•Each node keeps cache
of recently transmitted packets (FIFO, small)
•Each node, upon
receiving packet X from sender S, checks whether it received packet X-1 from that sender
–If not,
broadcast retransmission request (NACK) to 1-hop neighbors
–Neighbors
listen to overhear other retransmission and cancels theirs
•First set of
experiments revealed that under high traffic load, too many NACKs were issued, flooding the network and
resulting in overall worse
performance (70% PDR for 10 sender scenarios)
•Added
feature: NACK throttle
•Results: consistent
improvement in PDR compared to best-effort version, at cost of slightly higher packet latency (all
performance differences
statistically significant at 99% confidence level).