Simulate limited bandwidth / latency on localhost

netdelay.sh

#!/bin/bash

set -euo pipefail

bandwidth="1000mbit"
latency="200ms"
jitter="50ms"
correlation="25%"

case "$1" in
  start)
    sudo tc qdisc del dev lo root 2> /dev/null || true
    sudo tc qdisc add dev lo root netem delay ${latency} ${jitter} ${correlation} rate ${bandwidth}
  ;;

  stop)
    sudo tc qdisc del dev lo root
  ;;

  status)
    tc -s qdisc ls dev lo
  ;;

  *)
    echo "usage: $0 <start|stop|status>"
  ;;
esac