In an LTE (Long Term Evolution) system, a radio access network (RAN) is configured to detect and report congestion radio congestion to a core network. RAN congestion may be indicated by lost, discarded, or retransmitted data packets. In response to being notified of congestion at the RAN, the core network of the system modifies properties of data bearers and data flows between the core network and the RAN, such as by modifying QoS commitments where possible and remapping data flows.