Network function virtualization Basics

Here we are going to talk about NFV or so called Network function virtualization which is a network architecture concept that uses the technologies of IT virtualization to virtualize entire classes of network node functions into building blocks that may connect, or chain together, to create communication services.

Network Function Virtualization can be summed up by the statement that: "Due to recent network focused advancements in PC hardware, Any service able to be delivered on proprietary, application specific hardware should be able to be done on a virtual machine". Essentially: Routers, Firewalls, Load Balancers and other network devices all running virtualized on commodity hardware.

Fig 1.1- Introduction to NFV

The concept originated from service providers who were looking to accelerate the deployment of new network services to support their revenue and growth objectives. The constraints of hardware-based appliances led them to applying standard IT virtualization technologies to their networks.

NFV relies upon, but differs from, traditional server-virtualization techniques, such as those used in enterprise IT. A virtualized network function, or VNF, may consist of one or more virtual machines running different software and processes, on top of standard high-volume servers, switches and storage, or even cloud computing infrastructure, instead of having custom hardware appliances for each network function.

What Makes NFV Different
While PC-based network devices have been available since the '80s, they were generally used by small companies and networking enthusiasts who didn't or couldn't afford to buy a commercial-based solution.

In the last few years many drivers have brought PC-based networking devices back into the limelight, including: Ethernet as the last mile, better network interface cards, and Intel's focus on networking processing in its last few generation of chips.

Today many vendors are producing PC-based network devices. Advancements in packet handling within Intel's processors, allowing processor cores to be re-programmed into network processors, allow PC-based network devices to push 10's or even 100's of Gbps.

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 function virtualization infrastructure (NFVI).
  • Network function 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 as 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 for the purpose of managing and orchestrating NFVI and VNFs.

Values of NFV
Some of the values to the NFV concept are speed, agility, and cost reduction. By centralizing designs around commodity server hardware, network operators can:
  • Virtualization allows providers to allocate only the necessary resources needed by each feature/function.
  • Avoiding designs involving one-off installs of appliances that have different power, cooling and space needs simplifies planning
  • Deploy network functions without having to send engineers to each site;
  • Truck Rolls” are costly both from a time and money standpoint.
  • Achieve Reductions in OpEX and Capex; and,
  • Achieve Reduction of system complexity.