SDN changes how a network is controlled; NFV changes how network functions are delivered. Software-defined networking (SDN) separates or abstracts network control from packet forwarding and makes control programmable. Network functions virtualization (NFV) runs functions such as firewalls and load balancers as software on virtualized infrastructure. They address different parts of networking and can be deployed independently, though they are often used together.
What is SDN?
Software-defined networking focuses on the network’s control plane: the logic that decides where traffic should go and how the network should behave. SDN separates that control from the forwarding plane, which handles the movement of packets, or otherwise abstracts control so it can be programmed through interfaces.
The Open Networking Foundation defines SDN as “the physical separation of the network control plane from the forwarding plane, and where a control plane controls several devices.” The IETF describes it as a programmable-network approach that supports separation of the control and forwarding planes through standardized interfaces in RFC 7426.
In practice, SDN can let an operator or software controller apply network-wide policies and direct traffic across multiple devices. The important distinction is what changes: the way forwarding behavior is controlled, not necessarily the underlying network functions.
PC Slower Than It Used to Be?
A free scan shows the junk files, broken settings and background clutter dragging Windows down - then fixes them in one click.Free scan · Windows 10 & 11Outdated Drivers Are Slowing You Down
One free scan finds every outdated or missing driver and matches the right update for your exact hardware.Free scan · exact hardware match#1 Best Overall
What is NFV?
Network functions virtualization focuses on how network services are implemented and deployed. Instead of relying only on dedicated appliances, an operator can run a network function—such as a firewall, router, or load balancer—as software on virtualized infrastructure. These software instances are commonly called virtual network functions.
NFV therefore concerns packaging, deploying, scaling, and managing functions on infrastructure. It does not, by itself, mean that the network’s control plane has been separated from its forwarding plane.
Rank #2
SDN vs. NFV: the key differences
| Comparison | SDN | NFV |
|---|---|---|
| Primary objective | Make network control and forwarding behavior programmable. | Implement network functions as software on virtualized infrastructure. |
| What it changes | How network devices are controlled and how traffic is directed. | How functions such as firewalls and load balancers are delivered. |
| Focus | Control-plane architecture, policy automation, and network-wide forwarding. | Function deployment and lifecycle management, scaling, and infrastructure use. |
| Typical operational outcome | Policies and paths can be programmed through a controller or interfaces. | Functions can run as software rather than only on purpose-built appliances. |
| Dependency | Can be used without NFV. | Can be used without SDN. |
Are SDN and NFV the same, or do they depend on each other?
No. SDN is not another name for network function virtualization: SDN is about control, while NFV is about implementing network functions in software on virtualized infrastructure. Neither technology requires the other.
ETSI states that NFV is “highly complementary” to SDN, but that the two are “mutually beneficial” rather than dependent on each other. An organization can use SDN with conventional network functions, or deploy virtualized network functions without an SDN architecture.
Rank #3
How SDN and NFV work together
In a combined deployment, NFV supplies software-based network functions and SDN can connect them and direct traffic through them. For example, an operator could run a firewall as a virtual network function, then use an SDN controller to program a path that sends selected traffic through that firewall before it reaches its destination.
ETSI materials address both the separation of SDN control and data functions and the placement of SDN controller functions in NFV infrastructure. This illustrates how the technologies can be integrated without making either one a prerequisite for the other.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Which one virtualizes the network?
NFV virtualizes network functions by implementing them as software on virtualized infrastructure. SDN makes network control programmable and separates or abstracts it from packet forwarding. So if the question is about turning a firewall or load balancer into software, that is NFV; if it is about centrally programming how traffic moves across the network, that is SDN.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
