The technology consists of three parts: flow tables installed on switches, a controller and a proprietary OpenFlow protocol for the controller to talk securely with switches. For the purposes of OpenFlow development, Cisco, HP, Juniper and NEC have added OpenFlow to switches and routers being used in the project. OpenFlow is not generally available.

With the feature, flow tables are set up on switches. Controllers talk to the switches via OpenFlow Protocol, which is secure, and impose policies on flows. So, for example, a simple flow might be defined as any traffic from a given IP address. The rule governing it might be to route the flow through a given switch port. With its knowledge of the network, the controller could set up paths through the network optimized for speed, fewest number of hops or reduced latency, among other characteristics, McKeown says.

With current switches and routers, policies within them controlled by proprietary software determines the path traffic takes. OpenFlow can take control of how traffic flows through the network out of the hands of the infrastructure -- the switches and routers -- and put it in the hands of the network owner (such as a corporation), individual users or individual applications. McKeown says.

OpenFlow is being demonstrated this week at Global Environment for Network Innovations (GENI) Engineering Conference at HP Labs in Palo Alto. Researchers in the OpenFlow Consortium are demonstrating the feature in an experimental network between California and Japan. In the demo, players in both countries are playing a computer shooting game, and OpenFlow is being used to locate a virtual server on the network so minimize the average latency each player experiences.

In the demo, the game server is located on a virtual machine. Using OpenFlow, the virtual server copies itself to another physical server at the optimal location in the OpenFlow network to equalize latency, McKeown says. While the demonstration is not a practical business application of the technology, it does show some of its capabilities, he says.