A control application of some embodiments allows a user to enable a logical switching element for Quality of Service (QoS). QoS in some embodiments is a technique to apply to a particular logical port of a logical switching element such that the switching element can guarantee a certain level of performance to network data that a machine sends through the particular logical port. The control application of some embodiments receives user inputs that specify a particular logical switch to enable for QoS. The control application may additionally receive performance constraints data. The control application in some embodiments formats the user inputs into logical control plane data. The control application in some embodiments then converts the logical control plane data into logical forwarding data that specify QoS functions.