Network Functions Virtualisation (NFV)

Introduction

NFV in ETSI

Founded in November 2012 by seven of the world's leading telecoms network operators, ETSI ISG NFV became the home of Network Functions Virtualisation (NFV).

Almost seven years and over 100 publications later, the ETSI ISG NFV community has evolved through several phases, its publications have moved from pre-standardization studies to detailed specifications (see Release documentation). The early Proof of Concepts (PoCs) efforts have evolved and led to a series of interoperability events (NFV Plugtests). This large community is still working intensely to develop the required standards for NFV transformation incorporating latest technologies, as well as sharing their experiences of NFV implementation and testing in multi-vendor environments.

ETSI ISG NFV, like any other ETSI Industry Specification Group is open to ETSI members and non-members alike, with different conditions depending on ETSI membership status. If you would like to participate in this work, please contact the NFV support team.

Building and Managing Softwarized Network Functions

Modern telecoms networks contain an ever-increasing variety of proprietary hardware. The launch of new services often demands network reconfiguration and on-site installation of new equipment which in turn requires additional floor space, power, and trained maintenance staff.

In a digital world, the innovation cycles accelerate and require greater flexibility and dynamism than hardware-based appliances allow. A hard-wired network with single functions boxes is tedious to maintain, slow to evolve, and prevent service providers from offering dynamic services.

In the same way that applications are supported by dynamically configurable and fully automated cloud environments, virtualized network functions allow networks to be agile and capable to respond automatically to the needs of the traffic and services running over it.

Key enabling technologies for this vision include SDN (Software Defined Networking) and NFV (Network Functions Virtualisation). SDN and NFV are complementary but increasingly co-dependent. While the former provides the means to dynamically control the network and the provisioning of networks as a service, the latter offers the capability to manage and orchestrate the virtualization of resources for the provisioning of network functions, either deployed in virtual machines or OS containers, and their composition into higher-layer network services.

Our Role & Activities

Overview

ETSI ISG NFV undertakes work in 2-year phases.

Documents published during the first phase (2013-2014) were considered as pre-standard studies and are sometimes referred to as “Release 1”.

The ISG NFV community has continued its work by developing normative specifications, as well as informative studies. The specification of new features and capabilities in planned releases had as outcome subsequent tranches referenced as "Release 2", "Release 3", etc.

Going forward, the ISG NFV continues to develop new specifications that meet the needs of the industry, with maintenance cycles for its already published specifications. The ISG NFV dedicates a continuous support for proper referencing of NFV specifications by industry stakeholders, including not only service providers or network equipment vendors, but also other implementers such as open-source communities. Progress in the industry is continuously monitored, including feedback from implementations, open-source communities, and other standards bodies, and the identification of gaps to be addressed.

Abbreviations of the NFV working groups mentioned in this page:

* The REL working group has merged with IFA and TST has merged with the SOL Working Groups.

Started 2023: NFV Release 6

Release 6 focuses on architecture and infrastructure with interfaces, modeling, etc. to extend current features and new features such as (not exhaustive list):

• Architecture evolution and simplification.
• New infrastructure.
• New virtualization forms.
• Latency aspects.

Started 2021: NFV Release 5

NFV Release 5 builds on top and leverages the results of ETS ISG NFV documents published as part of the Release 4. The Release 5 introduces new features on top of the specified capabilities and features in previous Releases and continues features not completed in Release 4.

• Network connectivity integration and operationalization for NFV - container networking enhances the NFV architectural framework to provide support for multiple networks connectivity for OS container-based VNF.
• NFV-MANO automation and autonomous networks, the scope of the feature covers the following areas: NFV-MANO support for managing autonomous networks, enabling higher level of automation for NFV-MANO, intent-based principles for external exposure network services management.
• NFV enhancements for 5G, the feature enhances the NFV architectural framework to further support 5G network deployments.
• Multi-tenancy enhancements for NFV-MANO, the scope of the feature covers the following areas: multi-tenancy technology to share IT resources securely among multiple tenants that use the cloud, virtualization-based features as a means to isolate tenants, association/disassociation of tenancy and NFV-MANO objects, definition of isolation expectations of tenants, management of tenants.
• VNF generic management functions, the feature analyses and defines the type of OAM functions for VNFs that can be generalized and be provided as a "generic function" supporting the provisioning, connectivity, configuration, testing and monitoring of VNFs on a virtualized platform.
• Policy management models, the feature defines the models necessary for policy management, while the architectural enhancements for the introduction of the policy framework and the specification of a policy engine, with its procedures, interfaces and handling of the input events, goals and output/actions is not in scope of this feature.
• NFV for vRAN, The scope of this feature covers the following areas: study the advances concerning the virtualization of the RAN and profile the NFV framework to determine how it can support virtualized RAN (vRAN) use cases, • identify key technical challenges relevant to architectural, operational and management aspects, in case the NFV architectural framework is leveraged to support virtualization of the RAN, • provide recommendations for enhancements to the NFV architectural framework and its functionality, aiming to provide further support for vRAN use cases, • based on the recommendations, enhance when needed the overall NFV-MANO framework, existing NFV-MANO interfaces and descriptors.
• Green NFV, the scope of the feature covers the following areas: analyse aspects of NFV (VNF design, NFV-MANO and VNF operation, deployment configuration of NFV-MANO, NFVI, etc.) that have impact on energy consumption and those that can enable smart energy NFV and power saving features, identify design guidelines needed for optimizing energy consumption, specify enhancements to specifications on interfaces and information model, augment exposed KPIs and metrics to enable resources orchestration and VNF/NS LCM to operate following power saving policies.
• VNF configuration, the scope of this feature covers the following areas: provide guidelines on the use of the configuration options available in the NFV framework and the types of configuration data applicable to each of these options, specify related enhancements to the set of ETSI NFV specifications needed to improve interoperability between VNFs and independently-developed VNF configuration management functions and further facilitate automation of VNF configuration.
• Flexible VNF deployment, the feature has two parts: deployable modules and dynamic capacity. The deployable modules part was added late to Release 4. The dynamic capacity part introduces support for parameterizing the VDU attributes related to capacity in the interfaces.
• Physical Infrastructure Management, the scope of the feature covers the following areas: define requirements for physical infrastructure management in the NFV-MANO framework, provide a common information model for describing hardware attributes and statuses, and specify operations for managing infrastructure hardware with respect to life cycle and FCAPS of physical resources, profile existing solutions related to hardware management.
• VNF management gaps with Open Source, will produce a report on VNF management gap analysis with open source projects.

The "Release 5 Definition" lists all the new features proposed for the Release 5.

Similarly, as in the previous Release, the completion of the specification of features in Release 5 at different stages follows a phased approach, commonly referred to as "drops".

Started 2019: NFV Release 4

NFV Release 4 specification work has been formally launched in summer 2019. While the specific work items are under progress, key areas of focus for the future NFV Release 4 have been identified, which include:

• NFVI evolution, focusing on enhancements to support lightweight virtualization technologies such as OS containers, optimizing NFV Infrastructure (NFVI) abstraction for reducing the coupling of VNFs to infrastructure, and optimizing networking integration into the infrastructure fabric to ease the connectivity for Virtualized Network Functions (VNFs) and Network Services (NSs)
• Enhancing NFV automation and capabilities, covering aspects such as: improving life-cycle management and orchestration, introducing more policy-based management, the simplification of VNF and NS management aspects leveraging virtualization, and handling advances in autonomous networking
• Evolving the NFV-MANO (Management and Orchestration) framework, focusing primarily on optimizing internal NFV-MANO capability exposure and usage, e.g. studying its service-based transformation
• Enhanced reliability and availability introduced via features like NFV-MANO upgrades and MANO robustness
• Accompanying operationalization aspects which include: the simplification of NFV to ease development and deployment of sustainable NFV based solutions, verification (and certification) procedures and mechanisms, and operationalization, integration and use of NFV with other management and network frameworks
• In addition to the above technical areas, several security hardening aspects of NFV and other small specific technical enhancements necessary to maximize the impact of virtualization and future NFV deployments are also expected to be part of the work programme

The "Release 4 Definition" lists all the new features proposed for the Release 4.
List of new features in Release 4:

• Network connectivity integration and operational for NFV
• NFV-MANO automation and autonomous networks
• NFV enhancements for 5G
• Multi-tenancy enhancements for NFV-MANO
• Service-based architecture (SBA) for NFV-MANO
• VNF generic management functions
• Continuous VNF integration, and
• Policy models

The set of Release 3 features that had been carried over into Release 4 (had not been fully completed in Release 3) comprises:

• NFV-MANO software modification
• Multi-access Edge Computing (MEC) in NFV
• Licensing management
• Cloud-native VNFs and container infrastructure management, and
• Security management

Similarly to all the Releases, the completion of the specification of features in Release 4 at different stages follows a phased approach, commonly referred to as "drops". The specification work on the main/core set of specifications and features, up to stage 3, was fully completed in 2023, with additional rounds of maintenance delivered until 1Q2024. The latest version of the core specification set of Release 4 is v4.6.1.

Started 2017: NFV Release 3

NFV Release 3 has focused on enriching the NFV Architectural Framework to make NFV “ready” for global deployment and operations. The feature collection period to build Release 3 in 2017 led to a set of 22 new features. By summer 2019, 10 features had been completed, and 2 features had been partly completed to the level of specifying architecture, interfaces and information model. Some features had been closed, and some others were carried over to Release 4.

The set of features for Release 3 can be categorized into three main areas:

• Support for the latest network technologies, such as edge computing and network slicing
• New operational aspects, such as multiple administrative domains, policy framework, management of NFV-MANO, software upgrades/updates of the VNF and of the NFVI, etc.
• Advances in virtualization, such as cloud native VNFs, acceleration technologies, etc.

The "Release 3 Description" provides the list of features that are part of the Release, the relevant technical scope that has been specified, and the corresponding group reports and specifications that have been either updated or newly documented as part of the Release 3 feature work.

The specification work of architecture, interfaces and information model was completed during summer 2019. Below is the set of completed features that Release 3 brings on top of the features and capabilities that had been already specified in Release 2:

• Interfaces for hardware-independent acceleration
• Interfaces for network acceleration for VNF
• Requirements for hypervisor-based virtualisation
• Requirements for the hardware environment in NFV
• Management of NFV-MANO functional entities
• VNF snapshotting
• Policy management framework
• NFV-MANO administrative domains
• Host reservation
• Management and connectivity of multi-site network services
• Network slicing in NFV
• VNF software modification (aka, change current VNF package)
• NFVI software modification
• Service availability level
• Secure sensitive components in NFV framework
• Security management and monitoring for NFV

The specification of protocols and data model solutions was fully completed in early 2022, as part of the so-called “package 21H2” of Release 3 stage 3 specifications. An additional and last published version of Release 3 specs for protocols and data models was done by the end of 2022 with published versions v3.7.1 of several of the specifications. Note that the publication of additional testing specifications (aka stage 4) took place during 2023.

Started 2015: NFV Release 2

The need to produce normative specifications to enable end-to-end interworking of equipment and services formed a fundamental part of this phase.

The ISG NFV decided to group most of its normative work into "NFV Release 2". Many other reports were also produced, so the Release 2 documentation became a subset of the actual work during the 2015-2016 phase. The work covered the common specification stages of requirements, architecture, interfaces, and information models and protocols all the way through to the specification of test cases and suites.

Release 2 was defined by selecting and prioritizing a set of key capabilities for making NFV deployable at scale yet ensuring the interoperability of NFV solutions used therein.

The main technical focus of Release 2 covered the specification of models and interfaces concerning diverse capabilities (as listed below) for the interoperability across the NFV-MANO functional blocks (VIM, VNFM and NFVO) and towards external systems, according to the reference points specified in the NFV Architectural Framework.

The set of capabilities specified in Release 2 comprises:

• Management aspects concerning virtualized resources, including information, provisioning, reservation, capacity, performance and fault management. This scope of management concerns to the functionality produced by the VIM and exposed over the Or-Vi and Vi-Vnfm reference points
• Lifecycle management, fault, configuration and performance management of VNFs. This management functionality is offered by the VNFM as a producer entity and exposed over the Or-Vnfm and Ve-Vnfm reference points
• Lifecycle management, fault and performance management of Network Services. This functionality is produced by the NFVO and exposed over the Os-Ma-nfvo reference point
• Performance metrics associated to virtualised resources, VNF and NS
• VNF Package management, which is produced by the NFVO and exposed over the Or-Vnfm and Os-Ma-nfvo reference points
• Software image management
• VNF information modelling, including the VNF Descriptor and VNF Packaging
• NS information modelling, which covers the NS Descriptor, VNF Forwarding Graphs and PNF Descriptors
• Hardware-independent acceleration

The ISG NFV documentation of requirements, interfaces and architecture (aka stage 2), which mostly uses the acronym NFV-IFA (standing for “NFV Interfaces and Architecture”) is distributed as follows:

• NFV-IFA010 specifies the functional requirements of NFV-MANO and its functional blocks covering the set of capabilities listed above
• NFV-IFA005, NFV-IFA006, NFV-IFA007, NFV-IFA008, NFV-IFA013 specify the requirements and interfaces covering the functionalities listed above, considering the scope of functionality of the respective producer NFV-MANO functional blocks and the reference points
• NFV-IFA027 specifies the performance metrics regarding virtualised resources, VNF and NS
• NFV-IFA002, NFV-IFA003 and NFV-IFA004 specify aspects related to hardware-independent acceleration
• NFV-IFA011 and NFV-IFA014 specify requirements and information modelling of NFV descriptors and artefacts, such as the VNFD, VNF Packaging and NSD.
• NFV-IFA015, NFV-IFA016 and NFV-IFA017 consolidate the UML information modelling and the associated modelling guidelines of information elements that have been developed in other reference points specifications (see above). Touchpoints in between the NFV IM and external organization’s information models are documented in NFV-IFA024

In terms of protocols and data models specifications (aka stage 3), which use the acronym NFV-SOL (standing for “NFV Solutions”), REST-based APIs have been specified covering the functionalities of the interfaces specified on the reference points Os-Ma-nfvo (in between the OSS/BSS and NFVO) (refer to NFV-SOL005), Or-Vnfm (in between the NFVO and VNFM) (refer to NFV-SOL003), and Ve-Vnfm (in between the VNF/EM and VNFM) (refer to NFV-SOL002). As part of the security enhancements required for authorizing the access to the APIs, additional provisions have been specified (refer to NFV-SEC022), which is referred by the "Specification of common aspects for RESTful NFV-MANO APIs" (refer to NFV-SOL013).

For the NFV descriptors (such as VNFD and NSD), two data model solutions have been specified. The first leverages the “OASIS TOSCA Simple Profile in YAML” specification (refer to NFV-SOL001), and the second provides a YANG-based representation (refer to NFV-SOL006). And finally, in terms of other NFV artefacts, the VNF and PNF Packaging (NFV-SOL004) and NSD file structure specifications (NFV-SOL007) leverage the OASIS Cloud Service Archive (CSAR) format specification. For the case of the NFV artefacts, additional security enhancements are also specified, for the VNF Packaging (refer to NFV-SEC021).

Committing to providing high quality specifications to ensure broad and rapid adoption of NFV standards by the industry, OpenAPITM representations of the RESTful NFV-MANO APIs have been provided since versions V2.4.1 of the respective specification, available on the ETSI NFV public wiki.

As the final step in the specification process, relevant NFV-TST (standing for “NFV Testing”) specifications are the "Guidelines on Interoperability Testing for MANO" (NFV-TST007) and the "API Conformance Testing Specification" (NFV-TST010).

In addition to the documents listed above, ETSI NFV has produced many more specifications and reports on topics such as reliability (documents which use the acronym NFV-REL, standing for “NFV Reliability and Availability”), security (using the acronym NFV-SEC) and NFV evolution and its ecosystem (documents using the NFV-EVE, standing for “NFV Evolution and Ecosystem”), such as studies to address new use cases, interworking with other technologies, etc.

Furthermore, it is worth highlighting that as part of improving the published specifications and addressing feedback from implementations, Release 2 specifications have gone through several rounds of maintenance, typically republishing specifications twice a year. The latest version of published specifications concerning protocols and data models was delivered in October 2020. Furthermore, in 2020, the set of Release 2 specifications was augmented with a specification of end-to-end NFV-MANO procedures  (NFV-SOL016) and a YAML data model specification for descriptor-based virtualised resource management on the Or-Vi and Vi-Vnfm reference points (NFV-SOL014).

For an introduction to the Release 2 content and additional description about the capabilities that have been specified, see also the NFV Release 2 description document, available in the ISG NFV "Open" area.

2013-2014: Early Phase

The initial focus in the first two years of the ISG NFV was to help the industry build a culture and share a common understanding on the important concepts in network virtualization. The work started in direct response to address the technical challenges of network virtualization that were highlighted in the original vision outlined in the joint-operator white paper published in October 2012. The resulting “pre-standardization” documents were set:

• to drive convergence on network operator requirements for NFV
• to include applicable standards, where they already exist, into industry services and products
• to simultaneously develop new technical requirements with the goal of stimulating innovation and fostering an open ecosystem of vendors

The first important milestone was the publication of the first five ETSI Group Specifications (GSs) documents in October 2013. Four of them were designed to align understanding about NFV across the industry. They covered NFV use cases (NFV 001), virtualization requirements (NFV 004), an architectural framework (NFV 002), and terminology (NFV 003). The fifth one defined a framework for co-ordinating and promoting public demonstrations of Proof of Concept (PoC) platforms illustrating key aspects of NFV (NFV-PER 002).

In 2014, the publication pace accelerated with the release of 11 other documents focusing in different technical areas such as NFV Infrastructure, including compute, hypervisor and network resources (with documents tagged as "NFV-INF"), NFV management and orchestration (tagged as "NFV-MAN"), the architecture of the VNF (tagged as "NFV-SWA"), and associated functional and non-functional security, reliability and performance areas.

Upcoming meetings

NFV #46 will be held between June 3rd to 7th 2024 in Xi'an China.

Specifications

With over 100 NFV publications and over 50 draft specifications in progress it can be tricky to find a document. In order to assist you please find the following guidelines:

Search for publications by Working Group: SOL, IFA, EVE, SEC (including closed WGs: SWA, MAN, PER, INF, TST, REL).

Search for all ISG NFV publications.

Search for specifications within the NFV Architecture Framework:

Find publicly available NFV specifications via the NFV committee page, and subscribe for alerts on updates of specifications.

Search for Drafts in progress via the ETSI Work Programme.

In addition to the published specifications, ISG NFV makes all of its drafts in progress publicly available for industry comment.

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