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A Base YANG Data Model for Network Inventory
draft-ietf-ivy-network-inventory-yang-11

Document Type Active Internet-Draft (ivy WG)
Authors Chaode Yu , Sergio Belotti , Jean-Francois Bouquier , Fabio Peruzzini , Phil Bedard
Last updated 2025-11-06 (Latest revision 2025-10-14)
Replaces draft-y3bp-ivy-network-inventory-yang
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draft-ietf-ivy-network-inventory-yang-11
Network Working Group                                              C. Yu
Internet-Draft                                       Huawei Technologies
Intended status: Standards Track                              S. Belotti
Expires: 17 April 2026                                             Nokia
                                                          J.-F. Bouquier
                                                                Vodafone
                                                            F. Peruzzini
                                                                FiberCop
                                                               P. Bedard
                                                                   Cisco
                                                         14 October 2025

              A Base YANG Data Model for Network Inventory
                draft-ietf-ivy-network-inventory-yang-11

Abstract

   This document defines a base YANG data model for reporting network
   inventory.  The scope of this base model is set to be application-
   and technology-agnostic.  The base data model can be augmented with
   application- and technology-specific details.

About This Document

   This note is to be removed before publishing as an RFC.

   The latest revision of this draft can be found at https://ietf-ivy-
   wg.github.io/network-inventory-yang/draft-ietf-ivy-network-inventory-
   yang.html.  Status information for this document may be found at
   https://datatracker.ietf.org/doc/draft-ietf-ivy-network-inventory-
   yang/.

   Source for this draft and an issue tracker can be found at
   https://github.com/ietf-ivy-wg/network-inventory-yang.

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/.

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   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 17 April 2026.

Copyright Notice

   Copyright (c) 2025 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Editorial Note (To be removed by RFC Editor)  . . . . . .   4
   2.  Terminology and Notations . . . . . . . . . . . . . . . . . .   5
     2.1.  Requirements Notations  . . . . . . . . . . . . . . . . .   5
     2.2.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   5
     2.3.  Tree Diagrams . . . . . . . . . . . . . . . . . . . . . .   7
     2.4.  YANG Prefixes . . . . . . . . . . . . . . . . . . . . . .   7
   3.  YANG Data Model for Network Inventory Overview  . . . . . . .   7
     3.1.  Common attributes for inventory object  . . . . . . . . .   9
       3.1.1.  Common attributes for network elements and
               components  . . . . . . . . . . . . . . . . . . . . .   9
     3.2.  Network Element . . . . . . . . . . . . . . . . . . . . .  10
     3.3.  Components  . . . . . . . . . . . . . . . . . . . . . . .  10
       3.3.1.  Hardware Components . . . . . . . . . . . . . . . . .  11
       3.3.2.  Software Components . . . . . . . . . . . . . . . . .  12
     3.4.  Changes Since RFC 8348  . . . . . . . . . . . . . . . . .  13
       3.4.1.  Part Number . . . . . . . . . . . . . . . . . . . . .  13
       3.4.2.  Component identifiers . . . . . . . . . . . . . . . .  13
   4.  Network Inventory Tree Diagram  . . . . . . . . . . . . . . .  14
   5.  YANG Data Model for Network Inventory . . . . . . . . . . . .  16
   6.  Operational Considerations  . . . . . . . . . . . . . . . . .  25
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  26
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  27
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  27
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .  27

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     9.2.  Informative References  . . . . . . . . . . . . . . . . .  29
   Appendix A.  Comparison With Openconfig-platform Data Model . . .  31
   Appendix B.  Terminology of Container . . . . . . . . . . . . . .  34
   Appendix C.  Efficiency Issue . . . . . . . . . . . . . . . . . .  34
   Appendix D.  Examples of ports  . . . . . . . . . . . . . . . . .  35
     D.1.  JSON Examples . . . . . . . . . . . . . . . . . . . . . .  36
   Appendix E.  Example of multi-chassis network elements  . . . . .  37
     E.1.  JSON Examples . . . . . . . . . . . . . . . . . . . . . .  41
   Appendix F.  Example of non-modular network elements  . . . . . .  52
     F.1.  JSON Examples . . . . . . . . . . . . . . . . . . . . . .  53
   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .  55
   Contributors  . . . . . . . . . . . . . . . . . . . . . . . . . .  56
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  56

1.  Introduction

   This document defines a base YANG data model for reporting network
   inventory that is application- and technology-agnostic.  The base
   data model can be augmented to describe application- and technology-
   specific information.  Please note that the usage of term "network
   inventory", in the context of this I-D, is to indicate that it is
   describing "network-wide" scope inventory information.

   Network Inventory is a collection of data for network devices and
   their components managed by a specific management system.

   Network inventory is a fundamental functional block in the overall
   network management which was specified many years ago.  Network
   inventory management is a critical part for ensuring that the network
   remains healthy (e.g., auditing to identify faulty elements), well-
   planned (e.g., identify assets to upgrade or to decommission), and
   maintained appropriately to meet the performance objectives.  Also,
   network inventory management allows operators to keep track of which
   devices are deployed in their networks, including relevant embedded
   software and hardware versions.

   Exposing standard interfaces to retrieve network elements
   capabilities as maintained in an inventory are key enablers for many
   applications.  For example, [I-D.ietf-teas-actn-poi-applicability]
   identifies a gap about the lack of YANG data models that could be
   used at Abstraction and Control of TE Networks (ACTN) Multi-Domain
   Service Coordinator-Provisioning Network Controller Interface (MPI)
   level to report whole or partial network hardware inventory
   information available at domain controller level towards upper layer
   systems (e.g., Multi-Domain Service Coordinator (MDSC) or Operations
   Support Systems (OSS) layers).

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   It is key for operators to coordinate with the industry towards the
   use of a standard YANG data model for Network Inventory data instead
   of using vendors proprietary APIs.

   [RFC8348] defines a YANG data model for the management of the
   hardware on a single server and therefore it is more applicable to
   the domain controller towards the network elements rather than at the
   northbound interface of a network controller (e.g., toward an
   application or another hierarchical network controller).  However,
   the YANG data model defined in [RFC8348] has been used as a reference
   for defining the YANG network inventory data model presented in this
   document.

   Per the definition of [RFC8969], the YANG data model defined in
   [RFC8348] is a device model while the YANG data model defined in this
   document is a network model.

   This document defines one YANG module "ietf-network-inventory" in
   Section 5.

   This base data model is application- and technology-agnostic (that
   is, valid for IP/MPLS, optical, and microwave networks as well as
   optical local loops, access networks, core networks, data centers,
   etc.) and can be augmented to include required application- and
   technology-specific inventory details together with specific hardware
   or software component's attributes.

   The YANG data model defined in the document is scoped to cover the
   common use cases for Inventory but at network-wide level, covering
   both hardware and base software information.

   The YANG data model defined in this document conforms to the Network
   Management Datastore Architecture [RFC8342].

1.1.  Editorial Note (To be removed by RFC Editor)

      Note to the RFC Editor: This section is to be removed prior to
      publication.

   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.

   Please apply the following replacements:

   *  XXXX --> the assigned RFC number for this I-D

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2.  Terminology and Notations

2.1.  Requirements Notations

   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.

2.2.  Terminology

   The following terms are defined in [RFC7950] and are not redefined
   here:

   *  server

   *  augment

   *  data model

   *  data node

   The following terms are defined in [RFC6241] and are not redefined
   here:

   *  configuration data

   *  state data

   The following terms are defined in [RFC8342] and are not redefined
   here:

   *  applied configuration

   The following terms are defined in the description statements of the
   corresponding YANG identities, defined in [IANA_HW_YANG], and are not
   redefined here:

   *  backplane

   *  battery

   *  cpu

   *  fan

   *  module

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   *  power supply

   *  sensor

   *  stack

   *  storage device

   Chassis:  A field replaceable equipment with a particular structural
      format and dimensions.  A chassis can, but does not need to,
      include spaces (called slots) to take cards.

      Elsewhere, a chassis can be called shelf, sub-rack, stand-alone
      unit, etc.

   Port:  A component where networking traffic can be received and/or
      transmitted, e.g., by attaching networking cables.

      In case of pluggable ports, the port may be empty when no
      pluggable module is plugged in.

   Also, the document makes use of the following terms:

   Network Inventory:  A collection of data for network elements and
      their components with network-wide scope, managed by a specific
      management system.

   Physical Network Element:  An implementation or application specific
      group of components (e.g., hardware components).

   Network Element:  The generalization of the physical network element
      definition.

   Hardware Component:  The generalization of the hardware components
      defined in [IANA_HW_YANG] (e.g., backplane, battery, container,
      cpu, chassis, fan, module, port, power supply, sensor, stack, and
      storage device components).

      The list of hardware components can be extended in future versions
      of [IANA_ENTITY_MIB] (and, consequently, of ([IANA_HW_YANG]).

   Component:  The generalization of the hardware component definition
      to include other inventory objects which can be managed, from an
      inventory perspective, like hardware components.

   Card:  A pluggable equipment with a particular structural format and

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      dimensions which can be inserted into one or more slots (or sub-
      slots).  A card can have spaces (called sub-slots) to take other
      cards.

      Elsewhere, a card can be called board, module, circuit pack, etc..

   Slot:  A space in a chassis that can be equipped with one card, which
      may be chosen from a limited range of types of cards.  A slot can
      be subdivided into smaller spaces (called sub-slots).

   Container:  A hardware component class that is capable of containing
      one or more removable physical entities (e.g., a slot in a chassis
      is containing a board).

2.3.  Tree Diagrams

   The meanings of the symbols in the YANG tree diagrams are defined in
   [RFC8340].

2.4.  YANG Prefixes

   Table 1 list the prefixes of the modules that are used in this
   document.

       +========+========================+========================+
       | Prefix | YANG Module            | Reference              |
       +========+========================+========================+
       | inet   | ietf-inet-types        | Section 4 of [RFC6991] |
       +--------+------------------------+------------------------+
       | yang   | ietf-yang-types        | Section 3 of [RFC6991] |
       +--------+------------------------+------------------------+
       | ianahw | iana-hardware          | [IANA_HW_YANG]         |
       +--------+------------------------+------------------------+
       | nwi    | ietf-network-inventory | RFC XXXX               |
       +--------+------------------------+------------------------+

             Table 1: Prefixes and corresponding YANG modules

3.  YANG Data Model for Network Inventory Overview

   The base network inventory model, defined in this document, provides
   a list of network elements and of network element components:

   The network-inventory top level container has been defined to support
   reporting other types of network inventory objects, besides the
   network elements and network element components.

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   These additional types of network inventory objects can be defined,
   together with the associated YANG data model and the rationale for
   managing them as part of the network inventory, in other documents
   providing application- and technology-specific companion augmentation
   data models, such as [I-D.ietf-ivy-network-inventory-location].

   The network element definition is generalized to support physical
   network elements and other types of components' groups that can be
   managed as physical network elements from an inventory perspective.

   Physical network elements are usually devices such as hosts,
   gateways, terminal servers, and the like, which have management
   agents responsible for performing the network management functions
   requested by the network management stations ([RFC1157]).

   The "ne-type" is defined as a YANG identity to describe the type of
   the network element.  This document defines only the "physical-
   network-element" identity.

   Other types of network elements can be defined in other documents,
   together with the associated YANG identity and the rationale for
   managing them as network elements from an inventory perspective.

   The component definition is also generalized to support any types of
   component inventory objects that can be managed as hardware
   components from an inventory perspective.

   The data model for components defined in this document uses a list of
   components within each network element.

   Different types of components can be distinguished by the class of
   component.  The component "class" is defined as a union between the
   hardware class identity, defined in "iana-hardware", and the "non-
   hardware" identity, defined in this document.

   Other types of components can be defined in other documents, together
   with the associated YANG identity and the rationale for managing them
   as components from an inventory perspective.

   The identity definition of additional types of "ne-type" and "non-
   hardware" identity of component are outside the scope of this
   document and could be defined in application- and technology-specific
   companion augmentation data models, such as
   [I-D.ietf-ivy-network-inventory-software].

   In [RFC8348], rack, chassis, slot, sub-slot, board and port are
   defined as components of network elements with generic attributes.

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   While [RFC8348] is used to manage the hardware of a single server
   (e.g., a network element), the Network Inventory YANG data model is
   used to retrieve the base inventory information that a controller
   discovers from all the network elements with network-wide scope under
   its control.

   However, the YANG data model defined in [RFC8348] has been used as a
   reference for defining the YANG network inventory data model.  This
   approach can simplify the implementation of this inventory model when
   the controller uses the YANG data model defined in [RFC8348] to
   retrieve the hardware from the network elements under its control.

3.1.  Common attributes for inventory object

   For all the inventory objects, there are some common attributes, such
   as:

   uuid:  The Universally Unique Identifier (UUID) of the inventory
      object, assigned by the server.  Such identifiers are widely
      implemented with systems and guaranteed to be globally unique.

   name:  A human-readable label information of the inventory object,
      which could be assigned by the server.  It could also be present
      on a Graphical User Interface (GUI).

   alias:  A human-readable label information of the inventory object,
      provided by a network operator.  It could also be present on a GUI
      instead as well as the name.

   description:  A human-readable description of the inventory object,
      provided by a network operator or by the server.  The description
      provides more detailed information to prompt users when performing
      maintenance operations etc.

3.1.1.  Common attributes for network elements and components

   To be consistent with the component definition, some of the
   attributes defined in [RFC8348] for components are reused for network
   elements, such as:

   mfg-name:  The name of the manufacturer of the entity (component or
      network element).

   product-name:  The vendor-specific and human-interpretable string
      describing the entity (component or network element) type.

      It is expected that vendors assign unique product names to
      different entities within the scope of the vendor.

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   Other software-related attributes are defined in Section 3.3.2 and
   applicable to network elements and components.

3.2.  Network Element

   In addition to the common attributes defined for network elements and
   components in Section 3.1, the following attributes are defined for
   the network elements:

   ne-id:  The identifier that uniquely identifies the NE within the
      network, assigned by the server since the network elements cannot
      guaranteed that their local identifier is unique within the
      network.

      The ne-id should be assigned such that the same network element
      will always be identified through the same identifier, even if the
      network elements get disconnected from the network controller.
      Mechanisms to ensure this (e.g., checking the mfg-name, product-
      name, management IP address, physical location) are implementation
      specific and outside the scope of standardization.

   ne-type:  The type of network element (e.g., physical network
      element).  See Section 3 for the definition of NE types.

   product-rev:  A vendor-specific product revision string for the
      network-element.

3.3.  Components

   The YANG data model for network inventory mainly follows the same
   approach of [RFC8348] and reports the network hardware inventory as a
   list of components with different types (e.g., chassis, module, and
   port).

   In addition to the common attributes defined for network elements and
   components in Section 3.1, the following attributes are defined for
   the network elements:

   component-id:  The identifier that uniquely identifies the component
      within the NE.  It can be assigned by the NE or by the server.

   class:  The type of component (e.g., chassis, module, port).  See
      Section 3 for the definition of component types.

   hardware-rev:  The vendor-specific hardware revision string for the
      component.

      The preferred value is the hardware revision identifier actually

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      printed on the component itself (if present).

   mfg-date:  The date of manufacturing of the component.

   part-number:  The vendor-specific part number of the component type.

      It is expected that vendors assign unique part numbers to
      different component types within the scope of the vendor.

   serial-number:  The vendor-specific serial number of the the
      component instance.

      It is expected that vendors assign unique serial numbers to
      different component instances at least within the scope of the
      part-number.

   asset-id:  An asset tracking identifier for the component, provided
      by a network operator.

   is-fru:  Indicates whether or not a component is considered a 'field-
      replaceable unit' by the vendor.

   For state data like "admin-state", "oper-state", and so on, this
   document considers that they are related to device hardware
   management, not network inventory.  Therefore, they are outside of
   the scope of this document.  Same for the sensor-data, they should be
   defined in some other performance monitoring data models instead of
   the inventory data model.

3.3.1.  Hardware Components

   Based on TMF classification in [TMF_SD2-20], hardware components can
   be divided into two groups, holder group and equipment group.  The
   holder group contains rack, chassis, slot, sub-slot while the
   equipment group contains network-element, board and port.

   Figure 1 describes the relationship between typical inventory objects
   in a physical network element.

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                               +-----------------+
                               | network element |
                               +-----------------+
                                       ||
                                       ||
                                       ||
                                       ||1:M
                                       ||
                                       ||
                                       ||
                                       \/
                                 +-------------+
                                 |   chassis/  |---+
                                 | sub-chassis |<--|
                                 +-------------+
                                       ||
                        ______1:N______||_____1:M_______
                        ||------------------ ---------||
                        \/                            \/
                 +--------------+               +-----------+
             +---|     slot     |               |   board   |
             |-->|  /sub-slot   |               |           |
                 +--------------+               +-----------+
                                                      ||
                                                      ||1:N
                                                      \/
                                                +-----------+
                                                |    port   |
                                                +-----------+

        Figure 1: Relationship between typical inventory objects in
                         physical network elements

   The "iana-hardware" module [IANA_HW_YANG] defines YANG identities for
   the hardware component types in the IANA-maintained "IANA-ENTITY-MIB"
   registry.

   Some of the definitions taken from [RFC8348] are based on the ENTITY-
   MIB [RFC6933].

   Additional attributes of specific hardware, such as CPU, storage,
   port, or power supply are defined in the hardware extension.

3.3.2.  Software Components

   This document defines a "software-rev" list for NEs and components,
   which provide basic software attributes for network elements and
   components.

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   The scope of the list is to provide information about the software
   modules configured to be active on the related entity (network
   element or component).

   The model supports scenarios where multiple software modules can be
   configured to be active on the entity.  For example, on a network
   element an Operating System and an Application software modules can
   be configured to be active; in the same way, on a component like a
   circuit pack a boot-loader, a firmware and one or more FPGA software
   modules can be configured to be active.

   For each software module, configured to be active, the name and
   version information is provided.

   The management of inactive/standby software modules and of the
   software upgrade or downgrade life-cycle are outside the scope of the
   base inventory model and can be addressed in other models which
   augment the base inventory model such as the model under definition
   in [I-D.ietf-ivy-network-inventory-software].

   The software and hardware components share the same attributes of the
   component and have similar replaceable requirements.  Generally, the
   device also has other software data, for example, one or more
   software patch information.

   The software components of other classes, such as platform software,
   BIOS, bootloader, and software patch information, are outside the
   scope of this document and defined other documents such as
   [I-D.ietf-ivy-network-inventory-software].

3.4.  Changes Since RFC 8348

   This document re-defines some attributes listed in [RFC8348], based
   on some integration experience for network inventory data.

3.4.1.  Part Number

   According to the description in [RFC8348], the attribute named
   "model-name" under the component, is preferred to have a customer-
   visible part number value.  "Model-name" is not straightforward to
   understand and we suggest to rename it as "part-number" directly.

3.4.2.  Component identifiers

   There are some use cases where the name of the components are
   assigned and changed by the operator.  In these cases, the assigned
   names are also not guaranteed to be always unique.

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   In order to support these use cases, this model is not aligned with
   [RFC8348] in defining the component name as the key for the component
   list.

   Instead the name is defined as an optional attribute and the
   component-id is defined as the key for the component list (in
   alignment with the approach followed for the network-element list).

4.  Network Inventory Tree Diagram

   Figure 2 below shows the tree diagram of the YANG data model defined
   in module "ietf-network-inventory" (Section 5).

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   module: ietf-network-inventory
     +--ro network-inventory
        +--ro network-elements
           +--ro network-element* [ne-id]
              +--ro ne-id           string
              +--ro ne-type?        identityref
              +--ro uuid?           yang:uuid
              +--ro name?           string
              +--ro alias?          string
              +--ro description?    string
              +--ro software-rev* [name]
              |  +--ro name        string
              |  +--ro revision?   string
              |  +--ro patch* [revision]
              |     +--ro revision    string
              +--ro mfg-name?       string
              +--ro product-name?   string
              +--ro product-rev?    string
              +--ro components
                 +--ro component* [component-id]
                    +--ro component-id      string
                    +--ro class             union
                    +--ro uuid?             yang:uuid
                    +--ro name?             string
                    +--ro alias?            string
                    +--ro description?      string
                    +--ro software-rev* [name]
                    |  +--ro name        string
                    |  +--ro revision?   string
                    |  +--ro patch* [revision]
                    |     +--ro revision    string
                    +--ro mfg-name?         string
                    +--ro product-name?     string
                    +--ro hardware-rev?     string
                    +--ro mfg-date?         yang:date-and-time
                    +--ro part-number?      string
                    +--ro serial-number?    string
                    +--ro asset-id?         string
                    +--ro is-fru?           boolean
                    +--ro uri*              inet:uri
                    +--ro parent-rel-pos?   int32
                    +--ro parent*
                    |       -> ../../component/component-id
                    +--ro is-main?          boolean

                  Figure 2: Network inventory tree diagram

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5.  YANG Data Model for Network Inventory

   <CODE BEGINS> file "ietf-network-inventory@2025-10-07.yang"
   module ietf-network-inventory {
     yang-version 1.1;
     namespace "urn:ietf:params:xml:ns:yang:ietf-network-inventory";
     prefix nwi;

     import iana-hardware {
       prefix ianahw;
       reference
         "https://www.iana.org/assignments/yang-parameters";
     }
     import ietf-yang-types {
       prefix yang;
       reference
         "RFC 6991: Common YANG Data Types";
     }
     import ietf-inet-types {
       prefix inet;
       reference
         "RFC 6991: Common YANG Data Types";
     }

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

        Editor:   Chaode Yu
                  <yuchaode@huawei.com>

        Editor:   Sergio Belotti
                  <sergio.belotti@nokia.com>

        Editor:   Jean-Francois Bouquier
                  <jeff.bouquier@vodafone.com>

        Editor:   Fabio Peruzzini
                  <fabio.peruzzini@telecomitalia.it>

        Editor:   Phil Bedard
                  <phbedard@cisco.com>";
     description
       "This module defines a base model for retrieving network
        inventory.

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        The model fully conforms to the Network Management
        Datastore Architecture (NMDA).

        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; see
        the RFC itself for full legal notices.

        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 (RFC 2119) (RFC 8174) when, and only when,
        they appear in all capitals, as shown here.";

     // RFC Ed.: update the date below with the date of RFC publication
     // and remove this note.

     revision 2025-10-09 {
       description
         "Initial version";
       reference
         "RFC XXXX: A YANG Data Model for Network Inventory.";
     }

     /*
      * Identities
      */

     identity non-hardware-component-class {
       description
         "Base identity for non hardware components (e.g., software
          components) in a managed device.";
     }

     identity ne-type {
       description
         "Base identity for Network Element (NE) types.";
     }

     identity ne-physical {

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       base nwi:ne-type;
       description
         "A physical network element (NE). ";
     }

     /*
      * Types
      */

     typedef ne-ref {
       type leafref {
         path "/nwi:network-inventory/nwi:network-elements"
            + "/nwi:network-element/nwi:ne-id";
       }
       description
         "This type is intended to be used by data models that need to
          reference Network Element.";
     }

     /*
      * Groupings
      */

     grouping port-ref {
       description
         "This grouping is intended to be used by data models that need
          to reference a port component within a Network Element.";
       leaf ne-ref {
         type nwi:ne-ref;
         description
           "The reference to the Network Element which contains the
            port to be referenced.";
       }
       leaf port-ref {
         type leafref {
           path "/nwi:network-inventory/nwi:network-elements/"
              + "nwi:network-element[nwi:ne-id=current()/../ne-ref]"
              + "/nwi:components/nwi:component/nwi:component-id";
         }
         must "derived-from-or-self (/nwi:network-inventory/
               nwi:network-elements/nwi:network-element
               [nwi:ne-id=../ne-ref]/nwi:components/nwi:component
               [nwi:component-id=current()]/nwi:class, 'ianahw:port')";
         description
           "The reference to the port component.";
       }
     }

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     grouping basic-common-entity-attributes {
       description
         "The set of basic attributes which are common to all the
          entities (e.g., component, network elements, location, passive
          entities) defined in this module and in other inventory
          modules.";
       leaf uuid {
         type yang:uuid;
         description
           "The Universally Unique Identifier of the entity
            (e.g., component).";
       }
       leaf name {
         type string;
         description
           "The name of the  entity (e.g., component), as specified by
            a network operator, that provides a non-volatile 'handle'
            for the entity and that can be modified anytime during the
            entity lifetime.

            If no configured value exists, the server MAY set the value
            of this node to a locally unique value in the operational
            state.";
       }
       leaf alias {
         type string;
         description
           "The alias name of the entity (e.g., component). This alias
            name can be specified by a network operator.";
       }
       leaf description {
         type string;
         description
           "The textual description of the entity (e.g., component).";
       }
     }

     grouping ne-component-common-entity-attributes {
       description
         "The set of attributes which are common to all the entities
          (e.g., component, network elements) defined in this module.";
       uses basic-common-entity-attributes;
       list software-rev {
         key "name";
         description
           "The list of the software modules configured to be active
            within the entity (e.g., component).";
         leaf name {

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           type string;
           description
             "The vendor-specific name of the software module.";
         }
         leaf revision {
           type string;
           description
             "The vendor-specific revision string of the software
              module when not implicitly defined as part of the name of
              the software module.";
         }
         list patch {
           key "revision";
           description
             "The list of software patches configured to be active for
              the software module.";
           leaf revision {
             type string;
             description
               "The vendor-specific revision string of the software
                patch when not implicitly defined as part of the name or
                revision of the software module.";
           }
         }
       }
       leaf mfg-name {
         type string;
         description
           "The name of the manufacturer of this entity
            (e.g., component).";
       }
       leaf product-name {
         type string;
         description
           "The vendor-specific and human-interpretable string
            describing the entity (e.g., component) type. It is expected
            that vendors assign unique product names to different entity
            (e.g., component) types within the scope of the vendor.";
       }
     }

     grouping component-attributes {
       description
         "The set of common attributes of a component.

          This grouping is intended also to be re-used by data models
          that need to report the common attributes of a component.";
       leaf component-id {

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         type string;
         description
           "An identifier that uniquely identifies the component
            in a node.";
       }
       leaf class {
         type union {
           type identityref {
             base ianahw:hardware-class;
           }
           type identityref {
             base non-hardware-component-class;
           }
         }
         mandatory true;
         description
           "The type of the component.";
       }
       uses ne-component-common-entity-attributes {
         refine "software-rev" {
           reference
             "RFC 6933: Entity MIB (Version 4) -
                        entPhysicalSoftwareRev";
         }
         refine "mfg-name" {
           description
             "The name of the manufacturer of this physical
              component.
              The preferred value is the manufacturer name
              string actually printed on the component itself
              (if present).

              Note that comparisons between instances of the
              'model-name', 'software-rev', and 'serial-number' nodes
              are only meaningful amongst components with the same value
              of 'mfg-name'.

              If the manufacturer name string associated with
              the physical component is unknown to the server,
              then this node is not instantiated.";
           reference
             "RFC 6933: Entity MIB (Version 4) -
                        entPhysicalMfgName";
         }
       }
       leaf hardware-rev {
         type string;
         description

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           "The vendor-specific hardware revision string for the
            component.

            The preferred value is the hardware revision identifier
            actually printed on the component itself (if present).";
         reference
           "RFC 6933: Entity MIB (Version 4) - entPhysicalHardwareRev";
       }
       leaf mfg-date {
         type yang:date-and-time;
         description
           "The date of manufacturing of the component.";
         reference
           "RFC 6933: Entity MIB (Version 4) - entPhysicalMfgDate";
       }
       leaf part-number {
         type string;
         description
           "The vendor-specific part number of the component
            type. It is expected that vendors assign unique part
            numbers to different component types within the
            scope of the vendor.";
       }
       leaf serial-number {
         type string;
         description
           "The vendor-specific serial number of the the entity
            (e.g., component) instance. It is expected that vendors
            assign unique serial numbers to different network element
            instances within the scope of the product name.";
       }
       leaf asset-id {
         type string;
         description
           "This node is an asset tracking identifier for the component,
            as specified by a network operator.

            A server implementation MAY map this leaf to the
            entPhysicalAssetID MIB object.  Such an
            implementation needs to use some mechanism to handle
            the differences in size and characters allowed
            between this leaf and entPhysicalAssetID.

            The definition of such a mechanism is outside the
            scope of this document.";
         reference
           "RFC 6933: Entity MIB (Version 4) -
                      entPhysicalAssetID";

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       }
       leaf is-fru {
         type boolean;
         description
           "This node indicates whether or not this component is
            considered a 'field-replaceable unit' by the vendor.
            If this node contains the value 'true', then this
            component identifies a field-replaceable unit.
            For all components that are permanently contained
            within a field-replaceable unit, the value 'false'
            should be returned for this node.";
         reference
           "RFC 6933: Entity MIB (Version 4) -
                      entPhysicalIsFRU";
       }
       leaf-list uri {
         type inet:uri;
         description
           "This node contains identification information about
            the component.";
         reference
           "RFC 6933: Entity MIB (Version 4) - entPhysicalUris";
       }
     }

     /*
      * Data Nodes
      */

     container network-inventory {
       config false;
       description
         "Top-level container for network inventory.";
       container network-elements {
         description
           "The top-level container for the list of network elements
            within the network.";
         list network-element {
           key "ne-id";
           description
             "The list of network elements within the network.";
           leaf ne-id {
             type string;
             description
               "An identifier that uniquely identifies the NE in
                a network.";
           }
           leaf ne-type {

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             type identityref {
               base nwi:ne-type;
             }
             default "nwi:ne-physical";
             description
               "The NE type.";
           }
           uses ne-component-common-entity-attributes;
           leaf product-rev {
             type string;
             description
               "The vendor-specific product revision string for the
                network-element.";
           }
           container components {
             description
               "The top-level container for the list of components
                within a network element.";
             list component {
               key "component-id";
               description
                 "The list of components within a network element.";
               uses component-attributes;
               leaf parent-rel-pos {
                 when 'count(../parent) < 2' {
                   description
                     "This data node is applicable only when this
                      component is contained in the network-element or
                      in only one parent component.";
                 }
                 type int32 {
                   range "0 .. 2147483647";
                 }
                 description
                   "The relative position with respect to the parent
                    component among all the sibling components.";
                 reference
                   "RFC 6933: Entity MIB (Version 4) -
                              entPhysicalParentRelPos";
               }
               leaf-list parent {
                 type leafref {
                   path "../../component/component-id";
                   require-instance false;
                 }
                 description
                   "The identifiers of all the components that
                    physically contain this component.

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                    If this list is empty, this component is not
                    contained in any other component but it is contained
                    in the network-element.";
                 reference
                   "RFC 6933: Entity MIB (Version 4) -
                              entPhysicalContainedIn";
               }
               leaf is-main {
                 when "derived-from-or-self(../nwi:class, "
                    + "'ianahw:chassis')";
                 type boolean;
                 description
                   "This node indicates whether the chassis is taking or
                    not the 'main' role.

                    This node is applicable only to scenarios where
                    there are chassis components which can take the
                    'main' role (e.g., multi-chassis network elements),
                    otherwise it is omitted.";
               }
             }
           }
         }
       }
     }
   }
   <CODE ENDS>

                  Figure 3: Network inventory YANG module

6.  Operational Considerations

   The network inventory YANG data model defined in the document is
   intended to report the actual inventory data that a network
   controller knows of the network elements and components actually
   installed within the network.  Therefore, this data model provides a
   read-only perspective of the network inventory information.

   As outlined in Section 1, per the definition of [RFC8969], the
   network inventory model is a network model.

   This information can be provided by a network controller to an higher
   level hierarchical network controller, to an Inventory OSS or to any
   other type of application which needs to discover the network
   inventory information.

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   For example, in the context of ACTN, the network inventory YANG data
   model can be used at the MPI interfaces, as defined in [RFC8453], or
   on an interface, not defined in [RFC8453] between the MDSC and the
   Inventory OSS.

   The information in the model is populated by controller by reading it
   from the devices using the device model supported by the devices.
   This model does not constraint the device models used on the device:
   the YANG data model defined in [RFC8348] is an option but other
   options (e.g., vendor specific interfaces or YANG data models) are
   also allowed.  In case some information is not provided by the
   device, the network controller SHALL omit this information unless
   this information is known by other sources of information (e.g.,
   through local configuration within the network controller).

   In case of hierarchical controllers, a hierarchical network
   controller can also collect the network inventory information from
   its lower level network controllers using this YANG data model (or
   other mechanisms which are outside the scope of this document) and
   report the combined network inventory information to an an higher
   level network controller, to an Inventory OSS or to any other type of
   application which needs to discover the network inventory
   information.

7.  Security Considerations

   This section is modeled after the template described in Section 3.7
   of [I-D.ietf-netmod-rfc8407bis].

   The "ietf-network-inventory" YANG module defines a data model that is
   designed to be accessed via YANG-based management protocols, such as
   NETCONF [RFC6241] and RESTCONF [RFC8040].  These YANG-based
   management protocols (1) have to use a secure transport layer (e.g.,
   SSH [RFC4252], TLS [RFC8446], and QUIC [RFC9000]) and (2) have to use
   mutual authentication.

   The Network 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.

   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:

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   Specifically, the following subtrees and data nodes have particular
   sensitivities/vulnerabilities:

   *  "/nwi:network-elements"

      This subtree reports the inventory information for all the network
      elements and their hardware components deployed within the network
      as well as of the software modules being active on these network
      elements and components.  Unauthorized access to this subtree can
      disclose this information.  A malicious attacker can use this
      information to perform targeted attacks to network elements,
      hardware components or software modules with known
      vulnerabilities.

   Modules that use the groupings that are defined in this document
   should identify the corresponding security considerations.  For
   example, reusing the 'component-attributes' grouping may expose
   sensitive information.

8.  IANA Considerations

   IANA is requested to register the following URI in the "ns" registry
   within the "IETF XML Registry" group [RFC3688]:

         URI: urn:ietf:params:xml:ns:ietf-network-inventory
         Registrant Contact: The IESG
         XML: N/A; the requested URI is an XML namespace.

   IANA is requested to register the following YANG module in the "YANG
   Module Names" registry [RFC6020] within the "YANG Parameters"
   registry group.

        name:         ietf-network-inventory
        namespace:    urn:ietf:params:xml:ns:yang:ietf-network-inventory
        prefix:       nwi
        reference:    RFC XXXX

9.  References

9.1.  Normative References

   [IANA_ENTITY_MIB]
              IANA, "IANA-ENTITY-MIB", n.d.,
              <https://www.iana.org/assignments/ianaentity-mib/
              ianaentity-mib.xhtml>.

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   [IANA_HW_YANG]
              IANA, "iana-hardware YANG Module", n.d.,
              <https://www.iana.org/assignments/iana-hardware/iana-
              hardware.xhtml>.

   [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/rfc/rfc2119>.

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

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

   [RFC6933]  Bierman, A., Romascanu, D., Quittek, J., and M.
              Chandramouli, "Entity MIB (Version 4)", RFC 6933,
              DOI 10.17487/RFC6933, May 2013,
              <https://www.rfc-editor.org/rfc/rfc6933>.

   [RFC6991]  Schoenwaelder, J., Ed., "Common YANG Data Types",
              RFC 6991, DOI 10.17487/RFC6991, July 2013,
              <https://www.rfc-editor.org/rfc/rfc6991>.

   [RFC7950]  Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
              RFC 7950, DOI 10.17487/RFC7950, August 2016,
              <https://www.rfc-editor.org/rfc/rfc7950>.

   [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/rfc/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/rfc/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/rfc/rfc8342>.

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   [RFC8348]  Bierman, A., Bjorklund, M., Dong, J., and D. Romascanu, "A
              YANG Data Model for Hardware Management", RFC 8348,
              DOI 10.17487/RFC8348, March 2018,
              <https://www.rfc-editor.org/rfc/rfc8348>.

   [TMF_SD2-20]
              TM Forum, "SD2-20_Equipment Model", TMF MTOSI 4.0, Network
              Resource Fulfilment (NRF), SD2-20 , May 2008,
              <https://www.tmforum.org/resources/suite/mtosi-4-0/>.

9.2.  Informative References

   [I-D.ietf-ivy-network-inventory-location]
              Wu, B., Belotti, S., Bouquier, J., Peruzzini, F., and P.
              Bedard, "A YANG Data Model for Network Inventory
              Location", Work in Progress, Internet-Draft, draft-ietf-
              ivy-network-inventory-location-03, 7 July 2025,
              <https://datatracker.ietf.org/doc/html/draft-ietf-ivy-
              network-inventory-location-03>.

   [I-D.ietf-ivy-network-inventory-software]
              Wu, B., Zhou, C., Wu, Q., and M. Boucadair, "A YANG
              Network Data Model of Network Inventory Software
              Extensions", Work in Progress, Internet-Draft, draft-ietf-
              ivy-network-inventory-software-01, 10 June 2025,
              <https://datatracker.ietf.org/doc/html/draft-ietf-ivy-
              network-inventory-software-01>.

   [I-D.ietf-netmod-rfc8407bis]
              Bierman, A., Boucadair, M., and Q. Wu, "Guidelines for
              Authors and Reviewers of Documents Containing YANG Data
              Models", Work in Progress, Internet-Draft, draft-ietf-
              netmod-rfc8407bis-28, 5 June 2025,
              <https://datatracker.ietf.org/doc/html/draft-ietf-netmod-
              rfc8407bis-28>.

   [I-D.ietf-teas-actn-poi-applicability]
              Peruzzini, F., Bouquier, J., Busi, I., King, D., and D.
              Ceccarelli, "Applicability of Abstraction and Control of
              Traffic Engineered Networks (ACTN) to Packet Optical
              Integration (POI)", Work in Progress, Internet-Draft,
              draft-ietf-teas-actn-poi-applicability-16, 9 October 2025,
              <https://datatracker.ietf.org/doc/html/draft-ietf-teas-
              actn-poi-applicability-16>.

   [I-D.ygb-ivy-passive-network-inventory]
              Yu, C., Guo, A., Busi, I., Boroon, M., Belotti, S., van
              caenegem, T., S., S. 1., B., S., Davis, N., Tilocca, M.,

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              Peters, B., Yoon, B. Y., LIUYUCONG, Zhao, Y., and A.
              Sakalabhaktula, "A YANG Data Model for Passive Network
              Inventory", Work in Progress, Internet-Draft, draft-ygb-
              ivy-passive-network-inventory-02, 7 July 2025,
              <https://datatracker.ietf.org/doc/html/draft-ygb-ivy-
              passive-network-inventory-02>.

   [RFC1157]  Case, J., Fedor, M., Schoffstall, M., and J. Davin,
              "Simple Network Management Protocol (SNMP)", RFC 1157,
              DOI 10.17487/RFC1157, May 1990,
              <https://www.rfc-editor.org/rfc/rfc1157>.

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

   [RFC4252]  Ylonen, T. and C. Lonvick, Ed., "The Secure Shell (SSH)
              Authentication Protocol", RFC 4252, DOI 10.17487/RFC4252,
              January 2006, <https://www.rfc-editor.org/rfc/rfc4252>.

   [RFC7951]  Lhotka, L., "JSON Encoding of Data Modeled with YANG",
              RFC 7951, DOI 10.17487/RFC7951, August 2016,
              <https://www.rfc-editor.org/rfc/rfc7951>.

   [RFC8040]  Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
              Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
              <https://www.rfc-editor.org/rfc/rfc8040>.

   [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/rfc/rfc8340>.

   [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/rfc/rfc8446>.

   [RFC8453]  Ceccarelli, D., Ed. and Y. Lee, Ed., "Framework for
              Abstraction and Control of TE Networks (ACTN)", RFC 8453,
              DOI 10.17487/RFC8453, August 2018,
              <https://www.rfc-editor.org/rfc/rfc8453>.

   [RFC8969]  Wu, Q., Ed., Boucadair, M., Ed., Lopez, D., Xie, C., and
              L. Geng, "A Framework for Automating Service and Network
              Management with YANG", RFC 8969, DOI 10.17487/RFC8969,
              January 2021, <https://www.rfc-editor.org/rfc/rfc8969>.

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   [RFC9000]  Iyengar, J., Ed. and M. Thomson, Ed., "QUIC: A UDP-Based
              Multiplexed and Secure Transport", RFC 9000,
              DOI 10.17487/RFC9000, May 2021,
              <https://www.rfc-editor.org/rfc/rfc9000>.

Appendix A.  Comparison With Openconfig-platform Data Model

   Since more and more devices can be managed by domain controller
   through OpenConfig, to ensure that our inventory data model can cover
   these devices' inventory data, we have compared our inventory data
   model with the "openconfig-platform" model which is the data model
   used to manage inventory information in OpenConfig.

   Openconfig-platform data model is NE-level and uses a generic
   component concept to describe its inner devices and containers, which
   is similar to "ietf-hardware" model in [RFC8348].  Since we have also
   reused the component concept of [RFC8348] in our inventory data
   model, we can compare the component's attributes between "openconfig-
   platform" and our model directly , which is stated below:

   +========================+===================+======================+
   | Attributes in oc-      | Attributes in our | remark               |
   | platform               | model             |                      |
   +========================+===================+======================+
   | name                   | name              |                      |
   +------------------------+-------------------+----------------------+
   | type                   | class             |                      |
   +------------------------+-------------------+----------------------+
   | id                     | uuid              |                      |
   +------------------------+-------------------+----------------------+
   | location               | location          |                      |
   +------------------------+-------------------+----------------------+
   | description            | description       |                      |
   +------------------------+-------------------+----------------------+
   | mfg-name               | mfg-name          |                      |
   +------------------------+-------------------+----------------------+
   | mfg-date               | mfg-date          |                      |
   +------------------------+-------------------+----------------------+
   | hardware-version       | hardware-rev      |                      |
   +------------------------+-------------------+----------------------+
   | firmware-version       | firmware-rev      |                      |
   +------------------------+-------------------+----------------------+
   | software-version       | software-rev      |                      |
   +------------------------+-------------------+----------------------+
   | serial-no              | serial-num        |                      |
   +------------------------+-------------------+----------------------+
   | part-no                | part-number       |                      |
   +------------------------+-------------------+----------------------+

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   | clei-code              |                   | TBD                  |
   +------------------------+-------------------+----------------------+
   | removable              | is-fru            |                      |
   +------------------------+-------------------+----------------------+
   | oper-status            |                   | state data           |
   +------------------------+-------------------+----------------------+
   | empty                  | contained-child?  | If there is no       |
   |                        |                   | contained child, it  |
   |                        |                   | is empty.            |
   +------------------------+-------------------+----------------------+
   | parent                 | parent-references |                      |
   +------------------------+-------------------+----------------------+
   | redundant-role         |                   | TBD                  |
   +------------------------+-------------------+----------------------+
   | last-switchover-reason |                   | state data           |
   +------------------------+-------------------+----------------------+
   | last-switchover-time   |                   | state data           |
   +------------------------+-------------------+----------------------+
   | last-reboot-reason     |                   | state data           |
   +------------------------+-------------------+----------------------+
   | last-reboot-time       |                   | state data           |
   +------------------------+-------------------+----------------------+
   | switchover-ready       |                   | state data           |
   +------------------------+-------------------+----------------------+
   | temperature            |                   | performance data     |
   +------------------------+-------------------+----------------------+
   | memory                 |                   | performance data     |
   +------------------------+-------------------+----------------------+
   | allocated-power        |                   | TBD                  |
   +------------------------+-------------------+----------------------+
   | used-power             |                   | TBD                  |
   +------------------------+-------------------+----------------------+
   | pcie                   |                   | alarm data           |
   +------------------------+-------------------+----------------------+
   | properties             |                   | TBD                  |
   +------------------------+-------------------+----------------------+
   | subcomponents          |                   |                      |
   +------------------------+-------------------+----------------------+
   | chassis                |                   |                      |
   +------------------------+-------------------+----------------------+
   | port                   |                   |                      |
   +------------------------+-------------------+----------------------+
   | power-supply           |                   | TBD                  |
   +------------------------+-------------------+----------------------+
   | fan                    |                   | Fan is considered    |
   |                        |                   | as a specific        |
   |                        |                   | board.  And no need  |
   |                        |                   | to define as a       |

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   |                        |                   | single component     |
   +------------------------+-------------------+----------------------+
   | fabric                 |                   | TBD                  |
   +------------------------+-------------------+----------------------+
   | storage                |                   | For Optical and IP   |
   |                        |                   | technology, no need  |
   |                        |                   | to manage storage    |
   |                        |                   | on network element   |
   +------------------------+-------------------+----------------------+
   | cpu                    |                   | For Optical and IP   |
   |                        |                   | technology, no need  |
   |                        |                   | to manage CPU on     |
   |                        |                   | network element      |
   +------------------------+-------------------+----------------------+
   | integrated-circuit     |                   |                      |
   +------------------------+-------------------+----------------------+
   | backplane              |                   | Backplane is         |
   |                        |                   | considered as a      |
   |                        |                   | part of board.  And  |
   |                        |                   | no need to define    |
   |                        |                   | as a single          |
   |                        |                   | component            |
   +------------------------+-------------------+----------------------+
   | software-module        |                   | TBD                  |
   +------------------------+-------------------+----------------------+
   | controller-card        |                   | Controller card is   |
   |                        |                   | considered as a      |
   |                        |                   | specific functional  |
   |                        |                   | board.  And no need  |
   |                        |                   | to define as a       |
   |                        |                   | single component     |
   +------------------------+-------------------+----------------------+

       Table 2: Comparison between openconfig platform and inventory
                                data models

   As it mentioned in Section 3.3 that state data and performance data
   are out of scope of our data model, it is same for alarm data and it
   should be defined in some other alarm data models separately.  And
   for some component specific structures in "openconfig-platform", we
   consider some of them can be contained by our existing structure,
   such as fan, backplane, and controller-card, while some others do not
   need to be included in this network inventory model like storage and
   cpu.

   Mostly, our inventory data model can cover the attributes from
   OpenConfig.

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Appendix B.  Terminology of Container

   Within this document , with the term "container" we consider an
   hardware component class capable of containing one or more removable
   physical entities, e.g. a slot in a chassis is containing a board.

      +===============================+============================+
      | terminology of IVY base model | terminology in other model |
      +===============================+============================+
      | container                     | holder                     |
      +-------------------------------+----------------------------+

                       Table 3: terminology mapping

Appendix C.  Efficiency Issue

   During the integration with OSS in some operators, some efficiency/
   scalability concerns have been discovered when synchronizing network
   inventory data for big networks.  More discussions are needed to
   address these concerns.

   Considering that relational databases are widely used by traditional
   OSS systems and also by some network controllers, the inventory
   objects are most likely to be saved in different tables.  With the
   model defined in current draft, when doing a full synchronization,
   network controller needs to convert all inventory objects of each NE
   into component objects and combine them together into a single list,
   and then construct a response and send to OSS or MDSC.  The OSS or
   MDSC needs to classify the component list and divide them into
   different groups, in order to save them in different tables.  The
   combining-regrouping steps are impacting the network controller &
   OSS/MDSC processing, which may result in efficiency/scalability
   limitations in large scale networks.

   An alternative YANG model structure, which defines the inventory
   objects directly, instead of defining generic components, has also
   been analyzed.  However, also with this model, there still could be
   some scalability limitations when synchronizing full inventory
   resources in large scale of networks.  This scalability limitation is
   caused by the limited transmission capabilities of HTTP protocol.  We
   think that this scalability limitation should be solved at protocol
   level rather than data model level.

   The model proposed by this draft is designed to be as generic as
   possible so to cover future special types of inventory objects that
   could be used in other technologies, that have not been identified
   yet.  If the inventory objects were to be defined directly with fixed
   hierarchical relationships in YANG model, this new type of inventory

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   objects needs to be manually defined, which is not a backward
   compatible change and therefore is not an acceptable approach for
   implementation.  With a generic model, it is only needed to augment a
   new component class and extend some specific attributes for this new
   inventory component class, which is more flexible.  We consider that
   this generic data model, enabling a flexible and backward compatible
   approach for other technologies, represents the main scope of this
   draft.  Solution description to efficiency/scalability limitations
   mentioned above is considered as out-of-scope.

Appendix D.  Examples of ports

   This appendix provides some examples of port implementations and how
   they can be modelled using the "ietf-network-inventory" module
   defined in Section 5.

   Figure 4 shows an example of a single board which contains three type
   of ports:

   1.  An integrated port (non pluggable);

   2.  An empty port;

   3.  A pluggable port

             +-------------------+
             |               +---+
             |               | O |     1) Non-Pluggable Port
             |               | O |        (integrated)
             |               +---+
             |                   |
             |   +---------------+
             |   |                     2) Emply hole (port)
     Hole #1 |   |
             |   |
             |   |
             |   +---------------+
             |                   |
             |   +---------------+
             |   |  +---------------+
     Hole #2 |   |  |           | O |  3) Pluggable port
             |   |  |           | O |
             |   |  +---------------+
             |   +---------------+
             |                   |
             |     (SLOT # 10)   |
             +-------------------+

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         Figure 4: Example of a board with different types of ports

D.1.  JSON Examples

   This appendix contains an example of an instance data tree in JSON
   encoding [RFC7951], instantiating the "ietf-network-inventory" module
   to describe the three types of ports on a single board, as shown in
   Figure 4.

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

   {
     "ietf-network-inventory:network-inventory": {
       "network-elements": {
         "network-element" : [
           {
             "ne-id": "NE-1",
             "description": "Network element example with ports and \
                                                            breakouts.",
             "components": {
               "component": [
                 {
                   "component-id": "board-1",
                   "class": "iana-hardware:module",
                   "description": "Network element example with ports \
                                                         and breakouts."
                 },
                 {
                   "component-id": "port-1",
                   "class": "iana-hardware:port",
                   "description": "Example of an integrated (non-\
                                                      pluggable) port.",
                   "parent": [
                     "board-1"
                   ],
                   "parent-rel-pos": 1
                 },
                 {
                   "component-id": "port-2",
                   "class": "iana-hardware:port",
                   "description": "Example of an empty pluggable port.",
                   "parent": [
                     "board-1"
                   ],
                   "parent-rel-pos": 2
                 },
                 {
                   "component-id": "port-3",

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                   "class": "iana-hardware:port",
                   "description": "Example of a non empty pluggable \
                                                                 port.",
                   "parent": [
                     "board-1"
                   ],
                   "parent-rel-pos": 3
                 },
                 {
                   "component-id": "transceiver-module-3",
                   "class": "iana-hardware:module",
                   "description": "Example of a pluggable module \
                                      plugged within a pluggable port.",
                   "parent": [
                     "port-3"
                   ],
                   "is-fru": true
                 }
               ]
             }
           }
         ]
       }
     }
   }

Appendix E.  Example of multi-chassis network elements

   This appendix provides some examples of multi-chassis network
   elements and how they can be modelled using the "ietf-network-
   inventory" module defined in Section 5.

   Multi-chassis network elements are network elements composed by two
   or more chassis interconnected, in principle, with any topology.

   Stacked switches are an example of multi-chassis which consist of
   multiple standalone switches that are interconnected through
   dedicated stack ports and cables and managed as a single logical
   unit.  Stacked switch: - are connected using a daisy-chain or a ring
   topology - are managed using a single IP Address - synchronized
   software-upgrade - use Priority/MAC-Addr(s) decide Master/Members
   selection and communication.

   Figure 5 and Figure 6 describe two examples of stacked switch with
   three stacked switches (pizza boxes) connected in a daisy-chain or
   ring topology.

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       +--------------------------------------+
       |                                +---+ |
       |                                | 1 | |
       |        Chassis 1               +---+ |
       |                                +---+ |
       |                                | 2 |<----+
       |                                +---+ |   |
       +--------------------------------------+   |
                                                  |
                                                  |
       +--------------------------------------+   |
       |                                +---+ |   |
       |                                | 1 |<----+
       |        Chassis 2               +---+ |
       |                                +---+ |
       |                                | 2 |<----+
       |                                +---+ |   |
       +--------------------------------------+   |
                                                  |
                                                  |
       +--------------------------------------+   |
       |                                +---+ |   |
       |                                | 1 |<----+
       |        Chassis 3               +---+ |
       |                                +---+ |
       |                                | 2 | |
       |                                +---+ |
       +--------------------------------------+

      Figure 5: Example of a stacked switch in a daisy chain topology

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       +--------------------------------------+
       |                                +---+ |
       |                                | 1 |<---------+
       |        Chassis 1               +---+ |        |
       |                                +---+ |        |
       |                                | 2 |<----+    |
       |                                +---+ |   |    |
       +--------------------------------------+   |    |
                                                  |    |
                                                  |    |
       +--------------------------------------+   |    |
       |                                +---+ |   |    |
       |                                | 1 |<----+    |
       |        Chassis 2               +---+ |        |
       |                                +---+ |        |
       |                                | 2 |<----+    |
       |                                +---+ |   |    |
       +--------------------------------------+   |    |
                                                  |    |
                                                  |    |
       +--------------------------------------+   |    |
       |                                +---+ |   |    |
       |                                | 1 |<----+    |
       |        Chassis 3               +---+ |        |
       |                                +---+ |        |
       |                                | 2 |<---------+
       |                                +---+ |
       +--------------------------------------+

          Figure 6: Example of a stacked switch in a ring topology

   Using the base network inventory YANG data model, each stackable
   switch can be modelled as a chassis within the same network element,
   which models the stacked switch.  The stack ports are modelled like
   other ports.  The stack cables are not reported using the base
   network inventory YANG data model but can be reported using the
   passive network inventory YANG data model under definition in
   [I-D.ygb-ivy-passive-network-inventory].

   Cascaded switches are another example of multi-chassis which consist
   of multiple standalone switches that are interconnected and managed
   as a single logical unit.  Cascaded switch: - are usually connected
   in a tree topology - are managed using a single IP Address - the root
   of the tree is configured as Master.

   Figure 7 describe an example of cascaded switch with three chassis
   connected in a tree topology.

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           +----------------------------------------------+
           |  S1 |    Chassis 1      | S20 |        | S32 |
           |+---+|                   |     |        |+---+|
           || 1 ||                   |     |        || 1 ||
           |+---+|                   |     |        |+---+|
           | ... |                   |     |        |     |
           |+---+|                   |     |        |     |
     +----->| 4 ||                   |     |        | ... |
     |     |+---+|                   |     |        |     |
     |     |     |                   |     |        |     |
     |     |     |                   |     |        |+---+|
     |     |     |      ...          |     |   ...  || 6 |<-----+
     |     | ... |                   |     |        |+---+|     |
     |     |     |                   |     |        |     |     |
     |     |     |                   |     |        | ... |     |
     |     |     |                   |     |        |     |     |
     |     |+---+|                   |     |        |+---+|     |
     |     ||10 ||                   |     |        ||10 ||     |
     |     |+---+|                   |     |        |+---+|     |
     |     +----------------------------------------------+     |
     |                                                          |
     |                                                          |
     |  +-------------------------------+                       |
     |  |  S1 |     Chassis 2     | S16 |                       |
     |  |     |                   |     |                       |
     |  |     |                   |     |                       |
     |  |+---+|                   |     |                       |
     +---> 5 ||                   |     |                       |
        |+---+|                   |     |                       |
        |     |                   |     |                       |
        |     |                   |     |                       |
        +-------------------------------+                       |
                                                                |
                                                                |
                             +-------------------------------+  |
                             |  S1 |     Chassis 3     | S16 |  |
                             |     |                   |     |  |
                             |     |                   |     |  |
                             |     |                   |     |  |
                             |     |                   |+---+|  |
                             |     |                   || 7 |<--+
                             |     |                   |+---+|
                             |     |                   |     |
                             +-------------------------------+

         Figure 7: Example of a cascaded switch in a tree topology

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   Using the base network inventory YANG data model each interconnected
   switch can be modelled as a chassis within the same network element,
   which models the cascaded switch.  The ports used to interconnect the
   different chassis are normal (traffic) ports and modelled like other
   ports.  The interconnecting cables are not reported using the base
   network inventory YANG data model but can be reported using the
   passive network inventory model under definition in
   [I-D.ygb-ivy-passive-network-inventory].

E.1.  JSON Examples

   This appendix contains an example of an instance data tree in JSON
   encoding [RFC7951], instantiating the "ietf-network-inventory" model
   to describe the three examples of multi-chassis NEs, as shown in
   Figure 5, Figure 6 and Figure 7.

      Note: the base inventory model allows reporting only the chassis
      and ports configuration.  Reporting the link between the chassis
      of the same NE is outside the scope of the base inventory model.
      The YANG data model under definition in
      [I-D.ygb-ivy-passive-network-inventory] as an augmentation of the
      base inventory YANG data model can be used to provide this
      additional information.

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

   {
     "ietf-network-inventory:network-inventory": {
       "network-elements": {
         "network-element" : [
           {
             "ne-id": "NE-1",
             "description": "Stack Switch in a daisy chain topology.",
             "components": {
               "component": [
                 {
                   "component-id": "chassis-1",
                   "class": "iana-hardware:chassis",
                   "description": "First switch of the stack.",
                   "parent-rel-pos": 1,
                   "is-fru": true
                 },
                 {
                   "component-id": "port-1-1",
                   "class": "iana-hardware:port",
                   "description": "First stack port of the first \
                                                  switch in the stack.",
                   "parent": [

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                     "chassis-1"
                   ],
                   "parent-rel-pos": 1
                 },
                 {
                   "component-id": "port-1-2",
                   "class": "iana-hardware:port",
                   "description": "Second stack port of the first \
                                                  switch in the stack.",
                   "parent": [
                     "chassis-1"
                   ],
                   "parent-rel-pos": 2
                 },
                 {
                   "component-id": "transceiver-module-1-2",
                   "class": "iana-hardware:module",
                   "description": "Transceiver module plugged in the \
                   second stack port of the first switch in the stack.",
                   "parent": [
                     "port-1-2"
                   ],
                   "is-fru": true
                 },
                 {
                   "component-id": "chassis-2",
                   "class": "iana-hardware:chassis",
                   "description": "Second switch of the stack.",
                   "parent-rel-pos": 2,
                   "is-fru": true
                 },
                 {
                   "component-id": "port-2-1",
                   "class": "iana-hardware:port",
                   "description": "First stack port of the second \
                                                  switch in the stack.",
                   "parent": [
                     "chassis-2"
                   ],
                   "parent-rel-pos": 1
                 },
                 {
                   "component-id": "transceiver-module-2-1",
                   "class": "iana-hardware:module",
                   "description": "Transceiver module plugged in the \
                    first stack port of the first switch in the stack.",
                   "parent": [
                     "port-2-1"

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                   ],
                   "is-fru": true
                 },
                 {
                   "component-id": "port-2-2",
                   "class": "iana-hardware:port",
                   "description": "Second stack port of the second \
                                                  switch in the stack.",
                   "parent": [
                     "chassis-2"
                   ],
                   "parent-rel-pos": 2
                 },
                 {
                   "component-id": "transceiver-module-2-2",
                   "class": "iana-hardware:module",
                   "description": "Transceiver module plugged in the \
                   second stack port of the first switch in the stack.",
                   "parent": [
                     "port-2-2"
                   ],
                   "is-fru": true
                 },
                 {
                   "component-id": "chassis-3",
                   "class": "iana-hardware:chassis",
                   "description": "Third switch of the stack.",
                   "parent-rel-pos": 3,
                   "is-fru": true
                 },
                 {
                   "component-id": "port-3-1",
                   "class": "iana-hardware:port",
                   "description": "First stack port of the third \
                                                  switch in the stack.",
                   "parent": [
                     "chassis-3"
                   ],
                   "parent-rel-pos": 1
                 },
                 {
                   "component-id": "transceiver-module-3-1",
                   "class": "iana-hardware:module",
                   "description": "Transceiver module plugged in the \
                    first stack port of the third switch in the stack.",
                   "parent": [
                     "port-3-1"
                   ],

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                   "is-fru": true
                 },
                 {
                   "component-id": "port-3-2",
                   "class": "iana-hardware:port",
                   "description": "Second stack port of the second \
                                                  switch in the stack.",
                   "parent": [
                     "chassis-3"
                   ],
                   "parent-rel-pos": 2
                 }
               ]
             }
           },
           {
             "ne-id": "NE-2",
             "description": "Stack Switch in a ring topology.",
             "components": {
               "component": [
                 {
                   "component-id": "chassis-1",
                   "class": "iana-hardware:chassis",
                   "description": "First switch of the stack.",
                   "parent-rel-pos": 1,
                   "is-fru": true
                 },
                 {
                   "component-id": "port-1-1",
                   "class": "iana-hardware:port",
                   "description": "First stack port of the first \
                                                  switch in the stack.",
                   "parent": [
                     "chassis-1"
                   ],
                   "parent-rel-pos": 1
                 },
                 {
                   "component-id": "transceiver-module-1-1",
                   "class": "iana-hardware:module",
                   "description": "Transceiver module plugged in the \
                    first stack port of the first switch in the stack.",
                   "parent": [
                     "port-1-1"
                   ],
                   "is-fru": true
                 },
                 {

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                   "component-id": "port-1-2",
                   "class": "iana-hardware:port",
                   "description": "Second stack port of the first \
                                                  switch in the stack.",
                   "parent": [
                     "chassis-1"
                   ],
                   "parent-rel-pos": 2
                 },
                 {
                   "component-id": "transceiver-module-1-2",
                   "class": "iana-hardware:module",
                   "description": "Transceiver module plugged in the \
                   second stack port of the first switch in the stack.",
                   "parent": [
                     "port-1-2"
                   ],
                   "is-fru": true
                 },
                 {
                   "component-id": "chassis-2",
                   "class": "iana-hardware:chassis",
                   "description": "Second switch of the stack.",
                   "parent-rel-pos": 2,
                   "is-fru": true
                 },
                 {
                   "component-id": "port-2-1",
                   "class": "iana-hardware:port",
                   "description": "First stack port of the second \
                                                  switch in the stack.",
                   "parent": [
                     "chassis-2"
                   ],
                   "parent-rel-pos": 1
                 },
                 {
                   "component-id": "transceiver-module-2-1",
                   "class": "iana-hardware:module",
                   "description": "Transceiver module plugged in the \
                    first stack port of the first switch in the stack.",
                   "parent": [
                     "port-2-1"
                   ],
                   "is-fru": true
                 },
                 {
                   "component-id": "port-2-2",

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                   "class": "iana-hardware:port",
                   "description": "Second stack port of the second \
                                                  switch in the stack.",
                   "parent": [
                     "chassis-2"
                   ],
                   "parent-rel-pos": 2
                 },
                 {
                   "component-id": "transceiver-module-2-2",
                   "class": "iana-hardware:module",
                   "description": "Transceiver module plugged in the \
                   second stack port of the first switch in the stack.",
                   "parent": [
                     "port-2-2"
                   ],
                   "is-fru": true
                 },
                 {
                   "component-id": "chassis-3",
                   "class": "iana-hardware:chassis",
                   "description": "Third switch of the stack.",
                   "parent-rel-pos": 3,
                   "is-fru": true
                 },
                 {
                   "component-id": "port-3-1",
                   "class": "iana-hardware:port",
                   "description": "First stack port of the third \
                                                  switch in the stack.",
                   "parent": [
                     "chassis-3"
                   ],
                   "parent-rel-pos": 1
                 },
                 {
                   "component-id": "transceiver-module-3-1",
                   "class": "iana-hardware:module",
                   "description": "Transceiver module plugged in the \
                    first stack port of the third switch in the stack.",
                   "parent": [
                     "port-3-1"
                   ],
                   "is-fru": true
                 },
                 {
                   "component-id": "port-3-2",
                   "class": "iana-hardware:port",

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                   "description": "Second stack port of the second \
                                                  switch in the stack.",
                   "parent": [
                     "chassis-3"
                   ],
                   "parent-rel-pos": 2
                 },
                 {
                   "component-id": "transceiver-module-3-2",
                   "class": "iana-hardware:module",
                   "description": "Transceiver module plugged in the \
                   second stack port of the third switch in the stack.",
                   "parent": [
                     "port-3-2"
                   ],
                   "is-fru": true
                 }
               ]
             }
           },
           {
             "ne-id": "NE-3",
             "description": "Cascaded Switch in a tree topology.",
             "components": {
               "component": [
                 {
                   "component-id": "chassis-1",
                   "class": "iana-hardware:chassis",
                   "description": "First chassis of the cascaded switch\
                                                                     .",
                   "parent-rel-pos": 1,
                   "is-fru": true
                 },
                 {
                   "component-id": "slot-1-1",
                   "class": "iana-hardware:container",
                   "description": "Slot 1 of the first chassis of the \
                                                      cascaded switch.",
                   "parent": [
                     "chassis-1"
                   ],
                   "parent-rel-pos": 1
                 },
                 {
                   "component-id": "card-1-1",
                   "class": "iana-hardware:module",
                   "description": "Card plugged into slot 1 of the \
                                 first chassis of the cascaded switch.",

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                   "parent": [
                     "slot-1-1"
                   ],
                   "is-fru": true
                 },
                 {
                   "component-id": "port-1-1-1",
                   "class": "iana-hardware:port",
                   "description": "Empty port 1 on the card plugged \
              into slot 1 of the first chassis of the cascaded switch.",
                   "parent": [
                     "card-1-1"
                   ],
                   "parent-rel-pos": 1
                 },
                 {
                   "component-id": "port-1-1-4",
                   "class": "iana-hardware:port",
                   "description": "Pluggable port 4 on the card \
      plugged into slot 1 of the first chassis of the cascaded switch.",
                   "parent": [
                     "card-1-1"
                   ],
                   "parent-rel-pos": 4
                 },
                 {
                   "component-id": "transceiver-module-1-1-4",
                   "class": "iana-hardware:module",
                   "description": "Transceiver module plugged in port \
   4 on the card plugged into slot 1 of the first chassis of the \
                                                      cascaded switch.",
                   "parent": [
                     "port-1-1-4"
                   ],
                   "is-fru": true
                 },
                 {
                   "component-id": "port-1-1-10",
                   "class": "iana-hardware:port",
                   "description": "Empty port 10 on the card plugged \
              into slot 1 of the first chassis of the cascaded switch.",
                   "parent": [
                     "card-1-1"
                   ],
                   "parent-rel-pos": 10
                 },
                 {
                   "component-id": "slot-1-20",

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                   "class": "iana-hardware:container",
                   "description": "Empty slot 20 of the first chassis \
                                               of the cascaded switch.",
                   "parent": [
                     "chassis-1"
                   ],
                   "parent-rel-pos": 20
                 },
                 {
                   "component-id": "slot-1-32",
                   "class": "iana-hardware:container",
                   "description": "Slot 32 of the first chassis of the \
                                                      cascaded switch.",
                   "parent": [
                     "chassis-1"
                   ],
                   "parent-rel-pos": 32
                 },
                 {
                   "component-id": "card-1-32",
                   "class": "iana-hardware:module",
                   "description": "Card plugged into slot 32 of the \
                                 first chassis of the cascaded switch.",
                   "parent": [
                     "slot-1-32"
                   ],
                   "is-fru": true
                 },
                 {
                   "component-id": "port-1-32-1",
                   "class": "iana-hardware:port",
                   "description": "Empty port 1 on the card plugged \
             into slot 32 of the first chassis of the cascaded switch.",
                   "parent": [
                     "card-1-32"
                   ],
                   "parent-rel-pos": 1
                 },
                 {
                   "component-id": "port-1-32-6",
                   "class": "iana-hardware:port",
                   "description": "Pluggable port 6 on the card \
     plugged into slot 32 of the first chassis of the cascaded switch.",
                   "parent": [
                     "card-1-32"
                   ],
                   "parent-rel-pos": 6
                 },

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                 {
                   "component-id": "transceiver-module-1-32-6",
                   "class": "iana-hardware:module",
                   "description": "Transceiver module plugged in port \
   6 on the card plugged into slot 32 of the first chassis of the \
                                                      cascaded switch.",
                   "parent": [
                     "port-1-32-6"
                   ],
                   "is-fru": true
                 },
                 {
                   "component-id": "port-1-32-10",
                   "class": "iana-hardware:port",
                   "description": "Empty port 10 on the card plugged \
             into slot 32 of the first chassis of the cascaded switch.",
                   "parent": [
                     "card-1-32"
                   ],
                   "parent-rel-pos": 10
                 },
                 {
                   "component-id": "chassis-2",
                   "class": "iana-hardware:chassis",
                   "description": "Second chassis of the cascaded \
                                                               switch.",
                   "parent-rel-pos": 2,
                   "is-fru": true
                 },
                 {
                   "component-id": "slot-2-1",
                   "class": "iana-hardware:container",
                   "description": "Slot 1 of the second chassis of the \
                                                      cascaded switch.",
                   "parent": [
                     "chassis-2"
                   ],
                   "parent-rel-pos": 1
                 },
                 {
                   "component-id": "card-2-1",
                   "class": "iana-hardware:module",
                   "description": "Card plugged into slot 1 of the \
                                second chassis of the cascaded switch.",
                   "parent": [
                     "slot-2-1"
                   ],
                   "is-fru": true

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                 },
                 {
                   "component-id": "port-2-1-5",
                   "class": "iana-hardware:port",
                   "description": "Pluggable port 5 on the card \
     plugged into slot 1 of the second chassis of the cascaded switch.",
                   "parent": [
                     "card-2-1"
                   ],
                   "parent-rel-pos": 4
                 },
                 {
                   "component-id": "transceiver-module-2-1-5",
                   "class": "iana-hardware:module",
                   "description": "Transceiver module plugged in port \
   5 on the card plugged into slot 1 of the second chassis of the \
                                                      cascaded switch.",
                   "parent": [
                     "port-2-1-5"
                   ],
                   "is-fru": true
                 },
                 {
                   "component-id": "chassis-3",
                   "class": "iana-hardware:chassis",
                   "description": "Third chassis of the cascaded switch\
                                                                     .",
                   "parent-rel-pos": 3,
                   "is-fru": true
                 },
                 {
                   "component-id": "slot-3-1",
                   "class": "iana-hardware:container",
                   "description": "Empty slot 1 of the third chassis \
                                               of the cascaded switch.",
                   "parent": [
                     "chassis-3"
                   ],
                   "parent-rel-pos": 1
                 },
                 {
                   "component-id": "slot-3-16",
                   "class": "iana-hardware:container",
                   "description": "Slot 16 of the third chassis of the \
                                                      cascaded switch.",
                   "parent": [
                     "chassis-3"
                   ],

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                   "parent-rel-pos": 16
                 },
                 {
                   "component-id": "card-3-16",
                   "class": "iana-hardware:module",
                   "description": "Card plugged into slot 16 of the \
                                 third chassis of the cascaded switch.",
                   "parent": [
                     "slot-3-16"
                   ],
                   "is-fru": true
                 },
                 {
                   "component-id": "port-3-16-7",
                   "class": "iana-hardware:port",
                   "description": "Pluggable port 7 on the card \
     plugged into slot 16 of the third chassis of the cascaded switch.",
                   "parent": [
                     "card-3-16"
                   ],
                   "parent-rel-pos": 7
                 },
                 {
                   "component-id": "transceiver-module-3-16-7",
                   "class": "iana-hardware:module",
                   "description": "Transceiver module plugged in port \
   7 on the card plugged into slot 16 of the third chassis of the \
                                                      cascaded switch.",
                   "parent": [
                     "port-3-16-7"
                   ],
                   "is-fru": true
                 }
               ]
             }
           }
         ]
       }
     }
   }

Appendix F.  Example of non-modular network elements

   This appendix provides some examples of non-modular network elements
   and how they can be modelled using the "ietf-network-inventory"
   module defined in Section 5.

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   Non-modular network elements (also known as "pizza boxes") are
   network elements composed by a single chassis (with a 1U horizontal
   oriented rectangular shape) as a self-contained system.  A non-
   modular network element does not have any slots to take cards so it
   cannot take any non-field replaceable modules other than pluggable
   ports.

   Using the base network inventory YANG data model a non-modular
   network element can be modelled as a network element containing only
   one chassis and ports (as child components of the chassis).

   Reporting the single chassis component within a non-modular network
   element is required because the chassis component is the type of
   component which provides the physical characteristics of the network
   element chassis (the network element is defined just as an assembly
   of components) and its location, using the network inventory YANG
   data model under definition in
   [I-D.ietf-ivy-network-inventory-location].

F.1.  JSON Examples

   This appendix contains an example of an instance data tree in JSON
   encoding [RFC7951], instantiating the "ietf-network-inventory" module
   to describe an example of a non-modular network element.

   {
     "ietf-network-inventory:network-inventory": {
       "network-elements": {
         "network-element" : [
           {
             "ne-id": "Pizza-box-NE",
             "description": "Example of a pizza box NE.",
             "components": {
               "component": [
                 {
                   "component-id": "pizza-chassis",
                   "class": "iana-hardware:chassis",
                   "description": "Pizza box chassis.",
                   "is-fru": true
                 },
                 {
                   "component-id": "port-1",
                   "class": "iana-hardware:port",
                   "description": "Port 1 of the pizza box.",
                   "parent": [
                     "pizza-chassis"
                   ],
                   "parent-rel-pos": 1

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                 },
                 {
                   "component-id": "port-2",
                   "class": "iana-hardware:port",
                   "description": "Port 2 of the pizza box.",
                   "parent": [
                     "pizza-chassis"
                   ],
                   "parent-rel-pos": 2
                 },
                 {
                   "component-id": "port-3",
                   "class": "iana-hardware:port",
                   "description": "Port 3 of the pizza box.",
                   "parent": [
                     "pizza-chassis"
                   ],
                   "parent-rel-pos": 3
                 },
                 {
                   "component-id": "port-4",
                   "class": "iana-hardware:port",
                   "description": "Port 4 of the pizza box.",
                   "parent": [
                     "pizza-chassis"
                   ],
                   "parent-rel-pos": 4
                 },
                 {
                   "component-id": "port-5",
                   "class": "iana-hardware:port",
                   "description": "Port 5 of the pizza box.",
                   "parent": [
                     "pizza-chassis"
                   ],
                   "parent-rel-pos": 5
                 },
                 {
                   "component-id": "port-6",
                   "class": "iana-hardware:port",
                   "description": "Port 6 of the pizza box.",
                   "parent": [
                     "pizza-chassis"
                   ],
                   "parent-rel-pos": 6
                 },
                 {
                   "component-id": "port-7",

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                   "class": "iana-hardware:port",
                   "description": "Port 7 of the pizza box.",
                   "parent": [
                     "pizza-chassis"
                   ],
                   "parent-rel-pos": 7
                 },
                 {
                   "component-id": "port-8",
                   "class": "iana-hardware:port",
                   "description": "Port 8 of the pizza box.",
                   "parent": [
                     "pizza-chassis"
                   ],
                   "parent-rel-pos": 8
                 },
                 {
                   "component-id": "port-9",
                   "class": "iana-hardware:port",
                   "description": "Port 9 of the pizza box.",
                   "parent": [
                     "pizza-chassis"
                   ],
                   "parent-rel-pos": 9
                 },
                 {
                   "component-id": "port-10",
                   "class": "iana-hardware:port",
                   "description": "Port 10 of the pizza box.",
                   "parent": [
                     "pizza-chassis"
                   ],
                   "parent-rel-pos": 10
                 }
               ]
             }
           }
         ]
       }
     }
   }

Acknowledgments

   The authors of this document would like to thank the authors of
   [I-D.ietf-teas-actn-poi-applicability] for having identified the gap
   and requirements to trigger this work.

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   This document was prepared using kramdown.

Contributors

   Italo Busi
   Huawei Technologies
   Email: italo.busi@huawei.com

   Aihua Guo
   Futurewei Technologies
   Email: aihuaguo.ietf@gmail.com

   Victor Lopez
   Nokia
   Email: victor.lopez@nokia.com

   Bo Wu
   Huawei Technologies
   Email: lana.wubo@huawei.com

   Chenfang Zhang
   China Unicom
   Email: zhangcf80@chinaunicom.cn

   Oscar Gonzalez de Dios
   Telefonica
   Email: oscar.gonzalezdedios@telefonica.com

   Nigel Davis
   Ciena
   Email: ndavis@ciena.com

Authors' Addresses

   Chaode Yu
   Huawei Technologies
   Email: yuchaode@huawei.com

   Sergio Belotti
   Nokia

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   Email: sergio.belotti@nokia.com

   Jean-Francois Bouquier
   Vodafone
   Email: jeff.bouquier@vodafone.com

   Fabio Peruzzini
   FiberCop
   Email: fabio.peruzzini@fibercop.com

   Phil Bedard
   Cisco
   Email: phbedard@cisco.com

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