Network function virtualization (NFV) is becoming ever more popular working alongside software-defined networking (SDN) to transform businesses’ approach to virtualization by simplifying the work of an administrator while saving the user money.
What is network function virtualization (NFV)?
A simple way to understand NFV is that, with it, service providers and operators are able to abstract network services, including things such as load balancing, into a software that can run on basic servers.
According to the OpenStack Foundation, network-function virtualization “simply put, [is] a new way to define, create, and manage networks by replacing dedicated network appliances with software and automation.” Continuing the explanation, they explain that “it’s a continuation of the IT shift away from physical hardware that’s inflexible, proprietary, and expensive.”
Simply put, it's a new way to define, create, and manage networks by replacing dedicated network appliances with software and automation. — OpenStack Foundation
So, just as a shift occurred from physical servers to a larger amount of virtualized servers, the shift is now also happening on the level of physical networking infrastructure. With this new technology, a virtual network function (VNF) takes care of particular functions within the network, which could run on virtual machines, bare metal, or in containers, on top of the physical networking infrastructure.
Basically, network function virtualization is even more virtualization than before, including virtualizing “entire classes of network node functions into building blocks that may connect, or chain together, to create communication services.”
Essentially, the network services and applications that once ran on hardware appliances can be virtualized with NFV, potentially replacing many devices with more flexible software options that run on bare-metal servers. This would make way for a new kind of service chaining.
Why is it useful?
There are certain hardware problems and networking components that haven’t adapted as quickly as other types of technology have changed, including things like Big Data, and cloud computing.
It can be more difficult to deploy these physical components, integrate them with existing systems, have extended or equally long lifecycles, and more. To address this, network function virtualization infrastructures were created, attempting to address the issues by, according to the European Telecommunications Standards Institute (ETSI), “evolving standard IT virtualization technology to consolidate many network equipment types onto industry standard high volume servers, switches, and storage.”
They explain this working by “implementing network functions in software that can run on a range of industry standard server hardware, and that can be moved to, or instantiated in, various locations in the network as required, without the need to install new equipment.”
The great benefit of NFV implementation is being able to dynamically provision network components, applications, and services in a very short time frame, as opposed to weeks or even months.
With network function virtualization, firewalls or IDS/IPS can be set up in the same way as setting up a VM — with software on your computer. Network virtualization allows users to create tunnels through a network, and network function virtualization helps to place a service on those tunnels.
To make sure you understand network function virtualization, you first should grasp network virtualization. This functions by attempting to create logical segments in an existing network, similar to partitioning a hard drive, by separating the network into different portions at the flow level.
As referred to above, NV is essentially a tunnel that connects two domains in one existing network, rather than physically connecting them. This greatly assists administrators because, with NV, they no longer have to physically wire each new domain connection, particularly including virtual machines.
Rather than having to change any preexisting work, administrators can virtualize their infrastructure and make changes on top of an existing one.
NV is perfect for anyone who is using virtual machine technology already and helps users not have to reconfigure their network and move VMs independently of their existing infrastructure across different logical domains.
According to an article in Network World, “NFV uses best practices as base policies and configurations for different network elements. If you have a specific tunnel you’re punching through the infrastructure, you can add a firewall or IDS/IPS to just that tunnel.”
So, users are able to enable functions on certain, selected tunnels in the network, which allows them to build an abstraction on top of the network or tunnel, then build whichever virtual services best fit that environment. This helps to save both time and labor in comparison to manual provisioning.
It can also help users save money by buying specific functions for the particular tunnel they need it for rather than purchasing a large firewall or IDS/IPS boxes. This helps to reduce the initial capital investment while gaining operational benefits as well.
How NFV relates to SDN
Software-defined networks originated many years ago and help to create network abstractions. SDN physically separates the network control plane from the forwarding plane, and the control plane can control multiple devices.
The Open Networking Foundation (ONF), a user-driven organization dedicated to the promotion and adoption of SDN through open standards development, says that SDN is “an emerging architecture that is dynamic, manageable, cost-effective and adaptable, making it ideal for the high-bandwidth, dynamic nature of today’s applications.”
While it is certainly not necessary to pair NFV and SDN together as both can operate independent of each other, the partnership can be valuable. As explained very simply by the OpenDaylight project, “SDN enables users to program network layers, separating the data plane from the control plane while NFV allows for agile placement of networking services when and where they are needed.”
With so much customization, users can better increase network agility, service innovation, optimize their network resources, and enable better functioning virtual networks.
Essentially, both of these technologies have a similar approach. Both bring modularity, reusability, and interoperability to network management, complementing each other and helping control and configure the user’s network through software.
Using this combination, businesses can be better prepared to handle virtualized networks and employ a cloud-based or a hybrid cloud approach to their infrastructure.
As the combination isn’t a necessity, just using network function virtualization to switch from hardware-based to software-based solutions, the user’s network can be more automated and better functioning, while at the same time, costing less than before the switch.