A method and apparatus are provided for implementing automatic congestion avoidance for differentiated service flows in a communications network. A bandwidth control signal representing congestion information is identified. Responsive to the identified bandwidth control signal, dual transmit probabilities are calculated for each flow. The dual transmit probabilities include a first transmit probability for a first color and a first transmit probability for a second color. A marked color for a packet is identified. The marked packet color and the calculated dual transmit probabilities are selectively utilized for making a packet discard determination.