QUIRL: Flexible QUIC Loss Recovery for Low Latency Applications

A growing number of Internet applications require low latency. Unfortunately, most of these applications cannot use the rich features of the QUIC protocol since it only uses retransmissions to cope with packet losses. We propose, implement and evaluate QUIRL, a revisit of the QUIC loss recovery mechanism. QUIRL relies on Forward Erasure Correction (FEC) only if it is needed by the application’s latency requirements and uses classical retransmissions otherwise. We implement QUIRL and evaluate its performance for real-time video and HTTP/3. Compared to previous works adding FEC to QUIC, QUIRL is the first to be evaluated with and obtain significant performance improvements for popular applications over real lossy networks. Our evaluation shows that for video QUIRL improves the video quality while meeting strict delay requirements. For HTTP/3 transfers, QUIRL efficiently reduces the tail latency when packet losses occur without causing harm when there are no losses. We confirm these results using emulation over a wide ranges of bandwidth, delays and loss scenarios. We release our QUIRL implementation to encourage other researchers and industry to explore in more details the use of FEC in QUIC.