A method is disclosed for controlling, according to an additive increase multiplicative decrease (AIMD) principle, the bandwidth sharing among contending traffic flows over a transport network between a radio network controller and a radio base station. According to the method, a relative bit-rate (RBR) is determined (210) for each traffic flow; and the bit-rates of said traffic flows are controlled (220) such that additive increase operations of said AIMD principle depend on the respective RBR of each traffic flow. Embodiments of the invention strive at supporting Gold, Silver and Bronze HSDPA and/or EUL bit-rate subscriptions over a single TN QoS class.