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GCN : September 2015
techincontext NETWORKING Software-defined networking is a major trend in the IT indus- try, as big as cloud computing and data analytics. And as with many mega-trends, there exists a fair amount of confusion and rhetoric on the topic, which is dangerous for IT decision- makers inside and outside government. Nevertheless, SDN is already help- ing improve operations at government agencies. To understand its potential, it is important to have some context on its origins, its current use and its prospects for the future. WHAT IS THE PURPOSE OF SDN? Every new technology product or ap- proach starts with the need to over- come a challenge. The impetus for SDN was the incredible complexity that ex- ists in designing, deploying and main- taining modern-day networks. Networks do two things: They set up connections based on a set of criteria to identify the shortest, quickest or most secure path (the control plane) and then they move data across those con- nections (the data plane). The funda- mental premise of SDN is to separate the decision-making happening in the control plane from the execution of those decisions in the data plane. When the network frameworks were originally established, considerable ef- fort was put into building layers into the data plane. Those layers make it simple, fast and efficient to change something in one layer without affect- ing any other layers in the same plane. For example, when a faster physi- cal technology comes along — think switching from copper to fiber — an upgrade can be done without affecting the higher layers. Unfortunately, there is no similar lay- ering within a network’s control plane. Instead, numerous protocols determine how to set up connections. Over the years, more and more protocols have been added, creating ever greater com- plexity. By splitting the control plane from the data plane, the complexity of the control plane can be addressed without disturbing what already works well in the data plane. Once the split occurs, we can apply good computer science principles in the control plane to solve similar prob- lems once and then reuse that solution to reduce complexity. That’s what de- fines SDN: Its fundamental purpose is to simplify the design, deployment and operation of networks by bringing rigor and structure to the control plane. WHY DOES SDN MATTER FOR GOVERNMENT? SDN solutions can help government CIOs address key challenges they are facing today. It can help improve user experience, increase agility, reduce IT complexity and lower operational costs as budgets decline. The new models of- fer the flexibility and scalability agen- cies need to innovate and enhance ser- vice offerings for citizens. Those features are attractive for agencies seeking to improve their net- work operations. For instance, the Defense Informa- tion Systems Agency issued a request for information about SDN earlier this year to gain a better understanding of how experts in the network and cloud industries are innovating and using the new capabilities. The smartest thing DISA did was openly pose three challenges their IT department faces and ask how industry would solve each with SDN. That is the right approach because it focuses on solving real problems with SDN capa- To understand the potential of software-defined networking, it is important to know where it came from and what it can do Why SDN matters: The case for reducing complexity BY MIKE YOUNKERS 26 GCN SEPTEMBER 2015 • GCN.COM SDN is not easy. But there is no doubt that it can offer tremendous value for agencies as they seek to simplify and improve network operations. 0915gcn_026-027.indd 26 9/2/15 9:16 AM