An SDN architecture, for a cellular communications system, is described herein that includes a Quality of Service (QoS) provisioning framework to provision and manage traffic flows in the cellular communications system. The described architecture separates the control plane and the user plane for the transport of the user plane traffic. Network entities in the SDN architecture, such as a network controller, can detect and react to changes in network state (e.g., load conditions) to route or reroute traffic flows in the network. QoS and routing parameters may be determined for the network traffic on a per-flow basis, even when multiple flows are associated with a single service request.