What is Network Functions Virtualization?

The telecom industry sometimes has a way of making even the smartest of us feel lost, confused, and occasionally even a little dumb.  Just when you’ve figured out the latest hot buttons in the industry buzz – cloud computing, OpenFlow, and software-defined networking (SDN) – along comes another new concept for you to get your head around. The latest new concept is called Network Functions Virtualization, or NFV, and it has rightfully taken its place in the industry conversation as another step toward creating a more agile, lower-cost network infrastructure.

What is Network Function Virtualization?

Network function virtualization (NFV) unlinks network services from proprietary hardware appliances, enabling them to run in virtual machines as software instead. Admins can virtualize standard compute, storage, and network function resources and place them on commercial off-the-shelf (COTS) hardware such as x86 servers. Giving available x86 server resources to the VMs keeps network services independent of hardware.

In this way, network function virtualization allows multiple virtualized network functions (VNFs) to run on just one server and scale to consume the free resources that remain. This virtualization of infrastructure also typically results in more efficient use of data center resources. Both outside networks and within the data center, NFV can also virtualize the control plane and data plane.

Components of Network Functions Virtualization

The NFV framework consists of three main components:

• Virtualized network functions (VNFs) are software implementations of network functions that can be deployed on a network functions virtualization infrastructure (NFVI).
• Network functions virtualization infrastructure (NFVI) is the totality of all hardware and software components that build the environment where VNFs are deployed. The NFV infrastructure can span several locations. The network providing connectivity between these locations is considered part of the NFV infrastructure.
• Network functions virtualization management and orchestration architectural framework (NFV-MANO Architectural Framework) is the collection of all functional blocks, data repositories used by these blocks, and reference points and interfaces through which these functional blocks exchange information to manage and orchestrate NFVI and VNFs.

Why Network Functions Virtualization?

NFV allows for the separation of communication services from dedicated hardware, such as routers and firewalls. This separation means network operations can provide new services dynamically and without installing new hardware. Deploying network components with network functions virtualization takes hours instead of months like with traditional networking. Also, the virtualized services can run on less expensive, generic servers instead of proprietary hardware.

Additional reasons to use network functions virtualization include:

• Pay-as-you-go: Pay-as-you-go NFV models can reduce costs because businesses pay only for what they need.
• Fewer appliances: Because NFV runs on virtual machines instead of physical machines, fewer appliances are necessary and operational costs are lower.
• Scalability: Scaling the network architecture with virtual machines is faster and easier, and it does not require purchasing additional hardware.

What are the advantages of NFV?

NFV reduces the need for dedicated hardware to deploy and manage networks by offloading network functions into software that can run on industry-standard hardware and can be managed from anywhere within the operator’s network.

Separating network functions from hardware yields numerous benefits for the network operator, which include:

• Reduced space needed for network hardware
• Reduce network power consumption
• Reduced network maintenance costs
• Easier network upgrades
• Longer life cycles for network hardware
• Reduced maintenance and hardware costs

NFV Applications

NFV is applicable across a broad scope of network functions, including mobile networks. Some common applications of network function virtualization include:

• Content delivery networks (CDN), including content delivery services, such as video streaming
• Evolved packet core (EPC)
• IP multimedia subsystem (IMS)
• Network monitoring
• Network slicing
• Load balancers
• Web Application Firewalls
• Security functions, including intrusion detection and prevention systems, firewalls, and NAT
• Session border control (SBC)
• Software-defined branch and SD-WAN
• Virtual customer premises equipment (vCPE)

Software-defined networking (SDN) and NFV

NFV and SDN are not dependent on each other, but they do have similarities. Both rely on virtualization and use network abstraction, but how they separate functions and abstract resources is different.

SDN separates network forwarding functions from network control functions intending to create a network that is centrally manageable and programmable. NFV abstracts network functions from hardware. NFV supports SDN by providing the infrastructure on which SDN software can run.

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 is more flexible, programmable, and uses resources efficiently.