]> Huawei Technologies

yuchaode@huawei.com

Nokia

sergio.belotti@nokia.com

Vodafone

jeff.bouquier@vodafone.com

TIM

fabio.peruzzini@telecomitalia.it

Cisco

phbedard@cisco.com

next generation unicorn sparkling distributed ledger This document defines a base YANG data model for network inventory that is application- and technology-agnostic. This data model can be augmented with application-specific and technology-specific details in other, more specific network inventory data models. About This Document The latest revision of this draft can be found at . Status information for this document may be found at . Source for this draft and an issue tracker can be found at .

Introduction The purpose of this document is to define a base network inventory YANG data model that is application- and technology-agnostic. The base data model can be augmented to describe application-specific or technology-specific information. Network Inventory management is a key component in operators' OSS architectures. Network Inventory is a fundamental functionality in network management and was specified many years ago. Given the emergence of data models and their deployment in operator's management and control systems, the traditional function of inventory management is also requested to be defined as a data model. Network Inventory management and monitoring is a critical part for ensuring the network stays healthy, well-planned, and functioning in the operator's network. Network Inventory management allows the operator to keep track of which physical devices are deployed in the network including relevant software and hardware versions. The Network Inventory management also helps the operator to know when to acquire new assets and what is needed, or to decommission old or faulty ones, which can help to improve network performance and capacity planning. In a gap was identified regarding the lack of a YANG data model that could be used at ACTN MPI interface level to report whole/partial network hardware inventory information available at domain controller level towards north-bound systems (e.g., MDSC or OSS layer). initial goal was to make possible the augmentation of the YANG data model with Network Inventory data model but this was never developed and the scope was kept limited to network topology data only. It is key for operators to drive the industry towards the use of a standard YANG data model for Network Inventory data instead of using vendors proprietary APIs (e.g., REST API). In the ACTN architecture, this would bring also clear benefits at MDSC level for packet over optical integration scenarios since this would enable the correlation of the HW network inventory information with the links information reported in the network topology model. This represent a priority for operators to implement this with a standard YANG data model that could be used as soon as possible in multi-vendor integrations of PNCs with MDSCs. The intention is to define a generic YANG base data model that would be as much as possible technology agnostic (valid for IP, optical and microwave networks) and that could be augmented, when required, to include some technology-specific inventory details together with specific HW or SW component’s attributes. 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 South Bound Interface (SBI) towards the network elements rather than at the domain controller's northbound. However, the YANG data model defined in has been used as a reference for defining the YANG network inventory data model presented in this draft. The proposed YANG data model has been analyzed at the present stage to cover the common requirements for both HW and SW use cases for Network Inventory. Network Inventory is a collection of data for network devices and their components managed by a specific management system. Per the definition of ,the network inventory model is a network model. This document defines one YANG module "ietf-network-inventory" in . provides a set of augmentation considerations for extensions of hardware, software, entitlement, and inventory topology mapping. The YANG data model defined in this document conforms to the Network Management Datastore Architecture .

Terminology and Notations The following terms are defined in and are not redefined here:

• client
• server
• augment
• data model
• data node

The following terms are defined in and are not redefined here:

• configuration data
• state data

The terminology for describing YANG data models is found in . TBD: Recap the concept of chassis/slot/component/board/... in . Following terms are used for the representation of the hierarchies in the network inventory. Network Inventory:

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

Network Element:

• a manageable network entity that contains hardware and software units, e.g. a network device installed on one or several chassis

Chassis:

• a holder of the device installation.

Slot:

• a holder of the board.

Component:

• a unit of the network element, e.g. hardware components like chassis, card, port, software components like software-patch, bios, and boot-loader

Board/Card:

• a pluggable equipment can be inserted into one or several slots/sub-slots and can afford a specific transmission function independently.

Port:

• an interface on board

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.

Requirements Notation 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 when, and only when, they appear in all capitals, as shown here.

Tree Diagram A simplified graphical representation of the data model is used in of this document. The meaning of the symbols in this diagram is defined in .

Prefix in Data Node Names In this document, names of data nodes and other data model objects are prefixed using the standard prefix associated with the corresponding YANG imported modules, as shown in the following table. Prefixes and corresponding YANG modules

Prefix	Yang Module	Reference
inet	ietf-inet-types
yang	ietf-yang-types
ianahw	iana-hardware
ni	ietf-network-inventory	RFC XXXX

RFC Editor Note: Please replace XXXX with the RFC number assigned to this document. Please remove this note.

YANG Data Model for Network Inventory Overview The network element definition is generalized to support physical devices and other types of inventory objects (e.g., virtual network elements) that can be managed as physical network elements from an inventory perspective. The data model for Network Element presented in this document uses a flat list of network element. 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. The component definition is also generalized to support any types of component, such as hardware, software, or firmware. 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. Attributes related to specific class of component can be found in the component-specific-info structure. 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-specific or technology- specific companion augmentation data models, such as . In , rack, chassis, slot, sub-slot, board and port are defined as components of network elements with generic attributes. While 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 network inventory information that a controller discovers from all the network elements under its control. However, the YANG data model defined in has been used as a reference for defining the YANG network inventory data model. This approach can simplify the implementation of this network inventory model when the controller uses the YANG data model defined in to retrieve the hardware from the network elements under its control.

Common Design for All Inventory Objects For all the inventory objects, there are some common attributes existing. Such as: Identifier: here we suggest to use uuid format which is widely implemented with systems. It is guaranteed to be globally unique. Name: name is a human-readable label information which could be used to present on GUI. This name is suggested to be provided by server. Alias: alias is also a human-readable label information which could be modified by user. It could also be present on GUI instead of name. Description: description is a human-readable information which could be also input by user. Description provides more detailed information to prompt users when performing maintenance operations.

Network Element To be consistent with the component definition, some of the attributes defined in for components are reused for network elements. These attributes include: Note: Not all the attributes defined in are applicable for network element. And there could also be some missing attributes which are not recognized by . More extensions could be introduced in later revisions after the missing attributes are fully discussed.

Components The YANG data model for network inventory mainly follows the same approach of and reports the network hardware inventory as a list of components with different types (e.g., chassis, module, port). The component definition is generalized to both hardware components and non-hardware components (e.g., software components). For state data like admin-state, oper-state and so on, we consider they are related to device hardware management and not network inventory. Therefore, they are outside of scope of this document. Same for the sensor-data, they should be defined in some other performance monitoring data models instead of inventory data model.

Hardware Components Based on TMF classification in , 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. The relationship between typical inventory objects in a physical network element can be described by below:

Relationship between typical inventory objects in physical network elements | /sub-slot | | | +--------------+ +-----------+ || ||1:N \/ +-----------+ | port | +-----------+ ]]>

The "iana-hardware" module defines YANG identities for the hardware component types in the IANA-maintained "IANA-ENTITY-MIB" registry. Some of the definitions taken from are actually based on the ENTITY-MIB . For the additional attributes of specific hardware, such as CPU, storage, port, power supply is defined in the hardware extension.

Software Components This document defines "software-rev" of NEs and components, which are basic software attributes of a Network Element. 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 .

Changes with respect to RFC8348 We re-defined some attributes listed in , based on some integration experience for network wide inventory data.

New Parent Identifiers' Reference provided a "parent-ref" attribute, which was an identifier reference to its parent component. When the MDSC or OSS systems want to find this component's grandparent or higher level component in the hierarchy, they need to retrieve this parent-ref step by step. To reduce this iterative work, we decided to provide a list of hierarchical parent components' identifier references. ../../../class | +--ro uuid? -> ../../../uuid ................................... ]]> The hierarchical components' identifier could be found by the "component-reference" list. The "index" attribute is used to order the list by the hierarchical relationship from topmost component (with the "index" set to 0) to bottom component.

Component-Specific Info Design According to the management requirements from operators, some important attributes are not defined in . These attributes could be component-specific and are not suitable to define under the component list node. So, the model can be augmented with HW/SW specific-info-grouping containing attributes applicable to HW e.g. boards/slot or SW e.g. software-module/boot-loader component only.

Part Number According to the description in , 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.

Extending Network Inventory This document defines the basic network inventory attributes applicable to typical network scenarios. For finer-grained and specific management scenarios, the relationship between this model and other models is illustrated in Figure 4.

Network Inventory Tree Diagram below shows the tree diagram of the YANG data model defined in module "ietf-network-inventory" ().

Network inventory tree diagram

YANG Data Model for Network Inventory

Network inventory YANG module WG List: Editor: Chaode Yu Editor: Sergio Belotti Editor: Jean-Francois Bouquier Editor: Fabio Peruzzini Editor: Phil Bedard "; description "This module defines a base model for retrieving network inventory. The model fully conforms to the Network Management Datastore Architecture (NMDA). Copyright (c) 2023 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.: replace XXXX with actual RFC number and remove this // note. // RFC Ed.: update the date below with the date of RFC publication // and remove this note. revision 2024-03-04 { description "Initial version"; reference "RFC XXXX: A YANG Data Model for Network Inventory."; //RFC Editor: replace XXXX with actual RFC number, update date //information and remove this note } 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 { base ni:ne-type; description "A physical network element (NE). "; } grouping common-entity-attributes { description "A set of attributes which are common to all the entities (e.g., component, equipment room) defined in this module."; leaf uuid { config false; type yang:uuid; description "Uniquely identifies an entity (e.g., component)."; } leaf name { type string; description "A name for an entity (e.g., component), as specified by a network manager, 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 description { type string; description "a textual description of inventory object"; } leaf alias { type string; description "a alias name of inventory objects. This alias name can be specified by network manager."; } } grouping ne-specific-info-grouping { description "Attributes applicable to network elements."; leaf hardware-rev { config false; type string; description "The vendor-specific hardware revision string for the NE."; } leaf software-rev { config false; type string; description "The vendor-specific software revision string for the NE."; } leaf mfg-name { config false; type string; description "The name of the manufacturer of this NE"; } leaf mfg-date { config false; type yang:date-and-time; description "The date of manufacturing of the NE."; } leaf serial-number { config false; type string; description "The vendor-specific serial number of NE. It is expected that vendors assign unique serial numbers to different NEs within the scope of the part number."; } leaf product-name { config false; type string; description "The vendor-specific serial number of the network element instance. It is expected that vendors assign unique serial numbers to different network element instances within the scope of the product name."; } } grouping component-specific-info-grouping { description "Provide component-specific attributes for different components."; container chassis-specific-info { when "../class = 'ianahw:chassis'"; description "This container contains some attributes belong to chassis only."; uses chassis-specific-info-grouping; config false; } container slot-specific-info { when "../class = 'ianahw:container'"; description "This container contains some attributes belong to slot only."; uses slot-specific-info-grouping; config false; } container board-specific-info { when "../class = 'ianahw:module'"; description "This container contains some attributes belong to board only."; uses board-specific-info-grouping; config false; } container port-specific-info { when "../class = 'ianahw:port'"; description "This container contains some attributes belong to port only."; uses port-specific-info-grouping; config false; } container software-specific-info { when "../class = 'ianahw:software'"; description "This container contains some attributes belong to software only."; uses software-specific-info-grouping; config false; } } grouping chassis-specific-info-grouping { //To be enriched in the future. description "Specific attributes applicable to chassis only."; } grouping slot-specific-info-grouping { //To be enriched in the future. description "Specific attributes applicable to slots only."; } grouping board-specific-info-grouping { //To be enriched in the future. description "Specific attributes applicable to boards only."; } grouping port-specific-info-grouping { //To be enriched in the future. description "Specific attributes applicable to ports only."; } grouping software-specific-info-grouping { //To be enriched in the future. description "Specific attributes applicable to software only."; } grouping ne-info-grouping { 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 "Network Element (NE) identifier."; } leaf ne-type { config false; type identityref { base ne-type; } default "ne-physical"; description "The type of network element (NE)."; } uses common-entity-attributes; uses ne-specific-info-grouping; 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."; leaf component-id { type string; description "Component identifier"; } leaf class { config false; type union { type identityref { base ianahw:hardware-class; } type identityref { base non-hardware-component-class; } } mandatory true; description "The type of the component."; } uses common-entity-attributes; container child-component-ref { config false; description "A placeholder for adding the reference to child component(s): to further discuss whether to define a child leaf-list as RFC8348 or a list of sub-components as openconfig-platform."; } leaf parent-rel-pos { config false; 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"; } container parent-component-ref { config false; description "A placeholder for adding the reference to parent component(s): to further discuss whether to define a parent attribute as RFC8348 or a parent-component-references container as in draft-ietf-ccamp-network-inventory-yang-02."; } leaf hardware-rev { config false; type string; description "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 firmware-rev { config false; type string; description "The vendor-specific firmware revision string for the component."; reference "RFC 6933: Entity MIB (Version 4) - entPhysicalFirmwareRev"; } leaf software-rev { config false; type string; description "The vendor-specific software revision string for the component."; reference "RFC 6933: Entity MIB (Version 4) - entPhysicalSoftwareRev"; } leaf serial-num { config false; type string; description "The vendor-specific serial number of the component instance. It is expected that vendors assign unique serial numbers to different component instances within the scope of the part number."; } leaf mfg-name { config false; type string; 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', 'firmware-rev', 'software-rev', and 'serial-num' 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 part-number { config false; 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 product-name { config false; type string; description "The vendor-specific and human-interpretable string describing the component type. It is expected that vendors assign unique product names to different component types within the scope of the vendor."; } leaf asset-id { config false; type string; description "This node is a user-assigned asset tracking identifier for the component. 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"; } leaf is-fru { config false; 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 mfg-date { config false; type yang:date-and-time; description "The date of manufacturing of the managed component."; reference "RFC 6933: Entity MIB (Version 4) - entPhysicalMfgDate"; } leaf-list uri { config false; type inet:uri; description "This node contains identification information about the component."; reference "RFC 6933: Entity MIB (Version 4) - entPhysicalUris"; } uses component-specific-info-grouping; } } } } } container network-inventory { uses ne-info-grouping; } } ]]>

Manageability Considerations <Add any manageability considerations>

Security Considerations <Add any security considerations>

IANA Considerations <Add any IANA considerations>

References Normative References TM Forum IANA n.d. This document defines a YANG data model for the management of hardware on a single server. Datastores are a fundamental concept binding the data models written in the YANG data modeling language to network management protocols such as the Network Configuration Protocol (NETCONF) and RESTCONF. This document defines an architectural framework for datastores based on the experience gained with the initial simpler model, addressing requirements that were not well supported in the initial model. This document updates RFC 7950. YANG is a data modeling language used to model configuration data, state data, Remote Procedure Calls, and notifications for network management protocols. This document describes the syntax and semantics of version 1.1 of the YANG language. YANG version 1.1 is a maintenance release of the YANG language, addressing ambiguities and defects in the original specification. There are a small number of backward incompatibilities from YANG version 1. This document also specifies the YANG mappings to the Network Configuration Protocol (NETCONF). The Network Configuration Protocol (NETCONF) defined in this document provides mechanisms to install, manipulate, and delete the configuration of network devices. It uses an Extensible Markup Language (XML)-based data encoding for the configuration data as well as the protocol messages. The NETCONF protocol operations are realized as remote procedure calls (RPCs). This document obsoletes RFC 4741. [STANDARDS-TRACK] In many standards track documents several words are used to signify the requirements in the specification. These words are often capitalized. This document defines these words as they should be interpreted in IETF documents. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements. RFC 2119 specifies common key words that may be used in protocol specifications. This document aims to reduce the ambiguity by clarifying that only UPPERCASE usage of the key words have the defined special meanings. This document captures the current syntax used in YANG module tree diagrams. The purpose of this document is to provide a single location for this definition. This syntax may be updated from time to time based on the evolution of the YANG language. This document introduces a collection of common data types to be used with the YANG data modeling language. This document obsoletes RFC 6021. This memo defines a portion of the Management Information Base (MIB) for use with network management protocols in the Internet community. In particular, it describes managed objects used for managing multiple logical and physical entities managed by a single Simple Network Management Protocol (SNMP) agent. This document specifies version 4 of the Entity MIB. This memo obsoletes version 3 of the Entity MIB module published as RFC 4133. Informative References TIM Vodafone Huawei Old Dog Consulting Cisco This document considers the applicability of Abstraction and Control of TE Networks (ACTN) architecture to Packet Optical Integration (POI)in the context of IP/MPLS and optical internetworking. It identifies the YANG data models defined by the IETF to support this deployment architecture and specific scenarios relevant to Service Providers. Existing IETF protocols and data models are identified for each multi-layer (packet over optical) scenario with a specific focus on the MPI (Multi-Domain Service Coordinator to Provisioning Network Controllers Interface)in the ACTN architecture. This document defines an abstract (generic, or base) YANG data model for network/service topologies and inventories. The data model serves as a base model that is augmented with technology-specific details in other, more specific topology and inventory data models. Data models provide a programmatic approach to represent services and networks. Concretely, they can be used to derive configuration information for network and service components, and state information that will be monitored and tracked. Data models can be used during the service and network management life cycle (e.g., service instantiation, service provisioning, service optimization, service monitoring, service diagnosing, and service assurance). Data models are also instrumental in the automation of network management, and they can provide closed-loop control for adaptive and deterministic service creation, delivery, and maintenance. This document describes a framework for service and network management automation that takes advantage of YANG modeling technologies. This framework is drawn from a network operator perspective irrespective of the origin of a data model; thus, it can accommodate YANG modules that are developed outside the IETF. Huawei China Mobile Huawei Orange This document defines the YANG model for network inventory software extensions to support more comprehensive software components and software-enabled network devices, e.g. virtual Provider Edge (PE), virtul Fire Wall (FW). This document augments the 'ietf-network-inventory' data model defined in xxx by adding the software components identification and new Network Element (NE) type.

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 . Since we have also reused the component concept of in our inventory data model, we can compare the component's attributes between "openconfig-platform" and our model directly , which is stated below: Comparison between openconfig platform and inventory data models

Attributes in oc-platform	Attributes in our model	remark
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
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	contained-child
chassis	chassis-specific-info
port	port-specific-info
power-supply		TBD
fan		Fan is considered as a specific board. And no need to define as a 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	board-specific-info
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

As it mentioned in 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.

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 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.

Acknowledgments The authors of this document would like to thank the authors of for having identified the gap and requirements to trigger this work. This document was prepared using kramdown.

Contributors Huawei Technologies

italo.busi@huawei.com

Futurewei Technologies

aihuaguo.ietf@gmail.com、

Nokia

victor.lopez@nokia.com

Huawei Technologies

lana.wubo@huawei.com

China Unicom

zhangcf80@chinaunicom.cn

Telefonica

oscar.gonzalezdedios@telefonica.com

Ciena

ndavis@ciena.com