LAS VEGAS—Discussions about software-defined networking at Interop last week ranged from “SDN rules!" to "What is SDN again?" More than once the answer to the question about what separates one SDN solution from another was, "you tell me."
It's odd that software-defined networking has been around for so long (at least in Internet time), yet it is still being defined, so to speak. It's been four years since OpenFlow, the first enabler of SDN, was the talk of the 2011 Interop.
It's been two years since SDN proponents started to defend themselves against over-hyping the topic. The potential was there. People were asking about it, but where was it all heading?
Skip to today and the hype is still there, but there’s much more substance to it. There isn't a major networking vendor that isn't offering or enabling software-defined networking products, but now it feels as if we are back at the beginning. That's because users and vendors alike are just starting to realize the true impact of SDN technology and the changes it will impose on businesses and IT departments.
One big change has already happened. SDN software and SDN-enabled switches are here and maturing, enabling separation of the control and data layers of a network, creating an environment of centralized management and programming. There are several implications for this new paradigm.
The application is now the center of the networking world, not the switches or the routers or the cabling in and of themselves. Along with the applications developers and their APIs are closer to the core of the networking world.
"Networks only exist to support applications," IDC analyst Brad Casemore said at IDC's Interop breakfast briefing last week. "SDN rose out of the need to be able to develop and manage applications for the cloud in rapidly changing business environments.
“You don't develop application architectures for the fun of it. If your applications aren't going to change, you really don't need to change your network. When your workload changes, you really do need to look at your network and make sure your network can support those applications,” he said.
As a result, developers and administrators can set networking policies, and invoke bandwidth and other networking needs on demand, turning them off when the application is closed. This saves time compared to provisioning hardware manually, and it saves needless traffic on the network, improving performance overall.
Policy is everything. This is another line I heard several times at the conference. Applications are developed with networking functions defined by policies. Set it and forget it. There's no need to reconfigure hardware manually.