]> 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. The scope of this base model is set to be application- and technology-agnostic. However, the data model is designed with appropriate provisions to ease future augmentations with application-specific and technology-specific details. 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 This document defines 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 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 standards interfaces to retrieve and query network elements capabilities as recorded in an inventory are key enablers for many applications that consume network inventory data. From that standpoint and given the emergence of standard data models and their deployment by operators, the conventional function of inventory management is also required to be defined as a data model. For example, identifies a gap about the lack of a YANG data model 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). 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. 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 has been used as a reference for defining the YANG network inventory data model presented in this document. 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 . This base data model is technology-agnostic (that is, valid for IP/MPLS, optical, and microwave networks in particular) and can be augmented to include required 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 requirements for both hardware and software (but with base functions) use cases for Network Inventory. provides a set of augmentation considerations for future extensions of hardware, software, entitlement, and inventory topology mapping. The YANG data model defined in this document conforms to the Network Management Datastore Architecture .

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

Terminology and Notations

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

Terminology 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 .

Also, the document makes use of the following terms:

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 (chassis, card, port, etc.), software components (software-patch, bios, etc.), and boot-loader.

Board/Card:

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

Port:

An interface on a board.

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).

Tree Diagrams The meanings of the symbols in the YANG tree diagrams are defined in .

YANG Prefixes list the prefixes of the modules that are used in this document. Prefixes and corresponding YANG modules

Prefix	YANG Module	Reference
inet	ietf-inet-types
yang	ietf-yang-types
ianahw	iana-hardware
nwi	ietf-network-inventory	RFC XXXX

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 be defined under the component list node. Instead, they can be defined by augmenting the component-specific info container for the attributes applicable to HW e.g. boards/slot components only. Other component-specific attributes, such as SW-specific-info, may be defined in companion augmentation data models, such as and are out of the scope of this model.

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.

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. In order to support these use cases, this model is not aligned with 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).

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) 2024 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 2024-10-02 { 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 { base nwi:ne-type; description "A physical network element (NE). "; } /* * Groupings */ grouping common-entity-attributes { description "The set of attributes which are common to all the entities (e.g., component, network elements) defined in this module."; leaf uuid { type yang:uuid; config false; 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 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 "The textual description of the entity (e.g., component)."; } leaf alias { type string; description "The alias name of the entity (e.g., component). This alias name can be specified by network manager."; } leaf hardware-rev { type string; config false; description "The vendor-specific hardware revision string for the entity (e.g., component)."; } leaf software-rev { type string; config false; description "The vendor-specific software revision string for the entity (e.g., component)."; } leaf-list software-patch-rev { type string; config false; description "The vendor-specific patch software revision string for the entity (e.g., component)."; } leaf mfg-name { type string; config false; description "The name of the manufacturer of this entity (e.g., component)."; } leaf mfg-date { type yang:date-and-time; config false; description "The date of manufacturing of the entity (e.g., component)."; } leaf serial-number { type string; config false; 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 product-name { type string; config false; 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."; } } /* * Data Nodes */ container network-inventory { 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 { type identityref { base nwi:ne-type; } default "nwi:ne-physical"; config false; description "The NE type."; } uses common-entity-attributes; 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 "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; } } config false; mandatory true; description "The type of the component."; } uses common-entity-attributes { refine hardware-rev { 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"; } 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', 'firmware-rev', '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"; } refine mfg-date { description "The date of manufacturing of the managed component."; reference "RFC 6933: Entity MIB (Version 4) - entPhysicalMfgDate"; } } leaf firmware-rev { type string; config false; description "The vendor-specific firmware revision string for the component."; reference "RFC 6933: Entity MIB (Version 4) - entPhysicalFirmwareRev"; } leaf part-number { type string; config false; 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 asset-id { type string; config false; 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"; } 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 RFC 8348 or a list of sub-components as openconfig-platform."; } leaf parent-rel-pos { type int32 { range "0 .. 2147483647"; } config false; 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 RFC 8348 or a parent-component-references container as in draft-ietf-ccamp-network-inventory-yang-02."; } leaf is-fru { type boolean; config false; 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; config false; description "This node contains identification information about the component."; reference "RFC 6933: Entity MIB (Version 4) - entPhysicalUris"; } container chassis-specific-info { when "derived-from-or-self(../class, 'ianahw:chassis')"; config false; description "This container contains some attributes belong to chassis only."; } container slot-specific-info { when "derived-from-or-self(../class, 'ianahw:container')"; config false; description "This container contains some attributes belong to slot only."; } container board-specific-info { when "derived-from-or-self(../class, 'ianahw:module')"; config false; description "This container contains some attributes belong to board only."; } container port-specific-info { when "derived-from-or-self(../class, 'ianahw:port')"; config false; description "This container contains some attributes belong to port only."; } } } } } } } ]]>

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. 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. 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] 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-technology (packet over optical) scenario with a specific focus on the MPI (Multi-Domain Service Coordinator to Provisioning Network Controllers Interface)in the ACTN architecture. 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 The base Network Inventory YANG model defines the physical network elements (NEs) and hardware components of NEs. This document extends the base Network Inventory model for non-physical NEs (e.g., controllers, virtual routers, virtual firewalls) and software components (e.g., platform operating system (OS), software-patch).

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