Feb 06 2014

The Second Coming of Software-Defined Networking

SDN is already changing the world. Some researchers are now at work to show its greater potential.

Advancing education and research via technical innovation is the mission of Internet2, a nonprofit organization that comprises more than 200 U.S. universities and dozens of state and education networks, as well as government agencies and ­major ­corporations.

The outfit operates the ­Internet2 Innovation Platform, an open, ­national-scale 100 Gigabit ­Ethernet network that ­leverages ­software-defined networking (SDN) principles and the OpenFlow protocol, providing members an ­end-to-end ­network path ­facilitating ­data-intensive science and the innovative use of networks.

With its first Internet2 ­Innovative ­Application Awards, it is also aiming to show the potential of running an Advanced Layer 2 network with new and open-source, SDN-enabled ­applications. "We need to kick-start the ­application space to show what is possible," says Eric Boyd, senior ­director of strategic projects, ­Internet2 Network Services. "We wanted to significantly push the ball forward and show what you can do."

Eight applications were recently cited, among them some more traditional solutions focused on finding efficient places to source data as well as network routes and destinations, but also some that "took concepts around SDN and exploited that in new ways," says ­Grover ­Browning, Internet2 senior director of network innovation. The Black Box Congestion ­Control project from Mo Dong, research assistant at the University of Illinois at Urbana-Champaign, is one such project.

What's in the Black Box?

"When you virtualize the network and slice it, what you get is your own network," Browning says. "Dong realized that when you have what looks like your own single-purpose–built network, you don't have to follow the rules enforced in the transmission control protocol [TCP] for fairness" to avoid any one user ­monopolizing the network in multiuser environments.

While solutions exist to modify TCP to meet the needs of specific scenarios, Dong's approach focuses on "refactoring the whole data ­protocol from ground zero, and ­basically redesigning the whole thing to make it fit to the current network scenario."

Today's scaled-up Internet will continuously violate the assumptions that have driven the controlled behavior of TCP and all its modifications to date, Dong says. Those ­include packet-level events that ­dictate backing down transmission rates when there's a packet loss due to an underlying supposition that the loss ­indicates network congestion.

The Black Box bases its control mechanism on meaningful network performance metrics rather than assumptions so that "each sender using the same utility function can selfishly optimize their own performance," Dong says, even if there is no isolation in-network. A recent demo showed "other applications and traditional flows were not impacted by his own selfish use of his slice," Browning says.

Next up for all of the open-source apps entered in the awards: enabling their technology transfer to the commercial sphere.

"The goal is for others to incorporate this code into their own ­applications," Boyd says.