An AP having a message waiting time that provides proper QoS while losing minimal communication bandwidth, setting parameters for each level of QoS in response to a measure of the degree of contention for that level of QoS, and in response to a measure of the degree of contention for those levels of QoS with higher priority, and setting waiting time parameters in response to a stochastic model of contention at each level of QoS. Changes in contention at each level of QoS affect the AP's waiting time parameters for that level of QoS and also for levels of QoS with lower priority. Operational parameters might include contention window time, AIFS time, and back-off value(s), and might be modified in response to message QoS.