DCE Cradle Use-case 1

This tutorial document describes what DCE Cradle is, how we can use it, how we extend it.

Team:

Hajime Tazaki, Frederic Urbani, Thierry Turletti

Key Result(s):

TCP goodput performance in DCE Cradle shows similar results with real network configuration and software on Linux.

Source(s):

The paper describing this text was submitted to Workshop on ns-3 2013 (under review).

Contacts:

Hajime Tazaki (tazaki at nict.go.jp)

Introduction:

DCE Cradle allows us to use ns-3 native application with Linux kerne as a network stack. The key question is: how different/similar DCE Cradle behaves ? This tutorial tries to answer this question with showing TCP goodput performance.

Methods:

We need to prepare the following simulation codes to conduct the experiment.

• ns-3-dev
• ns-3-dce
• ns-3-linux
• Network Simulation Cradle (NSC)
• DCE Cradle patch
• iperf
• Linux TC (packet loss and delay injection)

Results:

While the experimentation with ns-3 native TCP stack shows about 83% less bandwidth than with the real environment, NSC and DCE Cradle obtain more realistic performance (only 25-30% less bandwidth than with the real environment) under the simple dumbbel topology scenario.

(News) If we changed the default variables of ns-3 TCP stack as follows, the result of goodput has improved.

Config::SetDefault ("ns3::TcpSocket::SegmentSize", UintegerValue (1448));
Config::SetDefault ("ns3::TcpSocket::DelAckCount", UintegerValue (1));

Instructions to Replicate This Experiment:

1. Experiment on ns-3

   1. Setup ns-3-dce

      % mkdir dce-cradle-test
      % cd dce-cradle-test
      % hg clone -r 327 http://code.nsnam.org/furbani/ns-3-dce
      % ./utils/clone_and_compile_ns3_dce.sh

      for more information, see the DCE documentation.

   2. patch DCE Cradle extension

      % cd dce-cradle-test
      % wget https://codereview.appspot.com/download/issue6856090_7001.diff
      % cd ns-3-dce
      % patch -p1 < ../issue6856090_7001.diff
      % ./waf
      % ./waf install

   3. prepare Network Simulation Cradle

      % cd dce-cradle-test
      % wget http://research.wand.net.nz/software/nsc/nsc-0.5.3.tar.bz2
      % tar xfj nsc-0.5.3.tar.bz2
      % mv nsc-0.5.3 nsc
      % cd nsc
      % ./scons.py
      % cp lib/liblinux2.6.26.so ../build/lib/
      % cd ..
      % cd ns-3-dev
      % /waf configure --prefix=`pwd`/../build --with-nsc=../nsc
      % ./waf
      % ./waf install

   4. run a script

      #!/bin/sh
      OUTPUT="output/`date \"+%y%m%d_%H%M\"`"
      mkdir -p ${OUTPUT}
      TRIAL="`seq 1 100`"
      TRIAL_TIME="`seq 1 5`"
      NODES="`seq 1 2 100`"
      DURATIONS="`seq 10 10 400`"
      STACKS="dce dce-linux3 ns3 nsc-linux dce-dccp dce-dccp3"
      PCAP=""
      
      for stack in $STACKS
      do
      for trial in $TRIAL
      do
      if [ $trial -eq 1 ] ; then
      PCAP="--enablePcap=1"
      else
      PCAP="--enablePcap=0"
      fi
      
      echo -n "$stack $trial " >>$OUTPUT/goodput.txt
      NS_ATTRIBUTE_DEFAULT='ns3::TaskManager::FiberManagerType=UcontextFiberManager' ./build/bin/dce-runner ./build/bin/dce-tcp-ns3-nsc-comparison --stack=$stack --seed=$trial ${PCAP} --stopTime=64 | awk '{print $6}' | sed s/\(// >> $OUTPUT/goodput.txt
      done
      
      done
      

2. Experiment on Linux real network

   1. prepare dumbbell topology

      node1              node5
          \              /
         node3 ======== node4
          /              \
      node2              node6

   2. configure bottleneck link

      at node3, packet loss and delay are configured with tc.

      sudo tc qdisc add dev eth0 root handle 1:0 tbf limit 15Kb buffer 10Kb/8 rate 2Mbit
      sudo tc qdisc add dev eth0 parent 1:0 handle 10: netem delay 100ms loss 5%
      sudo sysctl -w net.ipv4.ip_forward=1

      at node4, packet loss and delay are configured with tc as well.

      sudo tc qdisc add dev eth0 root handle 1:0 tbf limit 15Kb buffer 10Kb/8 rate 2Mbit
      sudo tc qdisc add dev eth0 parent 1:0 handle 10: netem delay 100ms loss 5%
      sudo sysctl -w net.ipv4.ip_forward=1

   3. run a script at node1

      TRIAL="`seq 1 100`"
      OUTPUT="output/`date \"+%y%m%d_%H%M\"`"
      
      mkdir -p ${OUTPUT}
      
      # TCP test
      ssh -f 192.168.39.5 iperf -s -p 5001 > /dev/null
      ssh -f 192.168.39.6 iperf -s -p 5001 > /dev/null
      
      
      for trial in $TRIAL
      do
      
      # for tcp
      stack="tcp-linux"
      echo -n "$stack $trial " >>$OUTPUT/goodput.txt
      ssh 192.168.39.1 iperf -p 5001 -c 10.2.0.2  -t 60 -l 1024 -x MS -y c  | cut -d ',' -f 9 >> $OUTPUT/
      goodput.txt &
      ssh 192.168.39.2 iperf -p 5001 -c 10.2.1.2  -t 60 -l 1024 -x MS -y c > /dev/null  &
      wait
      wait
      
      done
      
      
      
      ssh -f 192.168.39.5 pkill iperf
      
      ssh -f 192.168.39.6 pkill iperf
      

3. Plot the results of above experiment

   1. run a script

      You can gather the text outputs from the above experiments and plot the figure with gnuplot.

      #!/bin/bash
      
      #set -x
      OUTPUT=$1
      
      mkdir -p ${OUTPUT}
      
      TRIAL="`seq 1 100`"
      STACKS="dce dce-linux3 ns3 nsc-linux"
      
      # for Stack - Kbps (TCP)
      cat ${OUTPUT}/goodput.txt | dbcoldefine exp seed bps |dbmultistats -k exp bps |dbcol exp mean stddev | grep -v dccp > ${OUTPUT}/goodput.dat
      cat ${OUTPUT}/121120_1701/goodput.txt | dbcoldefine exp seed bps |dbmultistats -k exp bps |dbcol exp mean stddev | grep -v dccp >> ${OUTPUT}/goodput.dat
      
      gnuplot  << EndGNUPLOT
      set ylabel "Goodput (kbps)"
      set terminal postscript eps lw 3 "Helvetica" 24
      set output "${OUTPUT}/goodput.eps"
      set xrange [-1:5]
      set xtics font "Helvetica,14"
      set xtics ("1) DCE\ncradle" 0,  "2) DCE cradle\n(Linux3)" 1, "3) ns-3" 2, "4) NSC Linux" 3, "5) Linux\n2.6.32-28" 4)
      set style fill pattern
      set boxwidth 0.5
      set pointsize 2
      set xzeroaxis
      set grid ytics
      
      plot \
              '${OUTPUT}/goodput.dat' usi :(\$2/1000):(\$3/1000) notitle w boxerrorbars
      
      set terminal png lw 3 16
      set xtics nomirror rotate by -45 font ",16"
      set output "${OUTPUT}/goodput-dce-cradle-tcp.png"
      replot
      
      quit
      EndGNUPLOT