What is SDN?

Software-Defined Networking

Software-Defined Networking (SDN) is a new perspective on the design, implementation and management of networks. SDN is designed to merge the network into the age of the cloud. This most recent evolution of the modern network promises to make the network more elastic, agile, and dynamic, yet to keep pace with today’s rapidly changing business demands.

How does it work?

SDN is an approach to network virtualisation that seeks to optimise network resources and quickly adapt networks to changing business needs, applications, and traffic. It works by separating the network’s control plane and the data plane, creating a software-programmable infrastructure that is distinct from physical devices.

With SDN, the functions of network orchestration, management, analytics, and automation become the job of SDN controllers. Because these controllers are not networking devices, they can take advantage of the scale, performance, and availability of modern cloud computing and storage resources. Increasingly, SDN controllers are built on open platforms, using open standards and open APIs, enabling them to orchestrate, manage, and control network equipment from different vendors.

Benefits of SDN

SDN delivers a wide array of business benefits. Separation of the control and transport layers increases flexibility and accelerates time-to-market for new applications. The ability to respond more swiftly to issues and outages improves network availability. And programmability makes it easier for IT organisations to automate network functions, reducing operating costs.

SDN allows network administrators to manage network services through the abstraction of lower-level functionality. This is done by splitting the system into two. One part makes decisions about where traffic is sent (the control plane). The other part forwards traffic to the selected destination (the data plane).

SDN dovetails with another technology, Network Functions Virtualisation (NFV). NFV offers the ability to virtualise appliance-based network functions such as firewalls, load balancers, and WAN accelerators. The centralised control that SDN provides can efficiently manage and orchestrate virtual network functions that are enabled by NFV.