tc
Linux traffic control and shaping
TLDR
Add constant delay
$ sudo tc qdisc add dev eth0 root netem delay 100ms
Add variable delay$ sudo tc qdisc add dev eth0 root netem delay 100ms 20ms
Add packet loss$ sudo tc qdisc add dev eth0 root netem loss 5%
Limit bandwidth$ sudo tc qdisc add dev eth0 root tbf rate 10mbit burst 32kbit latency 400ms
Show active policies$ tc qdisc show dev eth0
Delete all rules$ sudo tc qdisc delete dev eth0
Change rule$ sudo tc qdisc change dev eth0 root netem delay 50ms
SYNOPSIS
tc [OPTIONS] OBJECT COMMAND
DESCRIPTION
tc (traffic control) configures kernel packet scheduling, shaping, and filtering. It can simulate network conditions like latency, packet loss, and bandwidth limits for testing or quality of service management.
PARAMETERS
qdisc
Queuing discipline - manage packet queuingadd
Add a new traffic control policydelete
Remove traffic control policychange
Modify existing policyshow
Display current policiesnetem
Network emulation (delay, loss, corruption)tbf
Token bucket filter (bandwidth limiting)delay ms
Add latency to packetsloss percent
Drop percentage of packetsrate bandwidth
Maximum bandwidth rate
INSTALL
sudo apt install iproute2
sudo pacman -S iproute2
sudo apk add iproute2-tc
sudo zypper install iproute2
brew install iproute2
nix profile install nixpkgs#iproute2
CAVEATS
Affects outgoing traffic only. For bidirectional control, configure on both ends. Changes are immediate and can disrupt network connectivity. Not persistent across reboots.
HISTORY
tc is part of iproute2, the Linux networking toolkit, providing advanced traffic shaping and network emulation.