In contrast to classic approaches that employ proprietary hardware platforms, NFV set out to describe how service offerings may be delivered from in infrastructure comprising purely Virtualized Network Functions (VNFs). Initially, this could be realized by employing IT-like hardware virtualization techniques, deploying software within virtual machines running on commercial off the shelf, x86-based server hardware.
Early contributions to the NFV initiative described how significant cost savings could be realized not only by the decoupling of software from vendor-specific hardware but by leveraging the automation attributes of existing virtualization techniques to simplify the deployment and scaling of network components within standardized NFV infrastructure.
The NFV reference architecture diagram from ETSI specifications documents circa 2013
In order to realize the level of savings in operational expenditure required to support such a dramatic change in business models, the NFV community quickly endorsed the application of Software Defined Networking (SDN) techniques to automate end-to-end service creation through processes such as Service Function Chaining (SFC).
Much of the effort, since, has focused around this management and orchestration (MANO) layer, with many other industry initiatives, alliances and partnerships forming around the desire to guarantee interworking where no specific standards are applicable or currently exist. Most recently, it has become apparent that porting software from legacy network functions onto hardware-based virtual machines will not enable network operators to fully realized the benefit of building a private cloud for deploying VNFs. Moreover, such VNFs cannot leverage public cloud infrastructures for rapid capacity bursts or redundancy. Consequently, the NFV community is now focusing on building VNFs which are cloud native in their design and deployment methodologies.
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