile.com>
        Editor:   Wei Wang <mailto: wangw36@chinatelecom.cn>";
     description
       "This module defines an extension to System Capability and YANG Push
        Notification Capabilities model and provides additional data export
        attributes for transport specific notification.

        Copyright (c) 2019 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 Simplified BSD License
        set forth in Section 4.c of the IETF Trust's Legal Provisions
        Relating to IETF Documents
        (http://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 2020-07-03 {
       description
         "Initial revision.";
       reference
         "RFC XXXX: Data Export Notification Capability";
     }

     identity transport-protocol {
       description
         "Base identity for transport protocol type.";
     }

     identity tcp {
       base transport-protocol;
       description
         "Identity for tcp as transport protocol.";
     }

     identity udp-notif {
       base transport-protocol;
       description
         "Identity for udp notif as transport protocol.";
       reference
         "draft-ietf-netconf-udp-notif:UDP-based Transport
          for Configured Subscriptions";
     }

     identity http-notif {
       base transport-protocol;
       description
         "Identity for http notif as transport protocol.";
       reference
         "draft-ietf-netconf-https-notif: An HTTPS-based
          Transport for Configured Subscriptions";
     }

     identity grpc {
       base transport-protocol;



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       description
         "Identity for grpc as transport protocol.";
     }

     identity security-protocol {
       description
         "Base identity for security protocol type.";
     }

     identity tls {
       base security-protocol;
       description
         "Identity for tls security protocol.";
     }

     identity dtls {
       base security-protocol;
       description
         "Identity for dtls security protocol.";
     }

     identity ssh {
       base security-protocol;
       description
         "Identity for ssh transport protocol.";
     }

     identity encoding-format {
       description
         "Base identity for encoding format type.";
     }

     identity xml {
       base encoding-format;
       description
         "Identity for xml encoding format.";
     }

     identity json {
       base encoding-format;
       description
         "Identity for json encoding format.";
     }

     identity binary {
       base encoding-format;
       description
         "Identity for binary encoding format.";



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     }

     identity cbor {
       base binary;
       description
         "Identity for cbor encoding format.";
     }

     augment "/sysc:system-capabilities" {
       description
         "Add system level capability.";
       container data-export-capabilities {
         description
           "Capabilities related to data export notification capabilities negotiation.";
         list data-export-capability {
           description
             "Capability list related to data export notification capabilities negotiation.";
           leaf transport-protocol {
             type identityref {
               base transport-protocol;
             }
             description
               "Type of transport protocol.";
           }
           leaf-list encoding-format {
             type identityref {
               base encoding-format;
             }
             description
               "Type of encoding format.";
           }
           leaf security-protocol {
             type identityref {
               base security-protocol;
             }
             description
               "Type of secure transport.";
           }
           leaf message-bundling-support {
             type empty;
             description
               "Enables message bundling support.";
           }
         }
       }
     }
   }
   <CODE ENDS>



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4.  IANA Considerations

4.1.  Updates to the IETF XML Registry

   This document registers a URI in the "IETF XML Registry" [RFC3688].
   Following the format in [RFC3688], the following registration has
   been made:

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

4.2.  Updates to the YANG Module Names Registry

   This document registers one YANG module in the "YANG Module Names"
   registry [RFC6020].  Following the format in [RFC6020], the following
   registration has been made:

     name:
        ietf-data-export-capabilities
     namespace:
        urn:ietf:params:xml:ns:yang:ietf-data-export-capabilities
     prefix:
        dec
     reference:
        RFC XXXX (RFC Ed.: replace XXX with actual RFC number and remove
        this note.)

5.  Security Considerations

   The YANG module specified in this document defines a schema for data
   that is designed to be accessed via network management protocols such
   as NETCONF [RFC6241] or RESTCONF [RFC8040].  The lowest NETCONF layer
   is the secure transport layer, and the mandatory-to-implement secure
   transport is Secure Shell (SSH) [RFC6242].  The lowest RESTCONF layer
   is HTTPS, and the mandatory-to-implement secure transport is TLS
   [RFC8446].

   The NETCONF 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.






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   All protocol-accessible data nodes are read-only and cannot be
   modified.  The data in these modules is not security sensitive.
   Access control may be configured, to avoid exposing the read-only
   data.

   When this data is in file format, data should be protected against
   modification or unauthorized access using normal file handling
   mechanisms.

6.  Contributors

      Ran Tao
      Huawei
      101 Software Avenue, Yuhua District
      Nanjing, Jiangsu  210012
      China
      Email: taoran20@huawei.com

      Liang Geng
      China Mobile
      32 Xuanwumen West St, Xicheng District
      Beijing  10053

      Email: gengliang@chinamobile.com

      Thomas Graf
      Swisscom
      Binzring 17
      Zuerich 8045
      Switzerland

      Email: thomas.graf@swisscom.com

7.  References

7.1.  Normative References

   [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>.

   [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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   [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>.

   [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>.

   [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>.

   [RFC8126]  Cotton, M., Leiba, B., and T. Narten, "Guidelines for
              Writing an IANA Considerations Section in RFCs", BCP 26,
              RFC 8126, DOI 10.17487/RFC8126, June 2017,
              <https://www.rfc-editor.org/info/rfc8126>.

   [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>.

   [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>.

   [RFC8342]  Bjorklund, M., Schoenwaelder, J., Shafer, P., Watsen, K.,
              and R. Wilton, "Network Management Datastore Architecture
              (NMDA)", RFC 8342, DOI 10.17487/RFC8342, March 2018,
              <https://www.rfc-editor.org/info/rfc8342>.

   [RFC8407]  Bierman, A., "Guidelines for Authors and Reviewers of
              Documents Containing YANG Data Models", BCP 216, RFC 8407,
              DOI 10.17487/RFC8407, October 2018,
              <https://www.rfc-editor.org/info/rfc8407>.

   [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>.

   [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>.

7.2.  Informative References





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   [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-09, 24 October 2021,
              <https://www.ietf.org/archive/id/draft-ietf-netconf-https-
              notif-09.txt>.

   [I-D.ietf-netconf-notification-messages]
              Voit, E., Jenkins, T., Birkholz, H., Bierman, A., and A.
              Clemm, "Notification Message Headers and Bundles", Work in
              Progress, Internet-Draft, draft-ietf-netconf-notification-
              messages-08, 17 November 2019,
              <https://www.ietf.org/archive/id/draft-ietf-netconf-
              notification-messages-08.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-04, 21 October 2021,
              <https://www.ietf.org/archive/id/draft-ietf-netconf-udp-
              notif-04.txt>.

   [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>.

Appendix A.  Usage Example of interaction with UDP Notif and HTTP Notif
             for Configured Subscription

   The following instance-data example describes the Data Export
   Notification capabilities of a hypothetical "acme-router".










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<?xml version="1.0" encoding="UTF-8"?>
<instance-data-set xmlns=
"urn:ietf:params:xml:ns:yang:ietf-yang-instance-data">
  <name>acme-router-notification-capabilities</name>
  <content-schema>
    <module>ietf-system-capabilities@2020-03-23</module>
    <module>ietf-notification-capabilities@2020-03-23</module>
    <module>ietf-data-export-capabilities@2020-03-23</module>
  </content-schema>
  <!-- revision date, contact, etc. -->
  <description>Server Capability Discovery</description>
  <content-data>
    <system-capabilities
      xmlns="urn:ietf:params:xml:ns:yang:ietf-system-capabilities"
      xmlns:inc="urn:ietf:params:xml:ns:yang:ietf-notification-capabilities"
      xmlns:ds="urn:ietf:params:xml:ns:yang:ietf-datastores">
      <data-export-capabilities>
        <data-export-capability>
          <transport-protocol>http-notif</transport-protocol>
          <encoding-format>json</encoding-format>
          <encoding-format>xml</encoding-format>
        </data-export-capability>
        <data-export-capability>
          <transport-protocol>udp-notif</transport-protocol>
          <encoding-format>binary</encoding-format>
        </data-export-capability>
      </data-export-capabilities>
    </system-capabilities>
  </content-data>
</instance-data-set>

   In addition, the client could also query data export capability from
   the server.  For example, the client sends <get> request message to
   the the server to query data export capability from the server.

 <rpc message-id="101" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
   <get>
     <filter type="subtree">
     <system-capabilities xmlns="urn:ietf:params:xml:ns:yang:ietf-system-capabilities">
       <data-export-capabilities/>
     </system-capabilities>
    </filter>
   </get>
 </rpc>

   The server returns server data export capability using <rpc-reply> as
   follows:




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<rpc-reply message-id="101" xmlns="urn:ietf:params:xml:ns:netconf:base:1.0">
  <data>
  <system-capabilities
   xmlns="urn:ietf:params:xml:ns:yang:ietf-system-capabilities"
   xmlns:dec="urn:ietf:params:xml:ns:yang:ietf-data-export-capabilities">
    <data-export-capabilities>
      <data-export-capability>
        <transport-protocol>http-notif</transport-protocol>
        <encoding-format>json</encoding-format>
      </data-export-capability>
      <data-export-capability>
        <transport-protocol>udp-notif</transport-protocol>
        <encoding-format>binary</encoding-format>
      </data-export-capability>
    </data-export-capabilities>
  </system-capabilities>
</data>
</rpc-reply>

Appendix B.  Changes between Revisions

   v06-v07

   *  Delete the per-node related capability parameters from the
      Appendix.

   v05-v06

   *  Revise abstract and introduction sessions so that the scope of
      this draft is not limited to telemetry but other notification.

   *  Revise the description of module ietf-system-capabilities to align
      with the latest version of draft-ietf-netconf-notification-
      capabilities.

   *  Remove compression-mode, timer-event-support and suppress-
      redundant parameters in the model.

   *  Move per-node related capability parameters to appendix section.

   *  Add a container to wrap data export capabilities to cleanly
      separate different groups of capabilities.

   v04 - v05

   *  Change per-node-capabilities related parameters into empty type.





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   *  Revise abstract and introduction section to only focus on
      capability fetching mechanism from the client to the server.

   *  Update Usage Example of interaction with HTTP-Notif and UDP-Notif
      for Configured Subscription.

   v03 - v04

   *  Add interface namespace in the Adaptive Subscription usage
      example.

   *  subtrees and data nodes changes in the security section.

   *  Two compression mode related identities change.

   *  Move message-bundling-support parameer to system capabilities
      level.

   *  Add an example to discuss report reciever capability from the
      client per yang instance file format.

   *  Change encoding format from leaf to leaf-list and support multiple
      encoding formats for the same transport specific notif.

   v02 - v03

   *  Change 'data-export-capabilities' into list type to support
      multiple transport protocol, encoding on the server.

   *  Add Usage Example of interaction with UDP based Transport for
      Configured Subscription.

   *  Add Thomas Graf as a contributor;

   *  Update motivation in the introduction to clarify why this work is
      needed.

   *  Support udp notif and http notif as two optional transport in the
      YANG data model.

Authors' Addresses

   Qin Wu
   Huawei
   101 Software Avenue, Yuhua District
   Nanjing
   Jiangsu, 210012
   China



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   Email: bill.wu@huawei.com


   Qiufang Ma
   Huawei
   101 Software Avenue, Yuhua District
   Nanjing
   Jiangsu, 210012
   China
   Email: maqiufang1@huawei.com


   Peng Liu
   China Mobile
   Beiqijia Town, Changping District
   Beijing
   Email: liupengyjy@chinamobile.com


   Wei Wang
   China Telecom
   32 Xuanwumen West St, Xicheng District
   Beijing
   Email: wangw36@chinatelecom.cn



























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