Abstract: A computing system manages communications congestion by selecting a transmission rate differently in different operating modes. In a delay-plus-loss mode, the transmission rate is selected as the lesser of a rate that would be selected by loss-based algorithm or by a delay-based algorithm. In a loss-based mode, the transmission rate is selected as the lesser of a rate that would be selected by loss-based algorithm, on one hand, and the maximum of a rate that would be selected by a delay-based algorithm or a rate proportional to the maximum estimated link rate divided by the number of data flows estimated to be competing for link bandwidth on the other hand. A database may be maintained of observations of network and link performance over time, where the database contains such information as the maximum estimated link rate capacity, minimum delays, and minimum losses.