The invention discloses a method (200, 300, 400) for traffic control in a cellular telephony system (100) comprising a number of cells, each cell comprising at least one Radio Base Station, RBS, (170). The system (100) comprises at least one Radio Network Controller, RNC, (110 130 150), for the control of a number of Radio Base stations. The traffic between an RBS and an RNC comprises a number of flows. The invention is intended for the control of flows from the Radio Base Stations to their RNC. The method uses one control function for each flow from each of said Radio Base Stations, and also comprises a congestion detection function (220) which detects the presence or absence of congestion in the traffic from an RBS to an RNC, and which, upon detection of congestion reduces the bit rate of the congested traffic, and in the absence of congestion, increases the bit rate of the previously congested traffic.