types of reaction
sndr sndr proxy rcvr proxy rcvr
preserve delay buffer buffer buffer
delay mark f/b mark f/b mark
re-xmt drop f/b nack f/b nack
less - drop suppress nack suppress nack
recode mark f/b mark f/b mark
recode f/b nack f/b nack f/b nack
- - f/b drop layer f/b drop layer
- explicitly instruct sender what to do
- sender adapts to thinner pipe through f/b
which reaction depends on relative strengths in vector
- but declarative isn’t enough (need some prescription)