Software-Defined Networking (SDN) and OpenFlow are among the hot topics in the networking research and development domain both in industry and academia. There are plenty of active open source projects around the SDN and OpenFlow that form OpenFlow software-based switches to OpenFlow controllers, orchestration tools, network virtualization tools, simulation and testing tools, and so on. The main idea here is to give a brief and condensed summary of active open source projects around SDN and OpenFlow. We will cover the following open source projects:

• Controllers: Beacon, Floodlight, Maestro, Trema, FlowER, Ryu, Open Network Operating System (ONOS), Atrium, and OpenContrail
• Miscellaneous: FlowVisor, FlowSim, Avior, RouteFlow, OFlops and Cbench, OSCARS, Twister, FortNOX, Nettle, Frenetic, and OESS.

This chapter gives pointers to the important projects that network engineers can utilize in their operational environment.