Today, OpenDaylight is an open source platform for network programmability to enable SDN and create a solid foundation for Network Functions Virtualization (NFV) for networks at any size and scale. OpenDaylight software is a combination of components including a fully pluggable controller, interfaces, protocol plug-ins, and applications. The Northbound (programmatic) and Southbound (implementation) interfaces are meant to be clearly defined and documented APIs for network applications.

via OpenDaylight: Open Source Programming to the Software-Defined Network.

OpenDaylight delivered its first developer release, Hydrogen, on February 5th, 2014.