An SDN OpenFlow controller based on floodlight(https://github.com/floodlight/floodlight), we accomplished QoS function with this SDN Controller.
Floodlight is the leading open source SDN controller. It is supported by a community of developers including a number of engineers from Big Switch Networks (http://www.bigswitch.com/).
OpenFlow is a open standard managed by Open Networking Foundation. It specifies a protocol through switch a remote controller can modify the behavior of networking devices through a well-defined “forwarding instruction set”. Floodlight is designed to work with the growing number of switches, routers, virtual witches, and access points that support the OpenFlow standard.