“We are returning the network to the people who build it, deploy it, and use it. -Dan Pitt, executive director for the Open Networking Foundation

What is software-defined networking? The discussions around it at the NetEvents Americas event in Miami, FL this week attempted to hone in on that very question, including why it’s important for the progress of networking. One answer is that SDN is made up of specialized features and specialized hardware to the open interface for rapid innovation and is then ultimately taken to open applications. Another is that SDN is the notion of separating the controlling plane from the data plane – centralizing the network intelligence so specifying policies in a “humanized” language is possible. SDN aims to create network abstraction to make this possible.

The problem that SDN attempts to address is real, according to Dan Pitt, executive director for the Open Networking Foundation. SDN aims to address the “pain points” in networking, and as a potential solution, it uses an approach to reduce complexity by adding abstraction.

In a session titled “The SDN Revolution – Empowering the People,” this week at NetEvents Americas in Miami, FL, Pitt explored why we need SDN. Ultimately, service providers want to be able to “control their futures,” he said. “They want the network to do what they want it to do and when they want it to do it. Our market is being driven by the hyperscale data center operators such as Google. What they’ve taken on early will permeate all the other public and private data center operators. Networking is linked to the virtualization game.”

Pitt gave context on the progression of networking in a larger perspective as the technology began with mainframes years ago. “Mainframe computers went to open markets and open interfaces. When you have competition, you have to fit to many more people’s needs.” So, naturally, as providers have to adjust to what users want, they are trending towards interfaces that allow them to do more things in less costly ways.

In order to centralize an operating system, which is what software-defined networking aims to do, the network has to enable communication between the packet layer and the control layer. The protocol dubbed OpenFlow enables such communication. “We have separated forwarding from control,” said Pitt. The ONF works closely on this project. But when the switches are now forwarding to the control layer, how do they know what to do? According to Pitt, this is where OpenFlow comes into play.

With OpenFlow, you can define flow between these network layers the way you want because it’s an open interface to packet forwarding. “When you separate forwarding from control, you have to have a way for them to communicate – that is OpenFlow protocol,” explained Pitt. “This is where the value is for the business: Being able to program [the flow] the way that you want.”

 So how does this translate for network operators? If you want to know, ask Google. Pitt revealed that Google converted to a 100 percent OpenFlow global inter-data center wireless area network (WAN) with centralized routing. Now it has 95 percent network utilization.

How Pitt envisions SDN bringing the network “back to the people” is that it will enable the programmer to rule. With SDN as a new norm for networks, operation will be user-driven (which is essentially what “the cloud” is all about, anyway).

“There is going to be a generational shift in networking. Technology has gotten us to the point where it’s a natural evolution. We have gone from protocols to APIs. We have gone from hardware and appliances to open software. We want to move networking into this realm of usability.”