QoS Linux with HFSC

HFSC

HFSC is a method to prioritize traffic with iptables and tc. Make sure your kernel supports HFSC.

I successfully use this script, which brought me dramatically improved latency while up- and downloading simultaneously via a 1024/128 adsl line (in Germany). I tried the same with HTB before, and it didn’t work so well. I use a 2.6.10 kernel image on Debian Linux.


 #!/bin/sh
 #
 # SipShaper v0.01
 # VoIP Traffic Shaper for 1024/128Kbit/s ADSL Line
 #
 # Written by Udo Schacht-Wiegand (2005-04-03) 
 #
 # based on MYSHAPER from Dan Singletary (8/7/02)
 # http://www.nslu2-linux.org/wiki/HowTo/EnableTrafficShaping
 # and on phone-man's script
 # http://www.ip-phone-forum.de/forum/viewtopic.php?p=100371#100371
 # and on the (German) Linux Magazine 02/05 article p.28
 # 
 # Please mail comments and improvements to sipshaper at udo dot comlink dot org
 
 
 # Set your outgoing interface and upload rate (in kbit/s) here
 DEV=ppp0
 RATEUP=128
 
 RTPS=$(cat /etc/asterisk/rtp.conf|awk -F= '/rtpstart/ {print $2}')
 RTPE=$(cat /etc/asterisk/rtp.conf|awk -F= '/rtpend/ {print $2}')

 # Which ports should be prioritized (yes, I know that ssh is not VoIP ;-)
 VOIPPORTS="sip iax $RTPS:$RTPE ssh" 
 
 # Which servers should be prioritized (may be empty "")
 VOIPIPS="192.168.178.1 192.168.178.99"
 
 
 # end of configuration options
 
 ######################
 # show status and exit
 ######################
 
 if [[ "$1" = "status" ]
 then
         echo "[[qdisc]"
         tc -s qdisc show dev $DEV
 
         echo ""
         echo "[[class]"
         tc -s class show dev $DEV
 
         echo ""
         echo "[[filter]"
         tc -s filter show dev $DEV
 
         echo ""
         echo "[[iptables]"
         iptables -t mangle -L SIPSHAPER -v -x 2> /dev/null
         exit
 fi
 
 ######################
 # default: start it  #
 ######################
 
 # Reset everything to a known state (cleared)
 tc qdisc del dev $DEV root    2> /dev/null > /dev/null
 
 # Flush and delete tables
 iptables -t mangle --delete POSTROUTING -o $DEV -j SIPSHAPER 2> /dev/null > /dev/null
 iptables -t mangle --flush        SIPSHAPER 2> /dev/null > /dev/null
 iptables -t mangle --delete-chain SIPSHAPER 2> /dev/null > /dev/null
 
 ######################
 # stop it and exit 
 ######################
 
 if [[ "$1" = "stop" ] 
 then 
         echo "Shaping removed on $DEV."
         exit
 fi
 
 ######################
 # set up shaping
 ######################
 
 # add HFSC root qdisc
 tc qdisc add dev $DEV root handle 1: hfsc default 10
 
 # add main rate limit class
 tc class add dev $DEV parent 1: classid 1:1 hfsc sc rate ${RATEUP}kbit ul rate ${RATEUP}kbit
 
 # keep it simple: two classes only
 tc class add dev $DEV parent 1:1 classid 1:10 hfsc sc umax 1500b dmax 53ms rate 40kbit ul rate ${RATEUP}kbit
 tc class add dev $DEV parent 1:1 classid 1:11 hfsc sc umax 1500b dmax 30ms rate 80kbit ul rate ${RATEUP}kbit
 
 # add SIPSHAPER chain to the mangle table in iptables 
 iptables -t mangle --new-chain SIPSHAPER
 iptables -t mangle --insert POSTROUTING -o $DEV -j SIPSHAPER
 
 # Filter for voip packets
 tc filter add dev $DEV parent 1: prio 1 protocol ip handle 1 fw flowid 1:11 
 
 
 # VoIP ports as defined above
 for port in $VOIPPORTS
 do
         iptables -t mangle -A SIPSHAPER -p udp --sport $port -j MARK --set-mark 1 
         iptables -t mangle -A SIPSHAPER -p udp --dport $port -j MARK --set-mark 1 
 done
 
 # VoIP IPs as defined above 
 for ip in $VOIPIPS
 do
         iptables -t mangle -A SIPSHAPER -p udp --src $ip -j MARK --set-mark 1 
         iptables -t mangle -A SIPSHAPER -p udp --dst $ip -j MARK --set-mark 1 
 done
 
 
 
 echo SipShaper started on $DEV with ${RATEUP}kbit/s upload rate.
 
 echo -n "QoS activated for ports: " 
 for port in $VOIPPORTS
 do
         echo -n " $port"
 done
 echo "."
 
 echo -n "QoS activated for ip#  : "
 for ip in $VOIPIPS
 do
         echo -n " $ip"
 done
 echo "."
 
 #end

Comments are welcome.

QoS Linux with HFSC

HFSC

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