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Networking professionals sometimes use the terms virtual network functions, or VNF, and network functions virtualization, or NFV, interchangeably, which can be a source of confusion. However, if we refer to the NFV specifications the European Telecommunications Standards Institute, or ETSI, sets forth, it becomes clear the two acronyms have related but distinct meanings.
First, what is a network function? The term typically refers to some component of a network infrastructure that provides a well-defined functional behavior, such as intrusion detection, intrusion prevention or routing.
Historically, we have deployed such network functions as physical appliances, where software is tightly coupled with specific, proprietary hardware. These physical network functions need to be manually installed into the network, creating operational challenges and preventing rapid deployment of new network functions.
A VNF, on the other hand, refers to the implementation of a network function using software that is decoupled from the underlying hardware. This can lead to more agile networks, with significant Opex and Capex savings.
In contrast, NFV typically refers to the overarching principle or concept of running software-defined network functions, independent of any specific hardware platform, as well as to a formal network virtualization initiative led by some of the world's biggest telecommunications network operators. In conjunction with ETSI, these companies aim to create and standardize an overarching, comprehensive NFV framework, a high-level illustration of which appears below. Notice the diagram highlights VNFs that are deployed on top of NFV infrastructure, which may span more than one physical location.
To summarize, NFV is an overarching concept, while a VNF is building block within ETSI's current NFV framework.
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Designing a virtualized infrastructure
Carriers fine-tune VNF menu
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