tc

Add constant delay

$ sudo tc qdisc add dev eth0 root netem delay 100ms

$ sudo tc qdisc add dev eth0 root netem delay 100ms 20ms

$ sudo tc qdisc add dev eth0 root netem loss 5%

$ sudo tc qdisc add dev eth0 root tbf rate 10mbit burst 32kbit latency 400ms

$ tc qdisc show dev eth0

$ sudo tc qdisc delete dev eth0

$ sudo tc qdisc change dev eth0 root netem delay 50ms

tc [OPTIONS] OBJECT COMMAND

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.

qdisc

Queuing discipline - manage packet queuing

Add a new traffic control policy

Remove traffic control policy

Modify existing policy

Display current policies

Network emulation (delay, loss, corruption)

Token bucket filter (bandwidth limiting)

Add latency to packets

Drop percentage of packets

Maximum bandwidth rate

Affects outgoing traffic only. For bidirectional control, configure on both ends. Changes are immediate and can disrupt network connectivity. Not persistent across reboots.

tc is part of iproute2, the Linux networking toolkit, providing advanced traffic shaping and network emulation.

ip(8), ethtool(8)