The IT sector thrives on new trends and ‘game-changing’ technologies that drive innovation and improvement. The latest of these is software-defined networking (SDN).

In the wake of cloud computing and big data, SDN shows all the signs of being the next global trend to capture the imagination of CIOs and IT directors.

But is SDN merely another expensive addition to the data center, or is it really a disruptive new way to design network functions?

SDN allows different network elements to be managed by software through the separation of the network’s control and forwarding planes. Application programming interfaces bring network functions together under the control of specialized software, and changes to functionality no longer require physical adjustments to the infrastructure.

Functions such as load balancing, which once required dedicated devices, can now be performed by software running on generic server hardware. Applications requiring different configurations can be housed on the same systems without compatibility problems.

SDN simplifies physical network infrastructure and centralizes traffic management and application delivery. Administrators can quickly shift resources between areas of need as they deal with changing requirements.

While SDN is proving its worth to a number of organizations running large networks, it should not be viewed as something to adopt for its own sake. Rather, it is a necessary intermediate step that leads to a more foundational shift in IT – the software-defined data center (SDDC). As more individual hardware functions are transitioned to software, the natural progression is to virtualize the entire data center.

Software benefits
SDDC is the outcome of a familiar pattern to IT administrators that began with server virtualization. It is not just about multiplexing several workloads across general-purpose machines. Server virtualization offers an abstraction that is just right for the data center: provisioning, moving, snapshotting and rolling back are difficult in hardware but easy in software.

A ‘software-defined’ computer changes the operational model and streamlines management of workloads.

Desktop computers were next on the virtualization path. These have required manual installations of each software program. But applications have been streamed to users from internal servers or have been provided online as web-based applications. Now completely virtualized machines are commonplace, where even the underlying operating system resides on a server outside the user’s physical machine.

Now virtualization is coming to the network. Networks have been built with different types of limited virtualization for some time. Virtual LANs allow physically separated network segments to be grouped logically, and virtual switches permit a single server to mediate traffic between multiple virtual machines. Yet full-scale network virtualization is still in its infancy.

A fully virtualized network would bring together all the disparate segments, access control lists, forwarding and shaping policies and other elements into one portable software abstraction. This network will completely decouple the physical network from its virtual elements, with the scope of the control plane moving beyond an individual router or switch to be fully controlled by software. From the point of view of applications and operating systems, a virtual network functions in the same way as a physical network – no special configuration ‘above’ the network is necessary.

Virtualization has proven its worth and the SDDC represents a kind of full-scale virtualization that provides benefits in three crucial areas:

* Efficiency: In any complex machine, the more parts that are introduced the greater the chance one will break and bring down the system. SDDC allows the physical network to be streamlined, so resources can be shared evenly between applications.

* Security: High-profile attacks on businesses are on the rise, and as networks become more complicated there will be more points to attack. In an SDDC, network control is consolidated and centralized, which provides a greater degree of visibility into network behaviour and control over security.

* Cost-effectiveness: Constantly shrinking budgets mean IT administrators need to accomplish more with fewer resources. Generic ‘white box’ SDN-capable equipment is often much less expensive than traditional gear, reducing CAPEX and ongoing maintenance costs.

For many, a true SDDC will be some distance off. Nonetheless, organizations should adopt the right infrastructure elements early and begin to implement virtualization and SDN to help them progress toward a fully virtualized data center.

The SDDC will be a game-changing shift in IT, not just another buzzword. Those that have seen it coming and are prepared will realize benefits sooner.