A method of operating in a network in which a plurality of stations communicate over a shared medium (e.g., using a carrier sense multiple access (CSMA) service). The stations contend for access to the shared medium using a contention procedure that relies on a priority level, wherein transmissions with a lower priority level have a reduced chance of gaining access to the shared medium during a contention process. Selected stations are given the capability of temporarily promoting the priority level of transmissions they are attempting to make. The priority level is increased during an interval to reduce the chance that other stations gain access to the shared medium during that interval, and the priority level is restored to its normal level following the interval.