An exemplary technique disclosed herein is that the transmitter of a VOIP stream can assess the psycho-acoustic importance of each packet, and then use a protocol that supports redundant transmission to retransmit only the packets that are judged to be important for voice quality and intelligibility. Illustratively, a packet containing a plosive might be retransmitted redundantly because of its disproportionate contribution to intelligibility, but a packet that occurs entirely within a long-duration fricative transmitted only once. An exemplary aspect may also support multiple levels of transmission redundancy based on multiple levels of packet importance, with the levels varying based on the relative psycho-acoustic importance of each packet and/or the degree of network congestion.