OpenFlow is a that gives access to the of a or over the network. In simpler terms, OpenFlow allows the path of network packets through the network of switches to be determined by software running on multiple routers (minimum two of them - primary and secondary - has a role of observers). This separation of the control from the forwarding allows for more sophisticated traffic management than what is feasible using (ACL)s and routing protocols. Its inventors consider OpenFlow an enabler of "".

A number of network switch and router vendors have announced their intention to support OpenFlow, including , , , , , , , , and . Some network implementations use the protocol to manage the network forwarding elements. OpenFlow is mainly used between the switch and controller on a secure channel.

Version 1.1 of the OpenFlow protocol was released on February 28, 2011 and is still maintained at openflow.org, but new development of the standard was managed by the (ONF). In December 2011, the ONF board approved OpenFlow version 1.2 and published it in February 2012.

Indiana University in May 2011 launched the in conjunction with the Open Networking Foundation to test how well different vendors' Software-Defined Networking and OpenFlow products work together.

In February of 2012, Big Switch Networks released an package for OpenFlow software. The company has released Floodlight, an Apache-licensed OpenFlow Controller.

In February 2012 HP said it is taking its first leap into OpenFlow-enabled network equipment, supporting the standard on 16 of its Ethernet switch products as it attempts to gain a foothold in a market likely to receive significant attention.

In April 2012 Google's 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.

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