Experimental evaluation of BBR congestion control

BBR is a recently proposed congestion control.
Instead of using packet loss as congestion signal, like many
currently used congestion controls, it uses an estimate of the
available bottleneck link bandwidth to determine its sending
rate. BBR tries to provide high link utilization while avoiding to
create queues in bottleneck buffers. The original publication of
BBR shows that it can deliver superior performance compared
to C UBIC TCP in some environments. This paper provides an
independent and extensive experimental evaluation of BBR at
higher speeds. The experimental setup uses BBR’s Linux kernel
4.9 implementation and typical data rates of 10 Gbit/s and
1 Gbit/s at the bottleneck link. The experiments vary the flows’
round-trip times, the number of flows, and buffer sizes at the
bottleneck. The evaluation considers throughput, queuing delay,
packet loss, and fairness. On the one hand, the intended behavior
of BBR could be observed with our experiments. On the other
hand, some severe inherent issues such as increased queuing
delays, unfairness, and massive packet loss were also detected.
The paper provides an in-depth discussion of BBR’s behavior in
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different experiment setups.