A method for mapping quality of service (QoS) flows to data radio bearers includes determining a cumulative data volume of a first QoS flow; and determining that the cumulative data volume of the first QoS flow meets a specified data threshold, and based thereon: mapping the first QoS flow to a first data radio bearer, where a maximum data volume of the first data radio bearer is less than a maximum data volume of the first QoS flow; and transmitting a packet of the first QoS flow over the first data radio bearer.