What does SDN mean? Well, for starters, it simply means more control over the hardware. Normally it’s the router in a setup that redirects traffic by looking at the packets. It does so, with packet translation technology and automatic self routing. With SDN, the router which normally is a hardware device will relinquish control to software.
What this essentially means is that the entire network experience right from receiving to sending packets of information will be controlled by software. The software will provide full management control to the network. Any administrator would get complete access to the integrities of the network.
For Cloud computing setup’s this is a boon. As you can load balance your servers very well. For hardware companies like Cisco, this could be a threat. But there is a way around it. An emerging standard called ‘OpenFlow’ is making inroads into SDN land. Although the exact details are being chalked out, this holds great promise for SDN in the future.
As software-defined networking gains traction, vendors and enterprises will adopt a three-tiered architecture, which develops OpenFlow-based controllers. The architecture’s first tier will involve the physical network equipment, including Ethernet switches and routers. The middle tier consists of the controllers that initiate and terminate traffic leveraging a library of enterprise-wide information about capacity and demand from the networking gear that shuttles the traffic. The top tier will involve applications to direct security, management and other specific functions through the controller.
These controller-based applications will serve the same roles that physical appliances play in the network today. For example, network architects who are building software-defined networks could deploy applications like a virtual load balancer, a virtualintrusion detection system (IDS), or a virtual firewall on a controller. The application could tap into information the controller possesses about traffic patterns, application data and capacity. If the IDS application recognizes malware traffic based on the flows tracked by a controller, it could automatically isolate those packets before they infect the network.
The possibilities are endless. While everyone seems to be pinning their hopes on the OpenFlow standard, software has already started appearing over the horizon. What folks are waiting for is confirmation of OpenFlow use cases, which according to me is a matter of time.