ABSTRACT1The bandwidth-on-demand (BoD) access mechanism plays a key role in DVB-RCS satellite systems in order to optimize bandwidth utilization. Two algorithms intervene in this mechanism, namely the bandwidth allocation algorithm and the bandwidth request algorithm. In this paper a bandwidth request algorithm is proposed. An adaptive version of the algorithm is also presented, which allows for an easy control of the queue size at the terminal even in changing traffic conditions. An event-driven simulator of the BoD loop has been developed and used to evaluate the performance of the proposed algorithm. Simulations have carried out for different combinations of Poisson and VoIP traffic. They show that the algorithm reacts correctly to sudden changes of the input rate and of the received allocation.