SDN or Software-Defined Networks has slowly been gaining momentum in the ICT world over the past few years. Whilst IDC points out that the SDN market is still early, with worldwide sales at US$ 360 million, the number is expected to grow significantly and reach US$ 3.7 billion by 2016.
Research by Network Instruments highlighted that over the past four years, SDN has moved from having no place in an organisation in 2009, to planned deployment in 22% of organisations in 2014. Organisations worldwide are beginning to see the value that SDN brings in helping them achieve competitive advantage: from giving organisations a centralised and more gradual control of expansive networks, improved experiences with applications, to general availability, reliability and security.
What is SDN?
According to its original concept, SDN is an architecture that foresees the abstraction of network control and data plans. In SDN, the software responsible for defining a routing process, security policies, traffic engineering and data plans is separated from the data plane and the actual forwarding of the packet.
Network elements are responsible only for physical package routing, while all routing control is through software at what could be called a superior layer. The intelligent layer is decoupled from the physical network-forwarding layer, allowing the decision making process to be distributed across more systems, and enabling organisations to drive resources throughout the network at greater speed and with greater flexibility.
What drove the emergence of SDN?
Accelerated growth of mobile devices and social networks, along with the increasing adoption of cloud computing and the future use of intelligent sensors in various devices connecting virtually anything to the network (the so-called Internet of Things) have been the driving forces of SDN.
These forces have given people and businesses new opportunities to change the way they operate, with the network being at the core of these transformations. It acts as the binding agent, playing a critical role in enabling the new hyper-connected world of people, businesses and governments. Subsequently, current network architectures are under scrutiny.
Despite meeting the needs of most use-cases and delivering a robust and powerful performance, the physical scalability and operational effectiveness of current network architectures made the network an enabler and a risk. To overcome this, a new model for network architectures has been built.
It’s built on the bases of open standards, reduced complexities of scale, improved flexibility and faster resource deployment to deliver new efficiencies in operations, by driving up the network scale while driving down the cost of large or complex network deployments. This new network model is known as Software Defined Networks or SDN.
What can SDN bring?
SDN will create networks that are more flexible, more agile and less complex to operate:
- Networks where traffic policies can be quickly refined as business demand change, without having to individually configure switches and routers;
- Networks where applications can directly interact with network resources, allowing the infrastructure behavior to be automatically defined according to the applications needs; and
- Networks where virtualisation becomes as ubiquitous in the network as it is within the data centre, turning a relatively dumb ‘big pipe’ into an intelligent resource that can be applied and redeployed in an instant.
With SDN, the programmable network is born. Network elements are driven by Application Programming Interfaces (APIs) in their operating system, which will allow any applications, developed by a network vendor or a mobile application vendor, to interact with the system’s control plan, making traffic engineering decisions based on much more than just the physical devices mac, IP address or basic CoS or QoS metrics.
Ultimately, SDN provides the following benefits:
- Reduced complexities – In abstracting the control of the network from the physical infrastructure, the link between human control and network control is broken, thus removing complexities and improving response times to changes to the profile of the network.
- Centralised and gradual control – SDN brings expansive networks under central control. Decisions can be made and implemented centrally, to accurately direct resources and network profiles to make subtle changes that can deliver significant characteristic improvements.
- Improved application experience – One of the most celebrated characteristics of SDN is its ability to create intelligent responses to business demands. With simpler configuration and centralized control, network administrators can align infrastructures directly to an application or the end-users’ specific needs.
- Availability, reliability and security - SDN architectures significantly improve higher availability, reliability and security of network environments as they eliminate the need for manual interventions and individual device configurations.
In this new world, decisions could be made on information and business requirements as abstract as the SDN model itself; temperature, link cost, energy consumption or whatever needs to drive the network to drive the business.
To delve further into SDN, refer to our guide to SDN.