Also, OpenFlow allows switches from different vendors — often each with their own proprietary interfaces and scripting languages — to be managed remotely using a single, open protocol.
This way, routing decisions can be made periodically or ad hoc by the controller and translated into rules and actions with a configurable lifespan, which are then deployed to a switch's flow table, leaving the actual forwarding of matched packets to the switch at wire speed for the duration of those rules.
OpenFlow allows direct access to and manipulation of the forwarding plane of network devices such as switches and routers, both physical and virtual (hypervisor-based).
It is the absence of an open interface to the forwarding plane that has led to the characterization of today's networking devices as monolithic, closed, and mainframe-like.
[16][17] Indiana University in May 2011 launched a SDN Interoperability Lab in conjunction with the ONF to test how well different vendors' software-defined networking and OpenFlow products work together.
[22] In April 2012, Google's Urs Hölzle described how the company's internal network had been completely re-designed over the previous two years to run under OpenFlow with substantial efficiency improvement.