Dan Pitt, an early champion of software-defined networking (SDN) and the OpenFlow protocol, has stepped down as executive director of the Open Networking Foundation (ONF), SDxCentral has learned.

ONF Technical Director Rick Bauer is filling Pitt's spot on an interim basis “while a formal candidate search is completed in the coming months,” the ONF says in a prepared statement. His job will be include keeping the ONF “focused on the growth and commercialization of SDN,” the statement reads.

An ONF spokeswoman says Pitt left to pursue other, unspecified opportunities. Pitt did not immediately respond to a request for comment.

Pitt was the ONF's first and only employee in 2011, when the organization was founded by Deutsche Telekom, Facebook, Google, Microsoft, Verizon, and Yahoo. A total of 17 companies had become ONF members by the time the organization formally launched in March 2011.

The ONF serves as caretaker of the OpenFlow standard, but its core mission was to promote SDN. Few people had heard the term SDN back in 2011, and those who did often had a response of “Eh, we've done that,” thinking back on programmable-network efforts of the past decade or so.

“Dan was pretty instrumental in pulling things together and getting them off the ground, in a way that transcended a group of enthusiasts at Stanford,” writes Martin Casado in an email to SDxCentral. Casado is now a venture capitalist with Andreessen Horowitz, but was one of those Stanford enthusiasts pre-2011. Casado, of course, went on to help found Nicira, which was acquired by VMware and helped SDN rocket into mainstream networking discussions.

“I remember meeting with him when he was still considering joining [the ONF], and he had a very strategic view of what the foundation could do. And he did that. ONF really became an industry icon under his leadership,” Casado writes.

With Pitt's help, openness became a hallmark of SDN, both in the use of open source code and in the encouraging of open architectures that any vendor could participate in.

“Dan did a great job of developing and nurturing an open networking community. He also understands the importance of fostering collaboration not just within his community but across communities, fostering collaboration with the MEF, ODL [OpenDaylight Project], and even OCP [Open Compute Project],” writes Neela Jacques, OpenDaylight's executive director, in an email to SDxCentral.

“What has impressed me most working with Dan is the integrity with which he did his job — always seeking to understand more deeply, questioning and challenging but with a willingness to re-examine his own beliefs, and a strong dedication to truly serving the interests of his members/community,” Jacques writes.

He adds that Pitt's biggest accomplishment was to broaden the ONF's focus beyond OpenFlow and into areas such as architectures and testing. Pitt also worked to get the ONF engaged with other open source projects.

“Dan has been, on one hand, one of the industry's leading spokespeople for the need for networks to evolve, but also quietly working to bring folks together to actually achieve much of the blocking and tackling to get there,” Jacques writes.