Enhanced acknowledgement and retransmission mechanism

Protocol data units (PDUs) associated with a packet stream are transmitted with sequence numbers to support reordering and selective acknowledgement. A selective acknowledgement (SACK) message may be used to indicate at least one sequence number of a lost or corrupted PDU which was not properly received by the receiving device. Responsive to the SACK message, the lost or corrupted PDU is retransmitted via a different path of the network, different from the path used to transmit the original PDU. Lost or corrupted PDUs may not be retransmitted if the estimated retransmission delay is greater than a delay tolerance associated with the quality of service requirements of the application. Instead, a control message (i.e. "cut losses" message) may be transmitted to indicate that PDUs earlier than a particular sequence number will not be transmitted.