TCP_BBR_Modified

How to compile tcp_bbr_modified algorithm on CentOS7

• Install the latest version of Linux kernel, headers and develoment tools.

  rpm --import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org
  rpm -Uvh http://www.elrepo.org/elrepo-release-7.0-2.el7.elrepo.noarch.rpm
  yum --enablerepo=elrepo-kernel install kernel-ml -y
  yum -y remove kernel-headers
  yum --enablerepo=elrepo-kernel install kernel-ml-headers -y
  yum --enablerepo=elrepo-kernel install kernel-ml-devel -y
  

  Then doegrep ^menuentry /etc/grub2.cfg | cut -f 2 -d \'to see the sequence of alreadly installed kernels and choose the one you’ve installed just now.

  For instance, if you want choose the first one to boot by dedault then do grub2-set-default 0 The sceond one, do grub2-set-default 1, so on and so forth.

  grub2-set-default 0 
  reboot
  

• Install GCC with version number grater than 4.9 via CentOS Software Collections

  yum -y install centos-release-scl
  yum -y install devtoolset-4-gcc*
  scl enable devtoolset-4 bash
  

  After installing GCC via scl, dowhich gccto check if is was already installed correctly, it will return real path of GCC generally . Then do gcc --version to check the verion number, it would be 5.33.

• Download source code of tcp_bbr_modified and generate the Makefile

  wget https://raw.githubusercontent.com/GEM7/TCP_BBR_Modified/master/tcp_bbr_modified.c
  echo "obj-m:=tcp_bbr_Modified.o" > Makefile
  

• Compile it and initialization

  make -s -C /lib/modules/$(uname -r)/build M=`pwd` modules CC=`which gcc`
  cp -rf ./tcp_bbr_modified.ko /lib/modules/$(uname -r)/kernel/net/ipv4
  depmod -a 
  modprobe tcp_bbr_modified
  

• Set it as the default TCP congestion control algorithm

  echo "net.core.default_qdisc = fq" >>/etc/sysctl.conf
  echo "net.ipv4.tcp_congestion_control = bbr_modified" >>/etc/sysctl.conf
  

• Check if bbr_modified works

  lsmod | grep bbr
  

  if you see words including bbr_modified, then it works.