This paper describes an architecture to support QoS flows in an OpenFlow environment with a centralized `controller' and many `forwarders.' The paper primarily focuses on the analytical framework for optimization of the QoS flow routing, and the functionality needed within the controller and forwarders to efficiently support QoS. We also describe the control layer messaging between the controller and forwarder to set up queues, detect congestion and reroute traffic streams that require QoS. We provide some experimental results to route Scalable Video Coding (SVC) encoded video comprised of a base layer, which requires error free decoding and hence QoS, and one or more enhancement layers, which are error resilient and hence generate best effort traffic.