Openflow, an open source protocol, enables software-defined networking by allowing a server-based controller to abstract and centralize the control plane of switches and routers. It has enjoyed plenty of buzz since Interop Las Vegas last year.

HP has had an experimental version of OpenFlow support on its switches for a couple years, but it was only available through a special research license. Saar Gillai, CTO of HP Networking, said his company is making OpenFlow generally available because HP customers are demanding it for use in production networks.

This position contrasts sharply with Cisco Systems’ apparent view of Openflow. At Cisco Live London this week, Cisco announced availability of new network virtualization technologies, including VXLAN support on its Nexus 1000v virtual switch and Easy Virtual Network (EVN), a WAN segmentation technology based on VRF-lite. But OpenFlow was not part of the discussion. In her keynote at Cisco Live, Cisco CTO Padmasree Warrior said her company wants to make software a core competency in 2012 and make networks more programmable, a key feature of software-defined networking. When asked where OpenFlow fits into this vision, Warrior said that software-defined networking is “broader than Openflow.” And Cisco VP of data center switching product management Ram Velaga said Openflow is “not production-ready.”

Gillai said HP is seeing a lot of interest in using OpenFlow in production networks. He said service providers are looking at using it to get more granular control of their networks. Enterprises want to use OpenFlow to make their data center networks more programmable. Particularly, enterprises that are using Hadoop to run large distributed applications with huge data sets are interested in using OpenFlow and software-defined networking for job distribution.

“We’ve spoken to customers who would like to set up a certain circuit with OpenFlow for the Hadoop shop to use at certain times of day,” Gillai said.

Of course, Warrior is right when she says software-defined networking is broader than Openflow. Arista Networks has been offering an open and non-proprietary approach to software-defined networking without OpenFlow for a couple of years.

But OpenFlow still has plenty of buzz, and big backers. HP’s support is significant, given its position as the number two networking vendor. And last week, IBM announced a joint solution with a new top-of-rack OpenFlow switch and NEC’s ProgrammableFlow controller.

IBM and HP. Those are two very big companies with a lot of customers.