Friday, September 17, 2010

Using tc to regulate uplink speed

Here is a nice script that I found:


# tc uses the following units when passed as a parameter.
# kbps: Kilobytes per second
# mbps: Megabytes per second
# kbit: Kilobits per second
# mbit: Megabits per second
# bps: Bytes per second
# Amounts of data can be specified in:
# kb or k: Kilobytes
# mb or m: Megabytes
# mbit: Megabits
# kbit: Kilobits
# To get the byte figure from bits, divide the number by 8 bit

#Name of the traffic control command.

# The network interface we're planning on limiting bandwidth.
IF=eth0 # Interface

# Download limit (in mega bits)
DNLD=1mbit # DOWNLOAD Limit

# Upload limit (in mega bits)
UPLD=1mbit # UPLOAD Limit

# IP address of the machine we are controlling
IP= # Host IP

# Filter options for limiting the intended interface.
U32="$TC filter add dev $IF protocol ip parent 1:0 prio 1 u32"

start() {

# We'll use Hierarchical Token Bucket (HTB) to shape bandwidth.
# For detailed configuration options, please consult Linux man
# page.

$TC qdisc add dev $IF root handle 1: htb default 30
$TC class add dev $IF parent 1: classid 1:1 htb rate $DNLD
$TC class add dev $IF parent 1: classid 1:2 htb rate $UPLD
$U32 match ip dst $IP/32 flowid 1:1
$U32 match ip src $IP/32 flowid 1:2

# The first line creates the root qdisc, and the next two lines
# create two child qdisc that are to be used to shape download
# and upload bandwidth.
# The 4th and 5th line creates the filter to match the interface.
# The 'dst' IP address is used to limit download speed, and the
# 'src' IP address is used to limit upload speed.


stop() {

# Stop the bandwidth shaping.
$TC qdisc del dev $IF root


restart() {

# Self-explanatory.
sleep 1


show() {

# Display status of traffic control status.
$TC -s qdisc ls dev $IF


case "$1" in


echo -n "Starting bandwidth shaping: "
echo "done"


echo -n "Stopping bandwidth shaping: "
echo "done"


echo -n "Restarting bandwidth shaping: "
echo "done"


echo "Bandwidth shaping status for $IF:"
echo ""


echo "Usage: tc.bash {start|stop|restart|show}"

esac exit 0

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