Abstract: Bandwidth is adaptively allocated in an upstream channel of a layered data communication network such as that used for carrying messages from a number of subscriber units (250, 252, . . . , 254) to a central controller (210), for example, to allow the subscriber units to send data for Internet access, videoconferencing, or voice communication. A running total of unallocated bandwidth (BWA(j)) is maintained in successive control intervals. A traffic count (C(i)) is determined for each subscriber unit by measuring the bandwidth which is used, for example, by counting the number of slots used in a control interval. The assigned bandwidth (B(i)) of the subscriber units is then adjusted when a ratio (K) of the traffic count to the assigned bandwidth is at or below a lower threshold (T1), and the running total of unallocated bandwidth is incremented by the decrease in the assigned bandwidth.