A hybrid gateway includes functionality that allows bandwidth on a network (such as a satellite link) to be dynamically allocated and enforced. The hybrid gateway compares the thresholds defined for a requesting terminal's level of service and its measured running average data throughput to determine if the requesting terminal's bandwidth should be reduced (throttled). The hybrid gateway intercepts requests made by the requesting terminals and, if necessary, reduces the advertized window size of requests made by the requesting terminal, thereby reducing the transmission speed of the link and therefore the bandwidth of the link.