Network function virtualization: Difference between revisions

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Revision as of 03:02, 1 April 2021

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NFV relies upon, but differs from, traditional server-[[virtualization]] techniques, such as those used in enterprise IT. A virtualized network function, or VNF, may consist of one or more [[virtual machines]] or [[OS-level virtualization|containers]] running different software and processes, on top of standard high-volume servers, switches and storage devices, or even [[cloud computing]] infrastructure, instead of having custom hardware appliances for each network function.

For example, a virtual [[session border controller]] could be deployed to protect a network without the typical cost and complexity of obtaining and installing physical network protection units. Other examples of NFV include virtualized [[Network Load Balancing|load balancers]], [[Firewall (computing)|firewalls]], [[Intrusion detection system|intrusion detection devices]] and [[WAN optimization|WAN accelerators]].<ref>{{cite web|title=Network Functions Virtualisation (NFV); Use NFV is present and SDN is future.Cases|url=http://www.etsi.org/deliver/etsi_gs/NFV/001_099/001/01.01.01_60/gs_NFV001v010101p.pdf|access-date=6 June 2014}}</ref>

==Background==

Product development within the telecommunication industry has traditionally followed rigorous standards for stability, protocol adherence and quality, reflected by the use of the term [[carrier grade]] to designate equipment demonstrating this reliability.<ref>{{cite journal|url=https://www.wired.com/insights/2013/03/how-low-cost-telecom-killed-five-9s-in-cloud-computing/ |title=How Low-Cost Telecom Killed Five 9s in Cloud Computing |journal=Wired |publisher=wired.com |date= 2013-03-13|access-date=2016-06-27|last1=OpengearStephenson |first1=Rick Stevenson }}</ref> While this model worked well in the past, it inevitably led to long product cycles, a slow pace of development and reliance on proprietary or specific hardware, e.g., bespoke [[application-specific integrated circuit]]s (ASICs). The rise of significant competition in communication services from fast-moving organizations operating at large scale on the public Internet (such as [[Google Talk]], [[Skype]], [[Netflix]]) has spurred service providers to look for ways to disrupt the status quo.

==History==

In October 2012, a group of telecom operators published a [[white paper]]<ref name="white">{{cite web |title=Network Functions Virtualization— Introductory White Paper |publisher= ETSI |date= 22 October 2012 |url= https://docbox.etsi.org/isg/nfv/open/Publications_pdf/White%20Papers/NFV_White_Paper1_2012.pdf |access-date= 20 June 2013 }}</ref> at a conference in [[Darmstadt, Germany]], on [[software-defined networking]] (SDN) and [[OpenFlow]]. The Call for Action concluding the White Paper led to the creation of the Network Functions Virtualization (NFV) Industry Specification Group (ISG) <ref>{{cite web |title = Network Functions Virtualisation |work= ETSI Standards for NFV |url= https://www.etsi.org/technologies/nfv |access-date= 30 June 2020 }}</ref> within the [[European Telecommunications Standards Institute]] (ETSI). The ISG was made up of representatives from the telecommunication industry from Europe and beyond.<ref>{{Cite news |title= Tier 1 Carriers Tackle Telco SDN |date= 22 October 2012 |authorfirst1= Ray |last1=Le Maistre |work= Light Reading |url= http://www.lightreading.com/software-defined-networking/tier-1-carriers-tackle-telco-sdn/240135217 |access-date= 20 June 2013 }}</ref><ref>{{cite web |title= Latest Agenda at SDN & OpenFlow World Congress |publisher= Layer123.com |url-status=dead |url= http://www.layer123.com/sdn-agenda/ |archive-date= October 14, 2012 |archive-url= https://web.archive.org/web/20121014053339/http://www.layer123.com/sdn-agenda/ |access-date= 20 June 2013}}</ref> Since the publication of the white paper, the group has produced over 100 publications.<ref>{{cite web |title=Standards for NFV: Network Functions Virtualisation |publisher= NFV Solutions |url=https://www.etsi.org/technologies/nfv |website=ETSI |language=en-gb}}</ref> In 2016, one high performance open source version of NFV is released. openNetVM is a high performance NFV platform based on DPDK and Docker containers.<ref>{{cite journal|url=http://faculty.cs.gwu.edu/timwood/papers/16-HotMiddlebox-onvm.pdf |title=OpenNetVM: A Platform for High Performance Network Service Chains|doi=10.1145/2940147.2940155|s2cid=13706879}}</ref>

==Framework==

The NFV framework consists of three main components:<ref>{{cite web |title=Network-Functions Virtualization (NFV) Proofs of Concept; [http|url=https://www.etsi.org/technologies-clusters/technologiesnfv/nfv Framework], GS NFV-PER 002 v1.1.1 (2013-10),poc}}</ref>

# Virtualized network functions (VNFs) are software implementations of network functions that can be deployed on a network functions virtualization infrastructure (NFVI).<ref>{{cite web|url=http://blog.datapath.io/network-function-virtualization-nfv|title=What is Network Function Virtualization (NFV)|work=blog.datapath.io|access-date=2017-01-20|archive-url=https://web.archive.org/web/20170201235153/http://blog.datapath.io/network-function-virtualization-nfv|archive-date=2017-02-01|url-status=dead}}</ref>

# Network functions virtualization infrastructure (NFVI) is the totality of all hardware and software components that build the environment where NFVs are deployed. The NFV infrastructure can span several locations. The network providing connectivity between these locations is considered as part of the NFV infrastructure.

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A service provider that follows the NFV design implements one or more virtualized network functions, or ''VNFs''. A VNF by itself does not automatically provide a usable product or service to the provider's customers. To build more complex services, the notion of ''service chaining'' is used, where multiple VNFs are used in sequence to deliver a service.

Another aspect of implementing NFV is the ''orchestration'' process. To build highly reliable and scalable services, NFV requires that the network be able to instantiate VNF instances, monitor them, repair them, and (most important for a service provider business) bill for the services rendered. These attributes, referred to as carrier-grade<ref name="CG">Don’t{{cite web|title=Don't Confuse ‘High"High Availability’Availability" with ["Carrier Grade" | url=http://embedded.communities.intel.com/community/en/blog/2014/04/04/don-t-confuse-high-availability-with-carrier-grade Carrier Grade] {{Webarchive|archive-url=https://web.archive.org/web/20170703015358/https://embedded.communities.intel.com/community/en/blog/2014/04/04/don-t-confuse-high-availability-with-carrier-grade |archive-date=2017-07-03 }}, |publisher=Embedded Community, |first1=Charlie |last1=Ashton, |date=April, 2014}}</ref> features, are allocated to an orchestration layer in order to provide high availability and security, and low operation and maintenance costs. Importantly, the orchestration layer must be able to manage VNFs irrespective of the underlying technology within the VNF. For example, an orchestration layer must be able to manage an [[Session border controller|SBC]] VNF from vendor X running on [[VMware]] [[vSphere]] just as well as an [[IP Multimedia Subsystem|IMS]] VNF from vendor Y running on KVM.

==Distributed NFV==

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In essence, software-defined networking (SDN) is an approach to building data networking equipment and software that separates and abstracts elements of these systems. It does this by decoupling the control plane and data plane from each other, such that the control plane resides centrally and the forwarding components remain distributed. The control plane interacts both [[Northbound interface|northbound]] and [[Southbound interface|southbound]]. In the northbound direction the control plane provides a common abstracted view of the network to higher-level applications and programs using APIs. In the southbound direction the control plane programs the forwarding behavior of the data plane, using device level APIs of the physical network equipment distributed around the network.

Thus, NFV is not dependent on SDN or SDN concepts. It is entirely possible to implement a virtualized network function (VNF) as a standalone entity using existing networking and orchestration paradigms. However, there are inherent benefits in leveraging SDN concepts to implement and manage an NFV infrastructure, particularly when looking at the management and orchestration of VNFs, and that's why multivendor platforms are being defined that incorporate SDN and NFV in concerted ecosystems.<ref>[{{cite web|url=http://www.cisco.com/go/esp |title=Platform to Multivendor Virtual and Physical Infrastructure]}}</ref>

An NFV infrastructure needs a central orchestration and management system that takes operator requests associated with a VNF, translates them into the appropriate processing, storage and network configuration needed to bring the VNF into operation. Once in operation, the VNF potentially must be monitored for capacity and utilization, and adapted if necessary.<ref>{{Cite book|url=http://eu.wiley.com/WileyCDA/WileyTitle/productCd-1118900286.html|title=Software Defined Mobile Networks (SDMN): Beyond LTE Network Architecture.|last=Liyanage|first=Madhusanka|publisher=John Wiley|year=2015|isbn=978-1-118-90028-4|___location=UK|pages=1–438}}</ref>

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==Industry impact==

NFV has proven a popular standard even in its infancy. Its immediate applications are numerous, such as virtualization of [[mobile base station]]s, [[platform as a service]] (PaaS), [[content delivery network]]s (CDN), fixed access and home environments.<ref>{{cite web|title=Network Functions Virtualization (NFV) [Use Cases|url=http://www.etsi.org/deliver/etsi_gs/NFV/001_099/001/01.01.01_60/gs_NFV001v010101p.pdf Use Cases], ETSI GS NFV 001 v1.1.1 (2013-10)}}</ref> The potential benefits of NFV is anticipated to be significant. Virtualization of network functions deployed on general purpose standardized hardware is expected to reduce capital and operational expenditures, and service and product introduction times.<ref name="benefits">What’s{{cite [web|title=What's NFV – Network Functions Virtualization?|url=http://www.sdncentral.com/whats-network-functions-virtualization-nfv/ NFV] – Network Functions Virtualization?, |publisher=SDN Central}}</ref><ref>{{cite web|title=Carrier Network [Virtualization|url=http://carriernetworkvirtualization.com/company/network-functions-virtualisation-isg-nfv-etsi/ Virtualization], |publisher=ETSI news}}</ref> Many major network equipment vendors have announced support for NFV.<ref>{{Cite news |title= Openwave Exec Discusses the Benefits, Challenges of NFV & SDN |work= Article |url= http://www.sdnzone.com/topics/software-defined-network/articles/359936-openwave-exec-discusses-benefits-challenges-nfv-sdn.htm |date= 12 November 2013 |access-date= 22 November 2013 |archive-url= https://web.archive.org/web/20160303214633/http://www.sdnzone.com/topics/software-defined-network/articles/359936-openwave-exec-discusses-benefits-challenges-nfv-sdn.htm |archive-date= 3 March 2016 |url-status= dead }}</ref> This has coincided with NFV announcements from major software suppliers who provide the NFV platforms used by equipment suppliers to build their NFV products.<ref>[{{cite web|url=http://www.serviceprovideritreport.com/author.asp?section_id=3098 |title=Middleware] for the NFV Generation, |publisher=Service, LeeProvider IT Report|first=Lee|last=Doyle}}</ref><ref>[{{cite web=http://www.policychargingcontrol.com/1643-wind-river-s-launches-nfv-ecosystem-program-with-initial-five-industry-leaders Wind River Launches] NFV Ecosystem Program with Five Industry Leaders, PCC Mobile Broadband, Ray Sharma</ref>

However, to realize the anticipated benefits of virtualization, network equipment vendors are improving IT virtualization technology to incorporate carrier-grade attributes required to achieve [[high availability]], scalability, performance, and effective network management capabilities.<ref>'Carrier-Grade Reliability—A “[http://electronicdesign.com/communications/carrier-grade-reliability-must-have-nfv-success Must-Have]” for NFV Success', Electronic Design, Charlie Ashton, January 2015</ref> To minimize the total cost of ownership (TCO), carrier-grade features must be implemented as efficiently as possible. This requires that NFV solutions make efficient use of redundant resources to achieve five-nines availability (99.999%),<ref>'{{cite web|title=5 [must-have attributes of an NFV platform|url=http://www2.alcatel-lucent.com/techzine/5-must-attributes-nfv-platform/ must-have attributes] {{Webarchive|archive-url=https://web.archive.org/web/20150526044023/http://www2.alcatel-lucent.com/techzine/5-must-attributes-nfv-platform/ |archive-date=2015-05-26 }} of an NFV platform', |publisher=Techzine, Alcatel-Lucent, |first1=Andreas |last1=Lemke, |date=November 2014}}</ref> and of computing resource without compromising performance predictability.

The NFV platform is the foundation for achieving efficient carrier-grade NFV solutions.<ref>'Why Service Providers

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[[ETSI]] has already indicated that an important part of controlling the NFV environment be done through automation and orchestration. There is a separate stream MANO within NFV outlining how flexibility should be controlled.<ref>[http://network-functions-virtualization.com/mano.html Mano at network-functions-virtualization.com ]</ref>

ETSI delivers a full set of standards '''enabling an open ecosystem''' where Virtualized Network Functions (VNFs) can be interoperable with independently developed management and orchestration systems, and where the components of a management and orchestration system are themselves interoperable. This includes a set of [[Representational state transfer|Restful API]] specifications<ref>{{Cite journal|last=Chatras|first=B.|date=December 2018|title=On the Standardization of NFV Management and Orchestration APIs|journal= IEEE Communications Standards Magazine|volume=2|issue=4|pages=66–71|doi=10.1109/MCOMSTD.2018.1800032|s2cid=59620488|issn=2471-2825}}</ref> as well as the specifications of a packaging format for delivering VNFs to service providers and of the deployment templates to be packaged with the software images to enable managing the lifecycle of VNFs. Deployment templates can be based on [[OASIS TOSCA|TOSCA]] or [[YANG]].<ref>{{Cite web|url=https://www.etsi.org/newsroom/press-releases/1540-2019-01-etsi-releases-a-standard-for-nfv-deployment-templates|title=ETSI - ETSI releases a standard for NFV Deployment Templates|last=ETSI COMS TEAM|website=ETSI|access-date=2019-07-09}}</ref><ref>{{Cite web|url=https://www.etsi.org/newsroom/blogs/entry/sol006-nfv-descriptors-based-on-yang-specification|title=Technology blogs, NFV, MEC, NGP, ZSM, ENI - SOL006 – NFV descriptors based on YANG Specification|website=www.etsi.org|access-date=2019-07-09}}</ref>

An [[OpenAPI Specification|OpenAPI]] (a.k.a. Swagger) representation of the API specifications is available on the ETSI forge [https://forge.etsi.org/gitlab/nfv server], along with TOSCA and YANG definition files to be used when creating deployment templates.