1.输入该命令按回车键：rpm --import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org

2.输入该命令按回车键：rpm -Uvh http://www.elrepo.org/elrepo-release-7.0-2.el7.elrepo.noarch.rpm

3.输入该命令按回车键：yum --enablerepo=elrepo-kernel install kernel-lt -y

4.输入该命令按回车键查看记录内核名称：cat /boot/grub2/grub.cfg | grep menuentry

5.根据查找内核名称设置输入该命令按回车键：grub2-set-default 'CentOS Linux (5.4.260-1.el7.elrepo.x86_64) 7 (Core)

6.输入该命令按回车键：grub2-editenv list

7.输入该命令按回车键重启后再连接：reboot

8.输入该命令按回车键：echo "net.core.default_qdisc=fq" >> /etc/sysctl.conf

9.输入该命令按回车键：echo "net.ipv4.tcp_congestion_control=bbr" >> /etc/sysctl.conf

10.输入该命令按回车键：sysctl -p

11.输入该命令按回车键出现如图提示表示开启成功：sysctl -n net.ipv4.tcp_congestion_control