A method and apparatus for reliably transmitting data by transmitting a plurality of radio link control (RLC) unacknowledged mode (UM) protocol data units (PDUs) over at least one primary channel and at least one auxiliary channel. If at least one RLC UM PDU is missing from the data transmitted over the primary channel, the missing RLC UM PDU is obtained from the auxiliary channel after a predetermined delay. A service data unit (SDU) is completed by combining PDUs received over the primary channel with at least one missing PDU received over the auxiliary channel. The SDU is sent to an application layer. If the missing PDU cannot be obtained before a predetermined time period expires, the transmitted data is deleted. The RLC UM PDUs may be used for streaming multicast applications.