Redundant coding
Effectiveness of single-path FEC is limited
- Routing failures heal slowly [Labovitz ’00]
- Packet loss is bursty [Bolot ’93, Paxson ’99]
Use erasure coding across paths
- Erasure codes enable efficient encodings, but
- High efficiency requires large numbers of packets
- Decoding requiring multiple packets increases latency
- Carousel-based techniques add delay
- Duplicate packets can actually decrease latency
- But may not be as bandwidth efficient
- Hop-by-hop retransmission decreases recovery time