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Versions: 00 01 02

NETCONF Working Group                                              Q. Wu
Internet-Draft                                                     B. Wu
Intended status: Standards Track                                  Huawei
Expires: January 9, 2021                                          P. Liu
                                                                  H. Cai
                                                            China Mobile
                                                            July 8, 2020


               Self-explanation data Node tag capability
            draft-tao-netconf-notif-node-tag-capabilities-02

Abstract

   Before a client application subscribes to updates from a datastore,
   server capabilities related to "Subscription to YANG Datastores" can
   be advertised using YANG Instance Data format.  These server
   capabilities can be documented at implement time or reported at run-
   time.

   This document proposes a YANG module for self-explanation data Node
   tag capability which augments system capabilities model and provide
   additional self-explanation data node attributes associated with node
   selectors within per-node capabilities.

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 January 9, 2021.

Copyright Notice

   Copyright (c) 2020 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 Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Self-explanation data Node tag capability . . . . . . . . . .   3
     2.1.  Tree Diagram  . . . . . . . . . . . . . . . . . . . . . .   4
   3.  YANG Module . . . . . . . . . . . . . . . . . . . . . . . . .   5
   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  . . . . . . . . . . . . . . . . . .  10
     7.2.  Informative References  . . . . . . . . . . . . . . . . .  11
   Appendix A.  Targeted data object subscription example  . . . . .  11
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  14

1.  Introduction

   As described in [I-D.netconf-notification-capabilities], a server
   supporting YANG-Push MAY have a number of capabilities such as

   o  Supported (reporting) periods for periodic subscriptions;

   o  Maximum number of objects that can be sent in an update;

   o  Supported dampening periods for on-change subscriptions;

   o  The set of data nodes for which on-change notification is
      supported.

   Notification capability model defined in [I-D.netconf-notification-
   capabilities] allows a client to discover basic system capability and
   YANG-Push related capabilities both at implementation-time and run-
   time.  Without using this notification capability, it might lead to
   unexpected failures or additional message exchanges for NETCONF




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   clients to discover data objects with specific capability supported
   by a NETCONF server.

   When all telemetry data on the server subscribed by a particular
   subscriber is huge, it becomes more likely that a burst of streamed
   data may temporarily overwhelm a receiver and consume expensive
   computing and storage resource.  Accordingly, there is a need for
   filtering subscribed telemetry data on a server based on server
   capabilities, which can greatly reduce the amount of data to be
   streamed out to the destination.

   However without telemetry data classification or prior knowledge of
   data objects correlation relationship, it is difficult for NETCONF
   clients to automatically select target data objects that are of
   interest to the client applications, e.g., identify a set of objects
   from different YANG data modules which have a common characteristic,
   collect specific object type nodes for multiple dimensional network
   visibility analysis.

   This document proposes a YANG module for self-explanation data Node
   tag capability which augments System Capabilities model and provide
   additional self-explanation data node tag attributes associated with
   node selector for queries filtering.

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.  Self-explanation data Node tag capability

   The YANG module ietf-notification-capabilities defined in [I-
   D.netconf-notification-capabilities] specifies the following server
   capabilities related to YANG Push:

   o  A set of capabilities related to the amount of notifications the
      server can send out

   o  Specification of which data nodes support on-change notifications.

   o  Capability values can be specified on server level, datastore
      level or on specific data nodes (and their contained sub-tree) of
      a specific datastore.  Capability values on a smaller, more
      specific part of the server's data always override more generic
      values.



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   o  On-change capability is not specified on a server level as
      different datastores usually have different on-change
      capabilities.  On a datastore level on-change capability for
      configuration and state data can be specified separately.

   These server capabilities can be provided either at implementation
   time or reported at run time.

   This document augments system capabilities model and provide
   additional data node self explaination tag attributes associated with
   node selector within per-node capabilities:

   o  Specification of which object type nodes, which performance metric
      nodes, which property related nodes they can push to the target
      recipient;

   o  Specification of measurement precision or granularity associated
      with performance metric related data nodes;

   o  Specification of operation type associated with performance metric
      related data nodes;

   o  Specification of service classification information associated
      with data nodes;

   o  Specification of task group information associated with a set of
      data nodes;

   o  Specification of self tag name of a set of data nodes they can
      push to the target recipient.

   o  Specification of data source type associated with a set of data
      nodes;

   o  Specfication of multi-source aggregation assocaited with a set of
      data nodes;

2.1.  Tree Diagram

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










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    module: ietf-self-explanation-capabilities
    augment /sysc:system-capabilities/sysc:datastore-capabilities/ +
          sysc:per-node-capabilities/sys:node-selection/sys:node-selector:
       +--ro self-describing-attributes* [self-tag-id]
           +--ro self-tag-id             string
           +--ro opm-tag                 tags:tag
           +--ro metric-precision        tags:tag
           +--ro metric-scale            tags:tag
           +--ro operation-type          tags:tag
           +--ro service-tag*            tags:tag
           +--ro task-tag*               tags:tag
           +--ro data-source             tags:tag
           +--ro muli-source-tag         tags:tag

3.  YANG Module

<CODE BEGINS> file "ietf-self-explanation-capabilities.yang"
module ietf-self-explanation-capabilities {
  yang-version 1.1;
  namespace urn:ietf:params:xml:ns:yang:ietf-self-explanation-capabilities;
  prefix sec;
  import ietf-system-capabilities  { prefix sysc ; }
  import ietf-module-tags  { prefix tags; }
  organization
    "IETF NETMOD (Network Modeling) 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>
               Bo Wu
               <mailto:lana.wubo@huawei.com";
  description
    "This module defines an extension to System Capabilities model
     and provides additional self explaination data node tag attributes
     associated with node selector for queries filtering.

     Copyright (c) 2020 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 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).




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     This version of this YANG module is part of RFC XXXX;
     see the RFC itself for full legal notices.";
         revision 2020-07-08 {
    description
      "Initial revision";
    reference
      "RFC XXXX";
  }
    augment "/sysc:system-capabilities/sysc:datastore-capabilities" +
         "/sysc:per-node-capabilities" +
          "/sysc:node-selection/sysc:node-selector" {
     description "Allows per-node capabilities have additional self-explanation attributes";
     list self-describing-attributes {
      key self-tag-id;
      description "self describing attributes for each data node.";
       leaf self-tag-id {
         type string;
         description
          "This self tag id is used to uniquely identify a set of data nodes
          of the same group which have a common characteristic. If the opm-tag
          is metric, self-tag-id represents specific metric name. If the opm-tag
          is metric-group, self-tag-id represents specific metric group name.";
       }
         leaf opm-tag {
           type tags:tag ;
           description
            "Object, Property and Metric(OPM) Tags associated with
            the data node within YANG module.
            See the IANA 'YANG Data Node Tag Prefixes' registry
            for reserved prefixes and the IANA
            'IETF YANG Data Node Tags' registry for IETF tags.";
       }
         leaf metric-precision {
           type tags:tag;
           description
             "The numeric expression precision of performance
              metric related data node.";
         }

        leaf metric-scale {
            type tags:tag;
            description
             "The measurement scale of performance
              metric related data node.";
         }
         leaf operation-type{
          type tags:tag;
          description



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           "Statistics operation of performance metric related
           data node.If the operation type is threshold type, the corresponding
           data object support threshold handling,e.g.,scan all interfaces
            for a certain type every 5 seconds and check the counters or
           status to cross threshold, return an array of interface entries
           that match the search.If the operation type is average,min,max, sum,
           it indicate the data object supports statistics operation, e.g.,
           scan all interfaces for a certain type every 5 seconds up to 60 seconds,
           only return min, average, max, sum value of specific data object rather than
           the values that are current at the end of 60 seconds.";
         }
         leaf-list service-tag {
          type tags:tag;
          description
           "The node-service-tag can be used to provide a service
           classification information (e.g., tunnel, l3vpn,l2vpn)
           information associated with YANG data node.";
         }
         leaf-list task-tag {
          type tags:tag;
          description
           "The node-task-tag can be used to provide a task
           classification information (e.g., fault management,
           performance measurement) information associated with
           YANG data node.";
         }
         leaf data-source {
          type tags:tag;
          description
           "The data source type can be used to identify different
            data source type(e.g., service flow, resource, policy,
            qos, hardware).";
         }
         leaf multi-source-tag {
          type tags:tag;
          description
           "The multiple source tag can be used to aggregate peformance
            metric from different sources.";
         }
     }
   }
}
<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-self-explanation-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-self-explanation-capabilities
     namespace:
        urn:ietf:params:xml:ns:yang:ietf-self-explanation-capabilities
     prefix:
        sec
     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.

   There are a number of data nodes defined in this YANG module that are
   writable/creatable/deletable (i.e., config true, which is the



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   default).  These data nodes may be considered sensitive in some
   network environments.  Write operations (e.g., edit-config) to these
   data nodes without proper protection can have a negative effect on
   network operations.  These are the subtrees and data nodes and their
   sensitivity/vulnerability:

   o  /sysc:system-capabilities/sysc:datastore-capabilities/sysc:per-
      node-capabilities/sys:node-selection/sys:node-selector/sec:self-
      describing-attributes/sec:self-tag-id

   o  /sysc:system-capabilities/sysc:datastore-capabilities/sysc:per-
      node-capabilities/sys:node-selection/sys:node-selector/sec:self-
      describing-attributes/sec:opm-tag

   o  /sysc:system-capabilities/sysc:datastore-capabilities/sysc:per-
      node-capabilities/sys:node-selection/sys:node-selector/sec:self-
      describing-attributes/sec:metric-precision

   o  /sysc:system-capabilities/sysc:datastore-capabilities/sysc:per-
      node-capabilities/sys:node-selection/sys:node-selector/sec:self-
      describing-attributes/sec:operation-type

   o  /sysc:system-capabilities/sysc:datastore-capabilities/sysc:per-
      node-capabilities/sys:node-selection/sys:node-selector/sec:self-
      describing-attributes/sec:service-tag

   o  /sysc:system-capabilities/sysc:datastore-capabilities/sysc:per-
      node-capabilities/sys:node-selection/sys:node-selector/sec:self-
      describing-attributes/sec:task-tag

   o  /sysc:system-capabilities/sysc:datastore-capabilities/sysc:per-
      node-capabilities/sys:node-selection/sys:node-selector/sec:self-
      describing-attributes/sec:data-source

   o  /sysc:system-capabilities/sysc:datastore-capabilities/sysc:per-
      node-capabilities/sys:node-selection/sys:node-selector/sec:self-
      describing-attributes/sec:multi-source-tag

6.  Contributors

   The authors would like to thank Ran Tao for his major contributions
   to the initial modeling and use cases.

7.  References







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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>.

   [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>.




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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>.

7.2.  Informative 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>.

Appendix A.  Targeted data object subscription example

   The following subsections provides targeted data object subscription
   example.The subscription "id" values of 22 used below is just an
   example.  In production, the actual values of "id" might not be small
   integers.


























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    +-----------+                       +-----------+
    | Subscriber|                       | Publisher |
    +------+----+                       +-----+-----+
           |                                  |
           |                                  |
           |Telemery data Tagging Advertisement
           |  (node-selector, opm-tag = metric)
           |<---------------------------------|
           |                                  |
           |    establish-subscription        |
           |  (datasore,node-selector)        |
           |--------------------------------->|
           |                                  |
           |                                  |
           |                                  |
           |    RPC Reply: OK, id = 22        |
           |<---------------------------------|
           |                                  |
           |                                  |
           |                                  |
           |    Notification Message (for 22) |
           | <--------------------------------|
           |                                  |
           |                                  |
           |                                  |

   The publisher advertise telemetry data node capability to the
   subscriber to instruct the receiver to subscribe targeted data object
   with specific characteristics (e.g., performance metric related data
   object) and specific data path corresponding to the targeted data
   object.

   The following XML example [W3C.REC-xml-20081126] illustrates the
   advertisment of the list of available target objects:

















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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>Defines the notification capabilities of an acme-router.
    The router only has running, and operational datastores.
    Every change can be reported on-change from running, but
    only config=true nodes and some config=false data from operational.
    Statistics are not reported based on timer based trigger and counter
    threshold based trigger.
  </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">
      <datastore-capabilities>
        <datastore>ds:operational</datastore>
        <per-node-capabilities>
          <node-selector>\
              /if:interfaces/if:interface/if:statistics/if:in-errors\
          </node-selector>
          <sec:self-describing-capabilities>
            <sec:self-tag-id>bandwith</sec:self-tag-id>
            <sec:opm-tag>metric</sec:opm-tag>
          </sec:self-describing-capabilities>
        </per-node-capabilities>
      </datastore-capabilities>
    </system-capabilities>
  </content-data>
</instance-data-set>

   With telemetry data tagging information carried in the Telemetry data
   Tagging Advertisement, the subscriber identifies targeted data object
   and associated data path to the datastore node and sends a establish-
   subscription RPC to subscribe specific data objects that are
   interests to the client application from the publisher.







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 <netconf:rpc message-id="101"
     xmlns:netconf="urn:ietf:params:xml:ns:netconf:base:1.0">
   <establish-subscription
       xmlns="urn:ietf:params:xml:ns:yang:ietf-subscribed-notifications"
       xmlns:yp="urn:ietf:params:xml:ns:yang:ietf-yang-push">
     <yp:datastore
          xmlns:ds="urn:ietf:params:xml:ns:yang:ietf-datastores">
       ds:operational
     </yp:datastore>
     <yp:datastore-xpath-filter
         xmlns:ex="https://example.com/sample-data/1.0">
       /if:interfaces/if:interface/if:statistics/if:in-errors
     </yp:datastore-xpath-filter>
     <yp:periodic>
       <yp:period>500</yp:period>
     </yp:periodic>
   </establish-subscription>
 </netconf:rpc>

   The publisher returns specific object type of operational state
   related to the subscriber.

Authors' Addresses

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

   Email: bill.wu@huawei.com


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

   Email: lana.wubo@huawei.com


   Peng Liu
   China Mobile
   32 Xuanwumen West St, Xicheng District
   Beijing  10053

   Email: liupengyjy@chinamobile.com



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   Hui Cai
   China Mobile
   32 Xuanwumen West St, Xicheng District
   Beijing  10053

   Email: caihui@chinamobile.com













































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