OpenDaylight - OpenDaylight is an open platform for network programmability to enable SDN and create a solid...
GNS3 - GNS3 is a graphical network simulator that allows simulation of complex networks.
Ubiquiti UniFi - UniFi is the SDN platform for Ubiquitis UniFi series
ns-3 - a discrete-event network simulator for internet systems
Beehive SDN Controller - A distributed SDN controller with OpenFlow support
NetSim - NetSim software was created to simulate various Cisco systems. Cisco software is known around the world as being one of the best network, routing and switch systems for businesses and private use. Read more about NetSim.