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GCN : September 2015
bilities rather than looking at specific technology first. Security is another reason the De- fense Department and other agencies should be considering SDN. Typically, we think of the SDN controller as push- ing policy and control messages “down” to the network elements. However, the SDN controller’s ability to use two-way communications between controller/ application and network elements can play a huge role in security. Agencies can improve threat detection by using the SDN controller to automatically alert the network to suspicious events and direct further investigation. THE FUTURE OF SDN The hype around SDN is growing in government and prompting many CIOs and CTOs to educate themselves on the technology’s key concepts and benefits. It is important that agencies under- stand SDN capabilities and the options available to them before diving into the pool headfirst. By taking advantage of SDN solu- tions that integrate with existing hard- ware and open-standard distributed routing protocols, agencies can ease SDN elements into their infrastructure and operations teams. SDN is not easy. It can leave even the smartest minds in government IT confused and searching for answers. But there is no doubt that it can offer tremendous value for agencies as they seek to simplify and improve network operations. • — Mike Younkers is senior director of systems engineering for Cisco’s U.S . Federal team. How SDN works We break down how one of the hottest new trends in IT today functions and how it can be used to benefit your network. GCN SEPTEMBER 2015 • GCN.COM 27 Helps improve user experience Increases agility Reduces IT complexity Lowers operational costs as budgets decline Offers the flexibility/ scalability agencies need to innovate/ enhance service offerings for citizens PROS OF USING SDN 1 THE CONTROL PLANE VS. THE DATA PLANE A network does two things: sets up connections based on a set of criteria to identify the shortest, quickest or most secure path and then moves data across those connections. Connections are set up on the control plane, and data is moved on the data plane. 2 LAYERING IN THE NETWORK PLANES Layers are built into the data plane, which make it simple, fast and efficient to change something in one layer without affecting any other layers in the same plane. The control plane has no similar layering. Instead, numerous protocols determine how to set up connections. More protocols have been added over the years, creating greater complexity. 3 THE SDN SOLUTION With the planes split, good computer science principles can be applied to the control plane to solve similar problems once, then reuse those solutions to reduce complexity without disturbing anything in the data plane. 0915gcn_026-027.indd 27 9/2/15 2:15 PM