Fixing bufferbloat on your home network with OpenBSD 6.2 or newer

Re:Fixing bufferbloat on your home network with OpenBSD 6.2 ... by y0ssar1an on Tuesday July 03, 2018 @11:06PM (#17455036)

Fix it on Linux by enabling BBR TCP congestion control.

  cat << EOF >> /etc/sysctl.conf
  net.core.default_qdisc=fq
  net.ipv4.tcp_congestion_control=bbr
  EOF
  sudo sysctl -p

1. You will need a recent kernel.

2. net.ipv4.tcp_congestion_control=bbr applies to IPv6 too.

3. You must set the queuing discipline to fq or it won't work.

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Re:Fixing bufferbloat on your home network with OpenBSD 6.2 ... by jdc on Wednesday July 04, 2018 @01:14AM (#17455381)

Running 30mbps fibre and getting marginally better results (upload especially) with these settings:

    net.core.default_qdisc = fq_model
    net.ipv4.tcp_congestion_control = cubic

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Re:Fixing bufferbloat on your home network with OpenBSD 6.2 ... by AstralStorm on Wednesday July 04, 2018 @03:18PM (#17458982)

CuBIC tends to produce funny shark tooth transfer rate patterns on an uneven connection especially in presence of packet loss and unexpected congestion.

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Re:Fixing bufferbloat on your home network with OpenBSD 6.2 ... by aorth on Wednesday July 04, 2018 @03:32AM (#17455784)

Guessing you meant fq_codel instead of fq_model?

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Re:Fixing bufferbloat on your home network with OpenBSD 6.2 ... by jdc on Friday July 06, 2018 @01:11AM (#17469021)

Yeah, good catch.

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Re:Fixing bufferbloat on your home network with OpenBSD 6.2 ... by cesarb on Wednesday July 04, 2018 @06:28AM (#17456346)

Doesn't this have to be done on the sending computer? Doing it on your computer would make a difference only when uploading; when downloading, the server you're downloading from would also need this setting.

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Re:Fixing bufferbloat on your home network with OpenBSD 6.2 ... by sliken on Wednesday July 04, 2018 @02:57AM (#17455670)

300 mbit connection, ubuntu 18.04, linux-4.15.0 and I still get an F after the above tweaks.

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Re:Fixing bufferbloat on your home network with OpenBSD 6.2 ... by JackMinello on Wednesday July 04, 2018 @02:15AM (#17455548)

On newer kernel is no longer required to install the "fq" qdisc to use BBR

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Re:Fixing bufferbloat on your home network with OpenBSD 6.2 ... by wtallis on Wednesday July 04, 2018 @02:22AM (#17455578)

More specifically, it appears to require this commit[1] that's in kernels 4.13 and later.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-ne...

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Re:Fixing bufferbloat on your home network with OpenBSD 6.2 ... by aorth on Wednesday July 04, 2018 @03:41AM (#17455805)

Interesting! From a related discussion in 2017 on the bbr-dev mailing list:

  BBR will run well with fq_codel only after linux-4.13 (not yet released)

  Before linux-4.13, BBR _needs_  fq packet scheduler.

  fq is not fq_codel.

See: https://groups.google.com/forum/#!topic/bbr-dev/4jL4ropdOV8

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Re:Fixing bufferbloat on your home network with OpenBSD 6.2 ... by comesee on Tuesday July 03, 2018 @11:12PM (#17455052)

Does this work for linux routers or just the endpoint machine?

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Re:Fixing bufferbloat on your home network with OpenBSD 6.2 ... by y0ssar1an on Tuesday July 03, 2018 @11:53PM (#17455166)

Just the endpoint machine.

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