Thomas Kunz
Systems and Computer Engineering
12
Reliable BCAST
nEach node keeps cache of recently transmitted packets (FIFO, small)
nEach node, upon receiving packet X from sender S, checks whether it received packet X-1 from that sender
ØIf not, broadcast retransmission request (NACK) to 1-hop neighbors
ØNeighbors listen to overhear other retransmission and cancels theirs
nFirst 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)
nAdded feature: NACK throttle