Networking or SDN, has had more than its fair share of hype with a plethora of perspectives, use cases, views on adoption rates and explanations about what SDN actually comprises. As someone who has been evangelising the merits of the software defined paradigm and network virtualisation since 2010, here is my own take on it.  

Let’s start with use cases, because this highlights a key gap in understanding the value SDN can bring to the data centre and potentially, the Wide Area Network (WAN). When companies look at SDN, they are looking primarily at an SDN infrastructure. They want the silver bullet that will allow them to automate, or make more elastic, many of their day-to-day operational challenges. The problem is that SDN infrastructure on its own doesn’t deliver on this objective.

The SDN infrastructure is simply the mechanism – often referred to as the control plane – by which network application services accomplish this objective. For those interested in how to gain operational efficiency through elastic scaling, agile provisioning, disaggregation and just-in-time deployment of application centric network services – while also automating network resilience – then, intelligent network application services integrated with the SDN infrastructure are the key to reaching those goals.

Take the example of KEMP’s SDN Adaptive technology, which currently runs within the load balancer. It communicates with the SDN controller to collect information about the health of the switch infrastructure. When there are issues, which would impact the quality of experience for users trying to access hosted applications it supports, traffic steering requests are used to move flows around the hotspot. This is important, because today’s controllers use a ‘set and forget’ approach to flow programming.

Another example of application optimisation in SDN is the addition of Quality of Service (QoS) functionality. Here, the Application Deliver Controller (ADC) receives the flow request requiring a specific level of priority. For example, if it is a video request, the ADC will set the QoS marking on the forward path through the switch infrastructure toward the video service. At the same time, the ADC calls the controller and requests that it set the response priority out of the server at the same level, so the user gets bi-directional QoS for their video. The result is a clean, jitter-free video stream, all set dynamically with no flow-by-flow manual requirements.

Levels Of Adoption

Adoption rates of SDN are a real hot topic. Many ‘naysayers’ are downplaying the future of SDN, while others are more passively observing the uptake and asking why it hasn’t happened more quickly. The reality is, SDN is for real and is being adopted in Proof of Concept (PoC) projects at a significant rate. The reason SDN isn’t deployed as broadly in production as we would like to see is two-fold.

Firstly, the use cases are not yet understood and companies are not yet looking at scenarios where the network application services can provide. Secondly and equally relevant, is that the adoption of true SDN infrastructure and not the vendor specific ACI or NSX type deployment, requires the use of Openflow or, in some cases, alternative South-bound interfaces to the switches. This means the environment needs to have Openflow support in the switches.

With this being a requirement, it is tough for IT to argue the CAPEX benefits of SDN deployment initially. But this is only a short term challenge as many data centres go through regular infrastructure refreshes.

Greenfield infrastructures are also being rolled out and one of the great things about SDN is that it can run simultaneously with traditional networks along-side. I am predicting that SDN infrastructure adoption will accelerate throughout 2016, providing the means for IT and business unit leaders to explore the benefits of application level use cases around operational efficiency and resilience, such as network services automation, rapid time-to-service, cloud integration and hybrid automation services. There will also be many other as-of-now, undiscovered benefits of this emerging technology.

There are many companies developing network services applications for SDN. SDN brings the value of network virtualisation to a whole new level by enabling those services to influence the infrastructure directly and dynamically on behalf of the hosted applications and their users. No doubt, the SDN debate will go on but we are at a tipping point and this time next year there will be less toe dipping and more diving in.