A Sample TCL

1
A Sample TCL

• July 20, 2005

2

• Create a simulator object
• set ns new Simulator
• ns use-newtrace
• Open the ns trace file
• set nf open out.ns w
• ns trace-all nf
• set thru(0) open thru0.tr w
• set thru(1) open thru1.tr w
• set cw open cw.tr w
• set val(stop) 200 time of simulation end
• set val(nn) 8 number of nodes
• proc stop
• global ns nf thru cw
• ns flush-trace
• close nf
• close thru(0)

3

• Create 8 nodes
• for set i 0 i lt val(nn) incr i
• set n(i) ns node
• Create a duplex link between the nodes
• ns duplex-link n(0) n(2) 100Mb 10ms DropTail
• ns duplex-link n(2) n(4) 100Mb 10ms DropTail
• ns duplex-link n(1) n(3) 100Mb 10ms DropTail
• ns duplex-link n(3) n(4) 100Mb 10ms DropTail
• ns duplex-link n(4) n(5) 1Mb 10ms DropTail
• ns duplex-link n(5) n(6) 100Mb 10ms DropTail
• ns duplex-link n(5) n(7) 100Mb 10ms DropTail

4

• Create a TCP agent and attach it to node n0
• set src_tcp new Agent/TCP/Newreno
• ns attach-agent n(0) src_tcp
• set dst_tcp new Agent/TCPSink/DelAck
• ns attach-agent n(6) dst_tcp
• ns connect src_tcp dst_tcp
• src_tcp set maxcwnd_ 32
• Tahoe new Agent/TCP
• Reno new Agent/TCP/Reno
• New reno new Agent/TCP/Newreno
• Vegas new Agent/TCP/Vegas

5

• Setup a FTP over TCP connection
• set ftp new Application/FTP
• ftp attach-agent src_tcp
• ftp set packetSize_ 512

6

• UDP flow between n1 and n7
• set src_udp new Agent/UDP
• ns attach-agent n(1) src_udp
• set dst_udp new Agent/LossMonitor
• ns attach-agent n(7) dst_udp
• ns connect src_udp dst_udp

7

• Setup a CBR over UDP connection
• set cbr new Application/Traffic/CBR
• cbr attach-agent src_udp
• cbr set type_ CBR
• cbr set packetSize_ 512
• cbr set rate_ 4Mb
• 200kbps cbr set rate_ 0.2Mb
• 400kbps cbr set rate_ 0.4Mb
• 4Mbps

8

• printing throughput of each client and channel
  utilization
• set last_udp 0.0
• set last_tcp 0.0
• proc plotThru
• global ns thru last_udp last_tcp dst_udp
  dst_tcp val
• set time 1
• set now ns now
• set total 0.0
• set cur_tcp dst_tcp set bytes_
• set bytesthru expr cur_tcp-last_tcp
• set bitsthru expr bytesthru8.0/1000000.0/
  time
• puts thru(0) "format .2f now format
  .2f bitsthru"
• set total expr totaltemp
• set cur_udp dst_udp set bytes_
• set bytesthru expr cur_udp-last_udp

9

• proc plotCW
• global ns cw src_tcp val
• set time 1
• set now ns now
• set cwnd src_tcp set cwnd_
• puts cw "now cwnd"
• Your work here
• ns at 0.1 "plotCW"

10

• proc summary
• global ns val dst_udp dst_tcp
• set tcpbytes dct_tcp set bytes_
• .. (get bytes for udp
• .. Get ratio between TCP and UDP. (converges
  the nominator to float number by 1.0)
• average bandwidth for TCP (make sure
  converges it to bits)
• puts

11

• ns at 0.0 "ftp start"
• ns at 0.0 "cbr start"
• ns at val(stop) "ftp stop"
• ns at val(stop) "cbr stop"
• ns at val(stop) "stop"
• ns at expr val(stop) - 0.01 summary"
• Run the simulation
• ns run

12
How to plot the results

• Trace format
• Time thru
• 0.10 0.06
• 1.10 0.98

13
Gnuplot

• set ylabel Throughput (Mbps)
• set xlabel Time
• set term postscript color
• Set output thru.eps
• plot ./thru0.tr using 12 title TCP with
  linespoints 1, ./thru1.tr using 12 title UDP
  with linespoints 2
• Save it to xxx.plt
• Excute it using gnuplot xxx.plt

14
(No Transcript)
15

• set ylabel Congestion Window
• set xlabel Time
• set term postscript color
• set output cw.eps
• plot ./cw.tr using 12 title Congestion
  Window Size with linespoints 1
• Save it to xxx.plt
• Excute it using gnuplot xxx.plt

16
(No Transcript)
17
How to include pics into one page

• Using Latex
• \documentclassarticle\usepackagegraphics
  \begindocument\beginfigure \begincenter
  \begintabularcc \resizebox60mm!\
  includegraphicscw.eps
  \resizebox60mm!\includegraphicsthru.eps
  \\ \resizebox60mm!\includegraphicscw.e
  ps \resizebox60mm!\includegraphics
  thru.eps \\ \endtabular \captionThis
  is sample figures. \labeltest4
  \endcenter\endfigure\enddocument
• Save it to xxx.tex
• Complie it using latex xxx.tex
• dvips o xxx.ps
  xxx.dvi

18
(No Transcript)