Network function virtualization: Difference between revisions

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==Relationship to SDN==

InNetwork essence,Functions softwareVirtualisation is highly complementary to [[Software-definedDefined networkingNetworking]] (SDN). In essence, 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 high-level APIs and novel management paradigms, such as Intent-based networking. 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.

SDN, or [[software-defined networking]], is a concept related to NFV, but they refer to different domains.<ref name = Stalling2016>{{cite journal|last=William|first=Stalling|title= Foundations of Modern Networking: SDN, NFV, QoE, IoT, and Cloud |journal= Pearson Education |date= 2016 }}</ref>

Network functions virtualization (NFV) and Deep Packet Inspection (DPI) could efficiently complement the SDN functions.<ref>{{cite journal|last=Rowayda|first=A. Sadek|title= An Agile Internet of Things (IoT) based Software Defined Network (SDN) Architecture |journal= Egyptian Computer Science Journal |date=May 2018 }}</ref>

Thus, NFV is not dependent on SDN or SDN concepts, but NFV and SDN can cooperate to enhance the management of a NFV infrastructure and to create a more dynamic network environment. 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 Network Services (NS), composed of different type of Network Functions (NF), such as Physical Network Functions (PNF) and VNFs, and placed between different geo-located NFV infrastructures, 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>

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.

An NFV infrastructuresystem needs a central orchestration and management system that takes operator requests associated with an NS or a VNF, translates them into the appropriate processing, storage and network configuration needed to bring the NS or VNF into operation. Once in operation, the VNF and the networks it is connected to 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>

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>

All thesenetwork control functions in an NFV infrastructure can be accomplished using SDN concepts and NFV could be considered one of the primary SDN use cases in service provider environments. For example, within each NFV infrastructure site, a VIM could rely upon an SDN controller to setup and configure the overlay networks interconnecting (e.g. VXLAN) the VNFs and PNFs composing an NS. The SDN controller would then configure the NFV infrastructure switches and routers, as well as the network gateways, as needed. Similarly, a Wide Area Infrastructure Manager (WIM) could rely upon an SDN controller to setup overlay networks to interconnect NSs that are deployed to different geo-located NFV infrastructures. It is also apparent that many SDN use-cases could incorporate concepts introduced in the NFV initiative. Examples include where the centralized controller is controlling a distributed forwarding function that could in fact be also virtualized on existing processing or routing equipment.

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>

All these functions can be accomplished using SDN concepts and NFV could be considered one of the primary SDN use cases in service provider environments. It is also apparent that many SDN use-cases could incorporate concepts introduced in the NFV initiative. Examples include where the centralized controller is controlling a distributed forwarding function that could in fact be also virtualized on existing processing or routing equipment.

==Industry impact==