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<rfc xmlns:xi="http://www.w3.org/2001/XInclude" ipr="trust200902" docName="draft-ietf-ivy-network-inventory-topology-02" category="std" consensus="true" submissionType="IETF" tocInclude="true" sortRefs="true" symRefs="true" version="3">
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  <front>
    <title abbrev="Network Inventory Topology">A Network Data Model for Inventory Topology Mapping</title>
    <seriesInfo name="Internet-Draft" value="draft-ietf-ivy-network-inventory-topology-02"/>
    <author fullname="Bo Wu" role="editor">
      <organization>Huawei</organization>
      <address>
        <email>lana.wubo@huawei.com</email>
      </address>
    </author>
    <author fullname="Mohamed Boucadair">
      <organization>Orange</organization>
      <address>
        <email>mohamed.boucadair@orange.com</email>
      </address>
    </author>
    <author fullname="Cheng Zhou">
      <organization>China Mobile</organization>
      <address>
        <email>zhouchengyjy@chinamobile.com</email>
      </address>
    </author>
    <author fullname="Qin Wu">
      <organization>Huawei</organization>
      <address>
        <email>bill.wu@huawei.com</email>
      </address>
    </author>
    <date year="2025" month="April" day="10"/>
    <area>Operations and Management</area>
    <workgroup>Network Inventory YANG</workgroup>
    <keyword>Automation</keyword>
    <keyword>Network Digital Map</keyword>
    <keyword>Network Inventory</keyword>
    <keyword>Network Operation</keyword>
    <keyword>Network Topology</keyword>
    <abstract>
      <?line 54?>

<t>This document defines a YANG model to
   map the network inventory data with the topology model
   to form a base underlay network. The model facilitates the
   correlation between the layer (e.g.,  Layer 2 and Layer 3) topology information
   and the inventory data of the underlay network for better service
   provisioning, network maintenance operations, and other assessment scenarios.</t>
    </abstract>
    <note removeInRFC="true">
      <name>Discussion Venues</name>
      <t>Discussion of this document takes place on the
    Network Inventory YANG Working Group mailing list (inventory-yang@ietf.org),
    which is archived at <eref target="https://mailarchive.ietf.org/arch/browse/inventory-yang/"/>.</t>
      <t>Source for this draft and an issue tracker can be found at
    <eref target="https://github.com/ietf-ivy-wg/network-inventory-topology"/>.</t>
    </note>
  </front>
  <middle>
    <?line 63?>

<section anchor="introduction">
      <name>Introduction</name>
      <t><xref target="I-D.ietf-ivy-network-inventory-yang"/> defines the base network inventory
  model to aggregate the inventory data of Network Elements (NEs). This data includes identification of these NEs and their hardware,
  firmware, and software components.  Examples
   of inventory hardware components could be rack, shelf, slot, board,
   or physical port.  Examples of inventory software components could
   be platform Operating System (OS), software-patches, bios, or boot-
   loader <xref target="I-D.ietf-ivy-network-inventory-software"/>.</t>
      <t>In order to ease navigation from/to inventory and network topologies,
this document extends the network topology model <xref target="RFC8345"/> for network
inventory mapping: "ietf-network-inventory-topology" (<xref target="sec-module"/>).  This model provides a mechanism for the correlation with existing
network and topology models, such as "A YANG Network Data Model for Service Attachment Points (SAPs)" <xref target="RFC9408"/>, "A YANG Data Model for Layer 2 Network Topologies" <xref target="RFC8944"/>, and "A YANG Data Model for Layer 3 Topologies" <xref target="RFC8346"/>.</t>
      <t>The network inventory topology mapping data model ("ietf-network-inventory-topology") also provides anchor
points to mount specific device configuration and state information,
e.g.,  Quality of Service (QoS) and Access Control List (ACL) policies, to support configuration
verification of policies at the network level. Further sample uses are discussed in <xref target="sample"/>.</t>
      <t>Similar to the base inventory model  <xref target="I-D.ietf-ivy-network-inventory-yang"/>, the network inventory topology
does not make any assumption about involved network elements and their roles in topologies. As such, the mapping
model can be applied indepent of the network type (optical local loops, access network, core network, etc.) and application.</t>
      <t>The YANG data model in this document conforms to the Network
Management Datastore Architecture (NMDA) defined in <xref target="RFC8342"/>.</t>
      <section anchor="editorial-note-to-be-removed-by-rfc-editor">
        <name>Editorial Note (To be removed by RFC Editor)</name>
        <t>Note to the RFC Editor: This section is to be removed prior to publication.</t>
        <t>This document contains placeholder values that need to be replaced with finalized values at the time of publication. This note summarizes all of the substitutions that are needed.</t>
        <t>Please apply the following replacements:</t>
        <ul spacing="normal">
          <li>
            <t>XXXX --&gt; the assigned RFC number for this I-D</t>
          </li>
          <li>
            <t>AAAA --&gt; the assigned RFC number for <xref target="I-D.ietf-ivy-network-inventory-yang"/></t>
          </li>
        </ul>
      </section>
    </section>
    <section anchor="conventions-and-definitions">
      <name>Conventions and Definitions</name>
      <t>The meanings of the symbols in the YANG tree diagrams are defined in <xref target="RFC8340"/>.</t>
      <t>This document uses terms defined in <xref target="I-D.ietf-ivy-network-inventory-yang"/>.</t>
    </section>
    <section anchor="sample">
      <name>Sample Use Cases of the Data Model</name>
      <section anchor="determine-available-resources-of-service-attachment-points-saps">
        <name>Determine Available Resources of Service Attachment Points (SAPs)</name>
        <t>The inventory topology model can be used as a base to correlate
   underlay information, such as physical port components.  <xref target="nwi-topology-usage"/> exemplifies this usage.</t>
        <t>During service provisioning, to check available physical port
   resources, the SAPs information can be
   associated with the underlay inventory information and interface
   information associated with the inventory topology, e.g.,
   "parent-termination-point" of SAP Model can be associated with the
   "port-component-ref" and "interface-name" of the inventory topology model,
   which can be used to check the availability and capacity of physical
   ports.</t>
        <figure anchor="nwi-topology-usage">
          <name>An Example Usage of Network Inventory Topology</name>
          <artset>
            <artwork type="svg" align="center"><svg xmlns="http://www.w3.org/2000/svg" version="1.1" height="352" width="432" viewBox="0 0 432 352" class="diagram" text-anchor="middle" font-family="monospace" font-size="13px" stroke-linecap="round">
                <path d="M 32,288 L 32,320" fill="none" stroke="black"/>
                <path d="M 136,32 L 136,64" fill="none" stroke="black"/>
                <path d="M 136,112 L 136,160" fill="none" stroke="black"/>
                <path d="M 136,208 L 136,256" fill="none" stroke="black"/>
                <path d="M 192,160 L 192,208" fill="none" stroke="black"/>
                <path d="M 208,64 L 208,112" fill="none" stroke="black"/>
                <path d="M 208,256 L 208,288" fill="none" stroke="black"/>
                <path d="M 224,160 L 224,208" fill="none" stroke="black"/>
                <path d="M 280,32 L 280,64" fill="none" stroke="black"/>
                <path d="M 280,112 L 280,160" fill="none" stroke="black"/>
                <path d="M 280,208 L 280,256" fill="none" stroke="black"/>
                <path d="M 384,288 L 384,320" fill="none" stroke="black"/>
                <path d="M 136,32 L 280,32" fill="none" stroke="black"/>
                <path d="M 136,64 L 280,64" fill="none" stroke="black"/>
                <path d="M 136,112 L 280,112" fill="none" stroke="black"/>
                <path d="M 136,160 L 280,160" fill="none" stroke="black"/>
                <path d="M 136,208 L 280,208" fill="none" stroke="black"/>
                <path d="M 136,256 L 280,256" fill="none" stroke="black"/>
                <path d="M 32,288 L 384,288" fill="none" stroke="black"/>
                <path d="M 32,320 L 384,320" fill="none" stroke="black"/>
                <g class="text">
                  <text x="212" y="52">Customer</text>
                  <text x="36" y="84">Customer</text>
                  <text x="104" y="84">Service</text>
                  <text x="164" y="84">Models</text>
                  <text x="52" y="100">(e.g.,</text>
                  <text x="104" y="100">L3SM,</text>
                  <text x="152" y="100">L2SM)</text>
                  <text x="200" y="132">Service</text>
                  <text x="208" y="148">Orchestration</text>
                  <text x="56" y="196">SAP</text>
                  <text x="104" y="196">Network</text>
                  <text x="160" y="196">Model</text>
                  <text x="272" y="196">Inventory</text>
                  <text x="348" y="196">Topology</text>
                  <text x="408" y="196">Model</text>
                  <text x="208" y="228">Network</text>
                  <text x="204" y="244">Controller</text>
                  <text x="208" y="308">Network</text>
                </g>
              </svg>
            </artwork>
            <artwork type="ascii-art" align="center"><![CDATA[
                        +-----------------+
                        |     Customer    |
                        +--------+--------+
        Customer Service Models  |
           (e.g., L3SM, L2SM)    |
                        +--------+--------+
                        |    Service      |
                        |  Orchestration  |
                        +------+---+------+
                               |   |
             SAP Network Model |   | Inventory Topology Model
                        +------+---+------+
                        |     Network     |
                        |   Controller    |
                        +--------+--------+
                                 |
           +---------------------+---------------------+
           |                  Network                  |
           +-------------------------------------------+
]]></artwork>
          </artset>
        </figure>
      </section>
      <section anchor="what-if-scenarios">
        <name>"What-if" Scenarios</name>
        <t><xref target="I-D.irtf-nmrg-network-digital-twin-arch"/> defines Network Digital Twin (NDT)
   as a virtual representation of the physical network.  Such
    representation is meant to be used to analyze,
   diagnose, emulate, and then manage the physical network based on
   data, models, and interfaces.</t>
        <t>The management system can use NDT to build
   multi-layer topology maps for networks and endpoints with
   relationship types and dependencies, and identify potential impacts
   on configuration management information from incidents, problems, and
   changes. More generally, the inventory topology model can be used as part of the SIMAP <xref target="I-D.ietf-nmop-simap-concept"/>.</t>
        <t>The inventory topology model can, for example, be used to emulate
   several "what-if" scenarios such as the impact of End of Life (EOL) or depletion of a
   hardware component (chipset) on the network resilience and service
   availability.</t>
      </section>
    </section>
    <section anchor="module-tree-structure">
      <name>Module Tree Structure</name>
      <t>An overview of the structure of the "ietf-network-inventory-topology" module is shown in <xref target="tree"/>.</t>
      <figure anchor="tree">
        <name>The Structure of the Network Inventory Mapping Data Model</name>
        <artwork align="center"><![CDATA[
module: ietf-network-inventory-topology
  augment /nw:networks/nw:network/nw:node:
    +--rw inventory-mapping-attributes
            {topology-to-inventory-navigate}?
       +--ro ne-ref?   nwi:ne-ref
  augment /nw:networks/nw:network/nt:link:
    +--rw inventory-mapping-attributes
            {topology-to-inventory-navigate}?
       +--ro cable-name?   string
       +--ro link-type?    string
  augment /nw:networks/nw:network/nw:node/nt:termination-point:
    +--rw inventory-mapping-attributes
            {topology-to-inventory-navigate}?
       +--rw ne-ref?                    nwi:ne-ref
       +--rw port-ref?                  leafref
       +--ro physical-interface-name?   string
  augment /nwi:network-inventory/nwi:network-elements
            /nwi:network-element:
    +--rw node-ref?      leafref {inventory-to-topology-navigate}?
    +--rw network-ref?   -> /nw:networks/network/network-id
            {inventory-to-topology-navigate}?
]]></artwork>
      </figure>
      <t>The module defines two features "inventory-to-topology-navigate" and "topology-to-inventory-navigate"
to control the navigation direction (from topology to inventory and vice versa).</t>
      <t>The module augments the "ietf-network-topology" module as follows:</t>
      <ul spacing="normal">
        <li>
          <t>A new network topology type: "network-inventory-mapping".  The
      corresponding container augments the "network-types" of the "ietf-network" module.</t>
        </li>
        <li>
          <t>Inventory mapping attributes for nodes, links, and termination
      points: The corresponding containers augments the topology module
      with the references to the base network inventory, references to
      interface management, and policy mount points  </t>
          <t>
The inventory topology
 model associates inventory data with overlay topologies.  It can be
 used as the "supporting-networks" of SAP, Layer 2, or Layer 3
 topologies.</t>
        </li>
      </ul>
      <t>Also, the "ietf-network-inventory-topology" module augments the "ietf-network-inventory" to add
required references to navigate from the inventory to topologies ('node-ref' and 'network-ref').</t>
    </section>
    <section anchor="sec-module">
      <name>Network Inventory Topology YANG Module</name>
      <t>This module augments the Network Topology <xref target="RFC8345"/>.</t>
      <t>This module imports the base network inventory <xref target="I-D.ietf-ivy-network-inventory-yang"/>.</t>
      <sourcecode type="yang" markers="true" name="ietf-network-inventory-topology@2025-02-04.yang"><![CDATA[
module ietf-network-inventory-topology {
  yang-version 1.1;
  namespace
    "urn:ietf:params:xml:ns:yang:ietf-network-inventory-topology";
  prefix nwit;

  import ietf-network {
    prefix nw;
    reference
      "RFC 8345: A YANG Data Model for Network Topologies,
                 Section 4.1";
  }
  import ietf-network-topology {
    prefix nt;
    reference
      "RFC 8345: A YANG Data Model for Network Topologies,
                 Section 4.2";
  }
  import ietf-network-inventory {
    prefix nwi;
    reference
      "RFC AAAA: A YANG Data Model for Network Inventory";
  }

  organization
    "IETF Network Inventory YANG (ivy) Working Group";
  contact
    "WG Web:   <https://datatracker.ietf.org/wg/ivy>
     WG List:  <mailto:inventory-yang@ietf.org>

     Editor: Bo Wu
             <lana.wubo@huawei.com>
     Editor: Mohamed Boucadair
             <mohamed.boucadair@orange.com>
     Author: Cheng Zhou
             <zhouchengyjy@chinamobile.com>
     Author: Qin Wu
             <bill.wu@huawei.com>";
  description
    "This YANG module defines a YANG module for network
     topology and inventory mapping.

     Copyright (c) 2025 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
     (https://www.rfc-editor.org/info/rfcXXXX); see the RFC
     itself for full legal notices.";

  revision 2025-03-03 {
    description
      "Initial revision.";
    reference
      "RFC XXXX: A YANG Data Model for Network Inventory Mapping
                 Topology";
  }

  /* features */

  feature inventory-to-topology-navigate {
    description
      "Indicates support for navigating from inventory to topology.";
  }

  feature topology-to-inventory-navigate {
    description
      "Indicates support for navigating from topology to inventory.";
  }

  /* Groupings */
  /* Node Grouping Feature with 1:1 mapping to NE*/

  grouping node-inventory-feature-attributes {
    description
      "Network Inventory mapping node scope attributes";
    container inventory-mapping-attributes {
      if-feature "topology-to-inventory-navigate";
      description
        "The container node attributes of Network Inventory
         mapping.";
      leaf ne-ref {
        type nwi:ne-ref;
        config false;
        description
          "1:1 mapping to the Network Element (NE) from which this
           node is abstracted.";
      }
    }
  }

  grouping tp-inventory-feature-attributes {
    description
      "Network Inventory mapping Termination Point (TP) scope
       attributes";
    container inventory-mapping-attributes {
      if-feature "topology-to-inventory-navigate";
      description
        "Specifies the TP attributes of Network Inventory mapping.";
      /* 1:1 mapping to physical port component */
      uses nwi:port-ref;
      leaf physical-interface-name {
        type string;
        config false;
        description
          "1:1 mapping to physical interface name (e.g., eth0/1)";
      }
    }
  }

  grouping link-inventory-feature-attributes {
    description
      "Network Inventory mapping link scope attributes.";
    container inventory-mapping-attributes {
      if-feature "topology-to-inventory-navigate";
      description
        "Specifies  the link attributes of network inventory
         mapping.";
      leaf cable-name {
        type string;
        config false;
        description
          "Reports the reference of the cable inventory from which
           this link is abstracted.";
      }
      leaf link-type {
        type string;
        config false;
        description
          "Reports the type of the link.";
      }
    }
  }

  /* Main blocks */

  augment "/nw:networks/nw:network/nw:node" {
    description
      "Groups parameters for inventory at the node level.";
    uses node-inventory-feature-attributes;
  }

  augment "/nw:networks/nw:network/nt:link" {
    description
      "Augments inventory topology link information.";
    uses link-inventory-feature-attributes;
  }

  augment "/nw:networks/nw:network/nw:node/nt:termination-point" {
    description
      "Augments inventory termination point information.";
    uses tp-inventory-feature-attributes;
  }

  /* Augment the network-inventory to add 
     topology navigate */

  augment "/nwi:network-inventory/nwi:network-elements"
        + "/nwi:network-element" {
    if-feature "inventory-to-topology-navigate";
    description
      "Augments the network element with 1:1 mapping with the network
          the element is part of.";
    uses nw:node-ref;
  }
}

]]></sourcecode>
    </section>
    <section anchor="security-considerations">
      <name>Security Considerations</name>
      <t>This section is modeled after the template described in <xref section="3.7" sectionFormat="of" target="I-D.ietf-netmod-rfc8407bis"/>.</t>
      <t>The "ietf-network-inventory-topology" YANG module defines a data model that is
designed to be accessed via YANG-based management protocols, such as
NETCONF <xref target="RFC6241"/> and RESTCONF <xref target="RFC8040"/>. These protocols have to
use a secure transport layer (e.g., SSH <xref target="RFC4252"/>, TLS <xref target="RFC8446"/>, and
QUIC {{?RFC9000]) and have to use mutual authentication.</t>
      <t>The Network Configuration Access Control Model (NACM) <xref target="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.</t>
      <t>There are a number of data nodes defined in this YANG module that are
writable/creatable/deletable (i.e., "config true", which is the
default).  All writable data nodes are likely to be reasonably
sensitive or vulnerable in some network environments.  Write
operations (e.g., edit-config) and delete operations to these data
nodes without proper protection or authentication can have a negative
effect on network operations.  The following subtrees and data nodes
have particular sensitivities/vulnerabilities:</t>
      <t>Some of the readable data nodes in this YANG module may be considered
   sensitive or vulnerable in some network environments.  It is thus
   important to control read access (e.g., via get, get-config, or
   notification) to these data nodes.  Specifically, the following
subtrees and data nodes have particular sensitivities/vulnerabilities:</t>
      <dl>
        <dt>'ne-ref':</dt>
        <dd>
          <t>The reference may be used to track the set of network elements.</t>
        </dd>
      </dl>
    </section>
    <section anchor="iana-considerations">
      <name>IANA Considerations</name>
      <t>IANA is requested to register the following URI in the "ns" subregistry within
   the "IETF XML Registry" <xref target="RFC3688"/>:</t>
      <artwork><![CDATA[
   URI:  urn:ietf:params:xml:ns:yang:ietf-network-inventory-topology
   Registrant Contact:  The IESG.
   XML:  N/A; the requested URI is an XML namespace.
]]></artwork>
      <t>IANA is requested to register the following YANG module in the "YANG Module
   Names" registry <xref target="RFC6020"/> within the "YANG Parameters" registry group:</t>
      <artwork><![CDATA[
   Name:  ietf-network-inventory-topology
   Namespace:  urn:ietf:params:xml:ns:yang:ietf-network-inventory-topology
   Prefix:  nwit
   Maintained by IANA?  N
   Reference:  RFC XXXX
]]></artwork>
    </section>
  </middle>
  <back>
    <references anchor="sec-combined-references">
      <name>References</name>
      <references anchor="sec-normative-references">
        <name>Normative References</name>
        <reference anchor="I-D.ietf-ivy-network-inventory-yang">
          <front>
            <title>A Base YANG Data Model for Network Inventory</title>
            <author fullname="Chaode Yu" initials="C." surname="Yu">
              <organization>Huawei Technologies</organization>
            </author>
            <author fullname="Sergio Belotti" initials="S." surname="Belotti">
              <organization>Nokia</organization>
            </author>
            <author fullname="Jean-Francois Bouquier" initials="J." surname="Bouquier">
              <organization>Vodafone</organization>
            </author>
            <author fullname="Fabio Peruzzini" initials="F." surname="Peruzzini">
              <organization>TIM</organization>
            </author>
            <author fullname="Phil Bedard" initials="P." surname="Bedard">
              <organization>Cisco</organization>
            </author>
            <date day="28" month="February" year="2025"/>
            <abstract>
              <t>   This document defines a base YANG data model for network inventory.
   The scope of this base model is set to be application- and
   technology-agnostic.  However, the data model is designed with
   appropriate provisions to ease future augmentations with application-
   and technology-specific details.

              </t>
            </abstract>
          </front>
          <seriesInfo name="Internet-Draft" value="draft-ietf-ivy-network-inventory-yang-05"/>
        </reference>
        <reference anchor="RFC8345">
          <front>
            <title>A YANG Data Model for Network Topologies</title>
            <author fullname="A. Clemm" initials="A." surname="Clemm"/>
            <author fullname="J. Medved" initials="J." surname="Medved"/>
            <author fullname="R. Varga" initials="R." surname="Varga"/>
            <author fullname="N. Bahadur" initials="N." surname="Bahadur"/>
            <author fullname="H. Ananthakrishnan" initials="H." surname="Ananthakrishnan"/>
            <author fullname="X. Liu" initials="X." surname="Liu"/>
            <date month="March" year="2018"/>
            <abstract>
              <t>This document defines an abstract (generic, or base) YANG data model for network/service topologies and inventories. The data model serves as a base model that is augmented with technology-specific details in other, more specific topology and inventory data models.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8345"/>
          <seriesInfo name="DOI" value="10.17487/RFC8345"/>
        </reference>
        <reference anchor="RFC9408">
          <front>
            <title>A YANG Network Data Model for Service Attachment Points (SAPs)</title>
            <author fullname="M. Boucadair" initials="M." role="editor" surname="Boucadair"/>
            <author fullname="O. Gonzalez de Dios" initials="O." surname="Gonzalez de Dios"/>
            <author fullname="S. Barguil" initials="S." surname="Barguil"/>
            <author fullname="Q. Wu" initials="Q." surname="Wu"/>
            <author fullname="V. Lopez" initials="V." surname="Lopez"/>
            <date month="June" year="2023"/>
            <abstract>
              <t>This document defines a YANG data model for representing an abstract view of the provider network topology that contains the points from which its services can be attached (e.g., basic connectivity, VPN, network slices). Also, the model can be used to retrieve the points where the services are actually being delivered to customers (including peer networks).</t>
              <t>This document augments the 'ietf-network' data model defined in RFC 8345 by adding the concept of Service Attachment Points (SAPs). The SAPs are the network reference points to which network services, such as Layer 3 Virtual Private Network (L3VPN) or Layer 2 Virtual Private Network (L2VPN), can be attached. One or multiple services can be bound to the same SAP. Both User-to-Network Interface (UNI) and Network-to-Network Interface (NNI) are supported in the SAP data model.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="9408"/>
          <seriesInfo name="DOI" value="10.17487/RFC9408"/>
        </reference>
        <reference anchor="RFC8342">
          <front>
            <title>Network Management Datastore Architecture (NMDA)</title>
            <author fullname="M. Bjorklund" initials="M." surname="Bjorklund"/>
            <author fullname="J. Schoenwaelder" initials="J." surname="Schoenwaelder"/>
            <author fullname="P. Shafer" initials="P." surname="Shafer"/>
            <author fullname="K. Watsen" initials="K." surname="Watsen"/>
            <author fullname="R. Wilton" initials="R." surname="Wilton"/>
            <date month="March" year="2018"/>
            <abstract>
              <t>Datastores are a fundamental concept binding the data models written in the YANG data modeling language to network management protocols such as the Network Configuration Protocol (NETCONF) and RESTCONF. This document defines an architectural framework for datastores based on the experience gained with the initial simpler model, addressing requirements that were not well supported in the initial model. This document updates RFC 7950.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8342"/>
          <seriesInfo name="DOI" value="10.17487/RFC8342"/>
        </reference>
        <reference anchor="RFC8341">
          <front>
            <title>Network Configuration Access Control Model</title>
            <author fullname="A. Bierman" initials="A." surname="Bierman"/>
            <author fullname="M. Bjorklund" initials="M." surname="Bjorklund"/>
            <date month="March" year="2018"/>
            <abstract>
              <t>The standardization of network configuration interfaces for use with the Network Configuration Protocol (NETCONF) or the RESTCONF protocol requires a structured and secure operating environment that promotes human usability and multi-vendor interoperability. There is a need for standard mechanisms to restrict NETCONF or RESTCONF protocol access for particular users to a preconfigured subset of all available NETCONF or RESTCONF protocol operations and content. This document defines such an access control model.</t>
              <t>This document obsoletes RFC 6536.</t>
            </abstract>
          </front>
          <seriesInfo name="STD" value="91"/>
          <seriesInfo name="RFC" value="8341"/>
          <seriesInfo name="DOI" value="10.17487/RFC8341"/>
        </reference>
        <reference anchor="RFC3688">
          <front>
            <title>The IETF XML Registry</title>
            <author fullname="M. Mealling" initials="M." surname="Mealling"/>
            <date month="January" year="2004"/>
            <abstract>
              <t>This document describes an IANA maintained registry for IETF standards which use Extensible Markup Language (XML) related items such as Namespaces, Document Type Declarations (DTDs), Schemas, and Resource Description Framework (RDF) Schemas.</t>
            </abstract>
          </front>
          <seriesInfo name="BCP" value="81"/>
          <seriesInfo name="RFC" value="3688"/>
          <seriesInfo name="DOI" value="10.17487/RFC3688"/>
        </reference>
        <reference anchor="RFC6020">
          <front>
            <title>YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)</title>
            <author fullname="M. Bjorklund" initials="M." role="editor" surname="Bjorklund"/>
            <date month="October" year="2010"/>
            <abstract>
              <t>YANG is a data modeling language used to model configuration and state data manipulated by the Network Configuration Protocol (NETCONF), NETCONF remote procedure calls, and NETCONF notifications. [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="6020"/>
          <seriesInfo name="DOI" value="10.17487/RFC6020"/>
        </reference>
      </references>
      <references anchor="sec-informative-references">
        <name>Informative References</name>
        <reference anchor="I-D.ietf-ivy-network-inventory-software">
          <front>
            <title>A YANG Network Data Model of Network Inventory Software Extensions</title>
            <author fullname="Bo Wu" initials="B." surname="Wu">
              <organization>Huawei</organization>
            </author>
            <author fullname="Cheng Zhou" initials="C." surname="Zhou">
              <organization>China Mobile</organization>
            </author>
            <author fullname="Qin Wu" initials="Q." surname="Wu">
              <organization>Huawei</organization>
            </author>
            <author fullname="Mohamed Boucadair" initials="M." surname="Boucadair">
              <organization>Orange</organization>
            </author>
            <date day="9" month="December" year="2024"/>
            <abstract>
              <t>   The base Network Inventory YANG model defines the physical network
   elements (NEs) and hardware components of NEs.  This document extends
   the base Network Inventory model for non-physical NEs (e.g.,
   controllers, virtual routers, virtual firewalls) and software
   components (e.g., platform operating system (OS), software-patch).

              </t>
            </abstract>
          </front>
          <seriesInfo name="Internet-Draft" value="draft-ietf-ivy-network-inventory-software-00"/>
        </reference>
        <reference anchor="RFC8944">
          <front>
            <title>A YANG Data Model for Layer 2 Network Topologies</title>
            <author fullname="J. Dong" initials="J." surname="Dong"/>
            <author fullname="X. Wei" initials="X." surname="Wei"/>
            <author fullname="Q. Wu" initials="Q." surname="Wu"/>
            <author fullname="M. Boucadair" initials="M." surname="Boucadair"/>
            <author fullname="A. Liu" initials="A." surname="Liu"/>
            <date month="November" year="2020"/>
            <abstract>
              <t>This document defines a YANG data model for Layer 2 network topologies. In particular, this data model augments the generic network and network topology data models with topology attributes that are specific to Layer 2.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8944"/>
          <seriesInfo name="DOI" value="10.17487/RFC8944"/>
        </reference>
        <reference anchor="RFC8346">
          <front>
            <title>A YANG Data Model for Layer 3 Topologies</title>
            <author fullname="A. Clemm" initials="A." surname="Clemm"/>
            <author fullname="J. Medved" initials="J." surname="Medved"/>
            <author fullname="R. Varga" initials="R." surname="Varga"/>
            <author fullname="X. Liu" initials="X." surname="Liu"/>
            <author fullname="H. Ananthakrishnan" initials="H." surname="Ananthakrishnan"/>
            <author fullname="N. Bahadur" initials="N." surname="Bahadur"/>
            <date month="March" year="2018"/>
            <abstract>
              <t>This document defines a YANG data model for Layer 3 network topologies.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8346"/>
          <seriesInfo name="DOI" value="10.17487/RFC8346"/>
        </reference>
        <reference anchor="RFC8340">
          <front>
            <title>YANG Tree Diagrams</title>
            <author fullname="M. Bjorklund" initials="M." surname="Bjorklund"/>
            <author fullname="L. Berger" initials="L." role="editor" surname="Berger"/>
            <date month="March" year="2018"/>
            <abstract>
              <t>This document captures the current syntax used in YANG module tree diagrams. The purpose of this document is to provide a single location for this definition. This syntax may be updated from time to time based on the evolution of the YANG language.</t>
            </abstract>
          </front>
          <seriesInfo name="BCP" value="215"/>
          <seriesInfo name="RFC" value="8340"/>
          <seriesInfo name="DOI" value="10.17487/RFC8340"/>
        </reference>
        <reference anchor="I-D.irtf-nmrg-network-digital-twin-arch">
          <front>
            <title>Network Digital Twin: Concepts and Reference Architecture</title>
            <author fullname="Cheng Zhou" initials="C." surname="Zhou">
              <organization>China Mobile</organization>
            </author>
            <author fullname="Hongwei Yang" initials="H." surname="Yang">
              <organization>China Mobile</organization>
            </author>
            <author fullname="Xiaodong Duan" initials="X." surname="Duan">
              <organization>China Mobile</organization>
            </author>
            <author fullname="Diego Lopez" initials="D." surname="Lopez">
         </author>
            <author fullname="Antonio Pastor" initials="A." surname="Pastor">
         </author>
            <author fullname="Qin Wu" initials="Q." surname="Wu">
              <organization>Huawei</organization>
            </author>
            <author fullname="Mohamed Boucadair" initials="M." surname="Boucadair">
              <organization>Orange</organization>
            </author>
            <author fullname="Christian Jacquenet" initials="C." surname="Jacquenet">
              <organization>Orange</organization>
            </author>
            <date day="28" month="February" year="2025"/>
            <abstract>
              <t>   Digital Twin technology has been seen as a rapid adoption technology
   in Industry 4.0.  The application of Digital Twin technology in the
   networking field is meant to develop various rich network
   applications, realize efficient and cost-effective data-driven
   network management, and accelerate network innovation.

   This document presents an overview of the concepts of Network Digital
   Twin, provides the basic definitions and a reference architecture,
   lists a set of application scenarios, and discusses such technology's
   benefits and key challenges.

              </t>
            </abstract>
          </front>
          <seriesInfo name="Internet-Draft" value="draft-irtf-nmrg-network-digital-twin-arch-10"/>
        </reference>
        <reference anchor="I-D.ietf-nmop-simap-concept">
          <front>
            <title>SIMAP: Concept, Requirements, and Use Cases</title>
            <author fullname="Olga Havel" initials="O." surname="Havel">
              <organization>Huawei</organization>
            </author>
            <author fullname="Benoît Claise" initials="B." surname="Claise">
              <organization>Huawei</organization>
            </author>
            <author fullname="Oscar Gonzalez de Dios" initials="O. G." surname="de Dios">
              <organization>Telefonica</organization>
            </author>
            <author fullname="Thomas Graf" initials="T." surname="Graf">
              <organization>Swisscom</organization>
            </author>
            <date day="3" month="March" year="2025"/>
            <abstract>
              <t>   This document defines the concept of Service &amp; Infrastructure Maps
   (SIMAP) and identifies a set of SIMAP requirements and use cases.
   The SIMAP was previously known as Digital Map.

   The document intends to be used as a reference for the assessment of
   the various topology modules to meet SIMAP requirements.

              </t>
            </abstract>
          </front>
          <seriesInfo name="Internet-Draft" value="draft-ietf-nmop-simap-concept-03"/>
        </reference>
        <reference anchor="I-D.ietf-netmod-rfc8407bis">
          <front>
            <title>Guidelines for Authors and Reviewers of Documents Containing YANG Data Models</title>
            <author fullname="Andy Bierman" initials="A." surname="Bierman">
              <organization>YumaWorks</organization>
            </author>
            <author fullname="Mohamed Boucadair" initials="M." surname="Boucadair">
              <organization>Orange</organization>
            </author>
            <author fullname="Qin Wu" initials="Q." surname="Wu">
              <organization>Huawei</organization>
            </author>
            <date day="14" month="January" year="2025"/>
            <abstract>
              <t>   This memo provides guidelines for authors and reviewers of
   specifications containing YANG modules, including IANA-maintained
   modules.  Recommendations and procedures are defined, which are
   intended to increase interoperability and usability of Network
   Configuration Protocol (NETCONF) and RESTCONF protocol
   implementations that utilize YANG modules.  This document obsoletes
   RFC 8407.

   Also, this document updates RFC 8126 by providing additional
   guidelines for writing the IANA considerations for RFCs that specify
   IANA-maintained modules.  The document also updates RFC 6020 by
   clarifying how modules and their revisions are handled by IANA.

              </t>
            </abstract>
          </front>
          <seriesInfo name="Internet-Draft" value="draft-ietf-netmod-rfc8407bis-22"/>
        </reference>
        <reference anchor="RFC6241">
          <front>
            <title>Network Configuration Protocol (NETCONF)</title>
            <author fullname="R. Enns" initials="R." role="editor" surname="Enns"/>
            <author fullname="M. Bjorklund" initials="M." role="editor" surname="Bjorklund"/>
            <author fullname="J. Schoenwaelder" initials="J." role="editor" surname="Schoenwaelder"/>
            <author fullname="A. Bierman" initials="A." role="editor" surname="Bierman"/>
            <date month="June" year="2011"/>
            <abstract>
              <t>The Network Configuration Protocol (NETCONF) defined in this document provides mechanisms to install, manipulate, and delete the configuration of network devices. It uses an Extensible Markup Language (XML)-based data encoding for the configuration data as well as the protocol messages. The NETCONF protocol operations are realized as remote procedure calls (RPCs). This document obsoletes RFC 4741. [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="6241"/>
          <seriesInfo name="DOI" value="10.17487/RFC6241"/>
        </reference>
        <reference anchor="RFC8040">
          <front>
            <title>RESTCONF Protocol</title>
            <author fullname="A. Bierman" initials="A." surname="Bierman"/>
            <author fullname="M. Bjorklund" initials="M." surname="Bjorklund"/>
            <author fullname="K. Watsen" initials="K." surname="Watsen"/>
            <date month="January" year="2017"/>
            <abstract>
              <t>This document describes an HTTP-based protocol that provides a programmatic interface for accessing data defined in YANG, using the datastore concepts defined in the Network Configuration Protocol (NETCONF).</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8040"/>
          <seriesInfo name="DOI" value="10.17487/RFC8040"/>
        </reference>
        <reference anchor="RFC4252">
          <front>
            <title>The Secure Shell (SSH) Authentication Protocol</title>
            <author fullname="T. Ylonen" initials="T." surname="Ylonen"/>
            <author fullname="C. Lonvick" initials="C." role="editor" surname="Lonvick"/>
            <date month="January" year="2006"/>
            <abstract>
              <t>The Secure Shell Protocol (SSH) is a protocol for secure remote login and other secure network services over an insecure network. This document describes the SSH authentication protocol framework and public key, password, and host-based client authentication methods. Additional authentication methods are described in separate documents. The SSH authentication protocol runs on top of the SSH transport layer protocol and provides a single authenticated tunnel for the SSH connection protocol. [STANDARDS-TRACK]</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="4252"/>
          <seriesInfo name="DOI" value="10.17487/RFC4252"/>
        </reference>
        <reference anchor="RFC8446">
          <front>
            <title>The Transport Layer Security (TLS) Protocol Version 1.3</title>
            <author fullname="E. Rescorla" initials="E." surname="Rescorla"/>
            <date month="August" year="2018"/>
            <abstract>
              <t>This document specifies version 1.3 of the Transport Layer Security (TLS) protocol. TLS allows client/server applications to communicate over the Internet in a way that is designed to prevent eavesdropping, tampering, and message forgery.</t>
              <t>This document updates RFCs 5705 and 6066, and obsoletes RFCs 5077, 5246, and 6961. This document also specifies new requirements for TLS 1.2 implementations.</t>
            </abstract>
          </front>
          <seriesInfo name="RFC" value="8446"/>
          <seriesInfo name="DOI" value="10.17487/RFC8446"/>
        </reference>
      </references>
    </references>
    <?line 456?>

<section numbered="false" anchor="acknowledgments">
      <name>Acknowledgments</name>
      <t>The authors wish to thank Italo Busi, Olga Havel, Aihua Guo, Oscar
   Gonzalez de Dios, and many others for their helpful comments and
   suggestions.</t>
    </section>
    <section anchor="contributors" numbered="false" toc="include" removeInRFC="false">
      <name>Contributors</name>
      <contact fullname="Chaode Yu">
        <organization>Huawei</organization>
        <address>
          <email>yuchaode@huawei.com</email>
        </address>
      </contact>
    </section>
  </back>
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