UDP does not back off in face of congestion, it has a stiff behavior
We modified iperf to allow it to create UDP traffic with
a sinusoidal time behavior, following
an idea from Tom Hacker
See how TCP responds to varying cross-traffic
Used 2 periods of 30 and 60 seconds and amplitude varying from 20 to 80 Mbps
Sent from 2nd sending host to 2nd receiving host
while sending TCP from 1st sending host to 1st receiving host
As long as the window size was large enough all protocols converged quickly and maintain a roughly constant aggregate throughput
Especially for P-TCP & Bic-TCP