BBR, the new kid on the TCP block

It's available in Ubuntu 17.04. Add these lines to /etc/sysctl.conf:

    net.core.default_qdisc=fq
    net.ipv4.tcp_congestion_control=bbr

I got 400Mbps (on a 1Gbps link) from Seattle to New York with a single TCP-BBR stream, vs ~50Mbps before :-).

How are you measuring this?

You could probably saturate that link with a single TCP stream -- even without BBR -- by simply choosing the correct send and receive buffer sizes in your test program. (I assume you're using iperf or a similar program to perform your tests.)

BBR and other congestion-control algorithms come into play when the underlying IP network is congested. To test them, you have to have control of the congestion rate of the underlying circuit, which you might not have if you're testing this on an ordinary public IP network.

Thank you! This is helpful also about fq vs fq_codel - https://groups.google.com/forum/m/#!topic/bbr-dev/4jL4ropdOV...