An approach is provided for managing bandwidth in a data network. Capacity is allocated on a communication channel, which can be utilized for transporting data traffic or support network administrative functions (e.g., ranging), for a terminal to transmit data over the communication channel. In anticipation of the terminal having to transmit additional data, additional capacity is allocated on the communication channel for the terminal prior to receiving a request for bandwidth by the terminal. The anticipatory allocation is determined according to loading of the data network. This approach as particular applicability to shared capacity systems, such as a satellite communication system.