Exploring The Fundamentals of Software-Defined Networking

When it’s time to update from traditional networking to a software-defined networking approach, start by understanding the levels of control made possible through SDN.

By Michael Brenner

By Michael Brenner September 12, 2023

As business apps and data proliferate across different platforms and places, IT system administrators must see the entire network and control the flow of data quickly and easily. The adoption of software-defined networking is an answer to this increasingly common problem.

Understanding the fundamental workings and capabilities of SDN can empower IT decision-makers to effectively strategize on the adoption of SDN as a solution for navigating the complex future of enterprise data.

What Is Software-Defined Networking?

In a software-defined networking environment, administrators use specialized software or application programming interfaces to direct network traffic. This is in contrast to a traditional approach that relies on physical hardware devices such as routers and switches to complete the same tasks. 

With SDN, the control plane is abstracted from the complex underlying infrastructure. The result is a flexible and highly programmable solution that can react and scale to business demands without the need to maintain and deploy a vast fleet of physical network control devices.

The core features of an SDN environment are:

  • Centralization that allows for a holistic view of the entire environment from one location
  • Connectivity via streamlined network designs that provide consistent networking across various clouds from different vendors
  • Programmability network features and configurations, made even easier through the implementation of automation
  • Agility through software characteristics that allow for on-the-fly configuration adjustments as needed

The underlying features and capabilities unique to software-defined networking bring benefits to organizations beyond what is possible through traditional networking methods. A fundamental understanding of SDN makes it possible to utilize this method to the fullest.

The Benefits of Software-Defined Networking

For those still using traditional network control methods, it may not be readily apparent how a shift to a software-based approach can be worth the investment. In fact, there are several powerful and far-reaching benefits of adopting SDN.


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Software abstraction makes it easier to control any environment, particularly those utilizing tools from multiple vendors. It is no longer necessary to configure multiple vendor-specific devices. Instead, a single software control plane enables comprehensive application lifecycle management while granting control and visibility over the entire network.

Another benefit comes in the form of customizability. Network administrators can configure network services in real-time and even allocate virtual resources in immediate response to availability demands. This functionality is particularly useful for organizations looking to migrate some or all of their workloads to the cloud.

Maintaining strong network security is also more attainable through software-defined networking. Far-reaching visibility not only leads to greater control but also allows for stronger monitoring and threat-detection practices. System managers can seamlessly distribute security policies to the entire network and perform other crucial tasks from a central location.

Efficiency is perhaps the underlying concept of all the benefits provided through SDN. There is a strong argument for cost-efficiency in a method that improves resource and server utilization across the board, leading to lower TCO and greater return on investment. An emphasis on software can also boost operational efficiency and facilitate the growth of DevOps practices in any given production ecosystem.

How Software-Defined Networking Works

Software-defined networking is possible through the use of virtualization to decouple software from hardware. This is similar to the premise that fuels cloud computing technologies. By creating an abstract overlay on top of the complex networking infrastructure, administrators can make decisions via a simple control plane and application programming interfaces.

The control plane is one-half of the overall SDN architecture. It provides a simple point of access in the form of software that facilitates ease of management for the network administrator. 

The other half of the architecture is the data plane, which continues to exist in the physical hardware. This is where information travels from point to point based on instructions passed down from the control plane.


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There are three fundamental components that constitute a complete software-defined networking environment:

  • Applications: SDN components that rely on APIs to communicate requests and information to the controller layer
  • Controllers: Hub area of the SDN that collects data from applications to make informed decisions on where to route data packets
  • Networking devices: SDN endpoints that receive data from the controller about where to forward data processing tasks

SDN works due to the coordination of applications, controllers, and networking devices within the abstracted SDN software that serves as the underlying architecture along with the traditional hardware layer where data trafficking takes place.

The Differences Between SDN and Traditional Networking

It goes without saying that SDN is a software-based approach to networking, compared to a traditional approach that relies on hardware. What this means in practice is that operators in a software-defined networking environment can easily observe application characteristics within the network.

These characteristics include packet size and volume as well as latency and errors. Being able to monitor these types of attributes provides a level of insight into the network’s overall health that is not available through traditional networking means.

The software-based control plane is also much more flexible. It allows for on-demand configuration changes, rapid provisioning, and more cost-effective network capacity increases. IT managers can accomplish all of this from a single user interface and without additional hardware investments.


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SDN is able to clearly outshine legacy hardware-based networking in a number of use cases. For example, organizations looking to prioritize DevOps initiatives can utilize software-defined networking to automate updates, deployments, and other aspects of the application lifecycle while developers focus on creation.

Another common use of SDN is in improving security. The software-based networking approach makes it easy to create distributed firewall systems through virtualization and bolster the overall protection layer covering the network.

The security differences between SDN and traditional networking extend to visibility. It is difficult and often impossible to grasp the full scope of a traditional network from a single perspective, whereas doing so is a natural feature of SDN. This empowers a user to efficiently monitor the whole ecosystem and secure entire network pathways with ease.

The Role of Software-Defined Networking in Security

One of the key security functionalities enabled by software-defined networking is the ability to create different security sections in the network that become accessible based on clearance levels. Not only is this an inherent feature due to the high level of network visibility provided through SDN, but it is also a core tenet of a zero trust security strategy.

The zero trust philosophy in security dictates that all users, regardless of any bias or whether they are internal or external to the organization, must authenticate before gaining access to applications and data. SDN facilitates the implementation of this philosophy by allowing for easy deployment of security policies and seamless scalability.

SDN security differs from that of a traditional security network in that the software can define protections for each respective location in the network. Traditionally, there is only a single layer of protection that attempts to encompass the entire network.


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In its primer on network security architecture, Gartner explains that microsegmentation is another security benefit made possible through software-defined networking. Microsegmentation tools inhibit attackers who are already present in the target network, and it is possible to deploy these tools directly at the network level through SDN. 

A Software-Defined Networking Solution for a Complex Time

In an environment where every aspect of the cloud and its underlying infrastructure and networks are so complex, it does not have to be the case that the solutions are also complex. Rather, simple tools that hide the complexity are ideal for ensuring that IT teams can prioritize business and consumer-focused outcomes.

Nutanix Flow is an example of a software-defined networking solution with an emphasis on security. Flow acknowledges the inherent complexity of security in a multicloud setting but presents a simple solution that hardens a network against cyberthreats via built-in zero trust initiatives and automated regulatory compliance.

Adoption of SDN is a natural step forward for companies looking to extend their on-premises IT presence to the cloud through hyperconverged infrastructure. HCI utilizes a distributed software layer to converge the entire datacenter stack and to bridge the gap between clouds. The shared emphasis on taking a software-based approach makes SDN and HCI a natural and efficient fit.

Nutanix Cloud Infrastructure provides the foundation that businesses need to build a hybrid cloud complete with simple software-defined networking solutions and powerful hyperconvergence technology. Given that the fundamental concept behind SDN is to simplify and improve network control, it is something that many organizations cannot afford to not adopt as application data continues to proliferate exponentially in the future.

Learn more about Nutanix Flow Networking and Network Flow Security as well as how Nutanix Central can help manage Nutanix environments deployed on-prem or on public cloud.

Michael Brenner is a keynote speaker, author, and CEO of Marketing Insider Group. Michael has written hundreds of articles on sites such as Forbes, Entrepreneur Magazine, and The Guardian, and he speaks at dozens of leadership conferences each year covering topics such as marketing, leadership, technology, and business strategy. Follow him @BrennerMichael.

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