What’s network functions virtualization (NFV) and how does it work?

SDxCentral notes that NFV is defined by “the decoupling of network functions from proprietary hardware appliances” and using these functions as virtual machines (VMs).  A network architecture concept, NFV uses IT virtualization technology to virtualize networks into building blocks that can connect or link up to produce communication services.

Techopedia defines NFV as a procedure that “increases and improves network function [and] managing networks”. NFV, which is sometimes referred to as network function virtualization, functions by changing how architect networks deliver network services, chaining together disparate classes of network nodes. It then creates a form of communication or makes certain information widely available to specific or general users.

It’s important to note that although networks are meant to be virtualized using NFV, network functions aren’t meant to be virtualized. Firewalls, traffic control and virtual routing are three of the most common virtual network functions (VNFs). Other functions include working as an alternative to load balancers and routers.


NFV architecture

The European Telecommunications Standards Institute (ETSI) proposed the NFV architecture, which has helped to define the NFV implementation standards. In pursuit of improved stability and interoperability, these NFV architecture components were modelled on the implementation standards.

The following are the components of the NFV architecture:

  • VNFs. Software apps that generate network functions, including file sharing, Internet Protocol (IP) configuration and directory services
  • Network functions virtualization Infrastructure (NFVI). Made up of the following infrastructure components:
    • Compute
    • Storage
    • Networking

These components work from a platform to support software that’s needed for running networking apps.

  • Management, automation and network orchestration (MANO). Supports the framework for provisioning new VNFs and controlling the NFV infrastructure

Why use NFV for your business?

As of 2018, most personal computers and mobile devices are constructed around the x86 family of instruction set architectures. Virtualized networking components (VNCs) are used by NFV to bolster a hardware-independent infrastructure. Virtualized resources, including the resources used for computing, storage and network functions, can be placed on x86 servers and similar types of commercial off-the-shelf (COTS) hardware.

Also, the data plane and control plane within the data center and outside networks can be virtualized with NFV.


What are the challenges of using NFV?

Three technology components make up the core challenges around using NFV. They consist of the following:

  1. The NFV manager (NFVM)
  2. VNFs
  3. The NFVI

These three components are so incredibly tightly bound together that they result in added complexity and difficulty when deploying NFV at scale.

During the second quarter of 2019, Lean NFV worked to resolve this issue and developed a different method for the NFV architecture. In its white paper, Accelerating Innovation with Lean NFV, the authors argue the issues that hinder NFV include when the existing computational infrastructure is integrated with the NFV manager and coordination is required between various components of the NFV manager.

The authors note that the three points of integration need to be simplified for innovation to be freely fostered on other elements of the NFV design.

There are different organizations currently competing against one another and working towards the goal of standardizing the NFV technology components. This lack of uniformity is one of the reasons for the complexity in these components. There has been no individual approach that’s worked for the whole industry and no standard that has been adopted or otherwise invested in.


What are the benefits of NFV?

There are plenty of reasons for organizations to use NFV, including the following benefits:

  • Better communication
  • Reduced costs
  • Improved flexibility and accelerated time to market for new products and updates
  • Improved scalability and resource management
  • Reduced vendor lock-in

Better communication and information accessibility

In addition to managing networks, NFV improves network function by transforming how the network architects generate network services. This process is performed by using an architectural and creatively designed method to link together different network nodes to produce a communication channel that can provide freely accessible information to users.

Reduced costs

Often used to great effect for decoupling network services, NFV can also be used as an alternative for routers, firewalls and load balancers. One of the appeals of NFV over routers, firewalls and load balancers is that it doesn’t require network proprietors to purchase dedicated hardware devices to perform their work or generate service chains or groups. This benefit helps to reduce the cost of operating expenses and allows work to be performed with fewer potential operating issues.

Improved scalability

Because VMs have virtualized services, they can receive portions of the virtual resources on x86 servers, allowing multiple VMs to run from a single server and better scale, based on the remaining resources. This advantage helps direct unused resources to where they’re needed and boosts efficiency for data centers with virtualized infrastructures.

NFV allows networks the ability to quickly and easily scale their resources based off of incoming traffic and resource requirements. And software-defined networking (SDN) software lets VMs automatically scale up or down.

Better resource management

Once a data center or similar infrastructure is virtualized, it can do more with fewer resources because a single server can run different VNFs simultaneously to produce the same amount of work. It allows for an increased workload capacity while reducing the data center footprint, power consumption and cooling needs.

Flexibility and accelerated time to market

NFV helps organizations update their infrastructure software when network demands change, starkly reducing the need for physical updates. As business requirements change and new market opportunities open, NFV helps organizations quickly adapt. Because a network’s infrastructure can be altered to better support a new product, the time-to-market period can be shortened.

Reduced vendor lock-in

The largest benefit of running VNFs on COTS hardware is that organizations aren’t chained to proprietary, fixed-function boxes that take truck rolls and lots of time and labor for deployment and configuration.


What’s the difference between NFV and SDN?

In the article “SDN vs. NFV: What’s the difference?” the author notes that the principle “similarity between [SDN] and [NFV] is that they both use network abstraction”. The author notes that “SDN seeks to separate network forwarding functions while NFV [abstracts them] and other network functions from the hardware [that they’re running on]”.

Both NFV and SDN rely on virtualization for network design and infrastructure abstraction in software, and then post-abstraction implementation using the underlying software on hardware devices and platforms.

NFV and SDN are often used in tandem with one another and they do share some similarities. They are different in how they separate functions and abstract resources. Both NFV and SDN use commodity hardware and help create flexible, programable and resource-efficient network architecture.

SDN helps create a network that can be centrally managed and programmed by separating network forwarding functions. NFV shifts network functions from hardware to software, bolstering SDN with infrastructure that SDN software can run on.

After SDN runs from NFV infrastructure, it forwards data packets from a single network device to a different network device. While this process occurs, the SDN’s networking control functions for applications, routing and policy definitions run from a VM on the network. NFV provides general networking functions and SDN orchestrates networking functions for specific purposes, allowing behavior and configuration to be programmatically modified and defined.

NFV and SDN take differing approaches when it comes to functions and resource abstractions.  SDN abstracts switches, routers and other physical networking resources, then shifts the decision-making onto a virtual network (VN) control plane. The control plane then chooses where to send the traffic and the hardware directs and handles the traffic. The NFV approach strives to virtualizes all physical networking resources under a hypervisor. This approach helps promote network growth without incorporating additional devices.

NFV and SDN can be used together, depending on what you want to accomplish, and both use commodity hardware. With NFV and SDN, you can create a network architecture that’s more flexible and programmable and uses resources efficiently.


NFV, SDN, and API

NFV is network component virtualization and SDN is network architecture that puts automation and programmability into the network by decoupling network control and forward functions. When NFV virtualizes all the infrastructure in a network, SDN centralizes the network’s control, creating a network that uses software to construct, control and manage it.

An SDN controller, northbound application programming interfaces (APIs) and southbound APIs are often included with an SDN. With the controller, network administrators can see the network and decide on the policies and behaviors of the adjacent infrastructure. Northbound APIs are used by applications and services to inform the controller of what resources it needs. Southbound APIs help the network run smoothly by processing information about the network’s state from the infrastructure and forwarding it to the controller.

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