A network switch includes a transmitter and a controller. The transmitter is configured to selectively terminate transmission of a first frame from the network switch. The controller is configured to, in response to the transmitter terminating the transmission of the first frame, increment respective attempt counts for a first class of service associated with the first frame and all classes of service lower than the first class of service, determine whether any of the respective attempt counts is greater than a predetermined attempt threshold, and, in response to any of the respective attempt counts being greater than the predetermined attempt threshold, discard frames having the first class of service and frames having any of the classes of service lower than the first class of service.