Traffic control with tc

October 12, 2021 - Tags: linux

tc (traffic control) is a great tool to “show / manipulate traffic settings” in the Linux kernel. With the qdisc command it’s e.g. possible to introduce delays:

tc qdisc add dev eth0 root netem delay 200ms # exact delay
tc qdisc change dev eth0 root netem delay 200ms 20ms # 20ms uniform variation
tc qdisc change dev eth0 root netem delay 200ms 20ms 20% # 20ms uniform variation with correlation

errors:

tc qdisc change dev eth0 root netem corrupt 1%

loss:

tc qdisc add dev eth0 root netem loss 1%

and duplicates:

tc qdisc change dev eth0 root netem duplicate 1%

To view the current settings use:

tc qdisc show # all devices
tc qdisc show dev eth0 # a specific device

To delete rules use:

tc qdisc del dev eth0 root