Which elements can be controlled with an SDN controller for an SDN-enabled switch?

Quality of service (QoS) can be directly controlled with an SDN controller. The SDN controller will push programming to the SDN-enabled switch so that the switch can control the flow of traffic. CPU and memory utilization can be reported on, and arguably programming can be pushed out to alleviate central processing unit (CPU) and memory utilization, but CPU and memory utilization is not directly controlled with an SDN controller. The forwarding of traffic is a responsibility of the data plane, which can be changed by the control plane. However, the SDN controller does not forward packets explicitly; that is the function of the switch.