1. Run ns-2
2. ns-2 General
3. ns-2 Topology/Traffic
4. Tcl General
5. Tcl Command
6. Tcl Keyword

Run ns-2

• run ns in text mode
  $ns tcl/ex/mcast.tcl

• Edit tcl file
  simple.tcl:
        set ns [new Simulator]
        $ns at 1 "puts \"Hello World!\""
        $ns at 1.5 "exit"
        $ns run
  [prompt]$ns simple.tcl
  Hello World!
  

• run ns with nam
  1. (run XWin32 in Windows, it may be very difficult to run Cygwin X server)
     
  2. run Cygwin
  3. $export DISPLAY=TRINITY:0.0 (TRINITY -> local host name, should be UPPER CASE LETTER!!)
     
  4. $ns tcl/ex/nam-example.tcl

ns-2 General

• NAM : node/link position/color, tracing
• scheduling event : $ns at time event
  $ns at 0.1 "$cbr start"
  
• flush-trace : dump the traces on the respective files
• How to work with trace files: awk, grep, perl, tcl script
• How to plot: gnuplot, xgraph

ns-2 Topology/Traffic

• define node : set n0 [$ns node]
• define link : $ns duplex-link $n0 $n2 10Mb 10ms DropTail
• define queue : $ns queue-limit $n0 $n2 20 (default value : 50)

• setup a UDP connection : set udp [new Agent/UDP]; $ns attach-agent $n1 $udp
• setup a CBR over UDP connection : set cbr [new Application/Traffic/CBR]; $cbr attach-agent $udp; $cbr set packetSize_ 1000; $cbr set rate_ 0.01Mb; $cbr set random_ false

Tcl General

• # : commented line
• create a file and assign a pointer to it : set file_p [open filename w]
• exec : execution of a unix command
• Simulator : Simulator class

Tcl Command

• set : assign a value to a variable
  set a 43 ; a = 43
  set x $a ; x = a
  
• expr : mathematical operation
  set x [expr $a + $b]; x = a + b
  
• puts : printing an output
  puts "[expr 1.0/60.0]"
  puts $file_p "text" ; writing to a file
  
• exit 0 : ends the application and the number 0 means a clean exit.
• if { expression } {
  -execute some commands-
  } else {
  -execute some commands-
  }
  
• for {set i 0} {$i < 5} { incr i } {
  - execute some commands -
  }
  
• proc procname { par1 par2 ... } {
        global var1 var2
        -commands-
        return $something
  }
  

Tcl Keyword

• Class : used to declare a class
• new : instantiation of a class
• instproc : the methods of the classes are declared by
• init : constructor of the class
• self : a pointer to the object itself
• instvar : to declare the instance variable, The data members of a specific class are only defined within the member functions of the class. This is unlike C++ in which the data members of the class are specfied in advance, and typically in header files. Class data members are created or references using the instvar directive.
• -superclass : used for declaring that a class inherits from another one
• global : used to tell we are using the variables declared outside the procedures

For every simulator,

1. how to install
2. how to run (run and analyze a typical example)
3. how to write a simulation
4. how to analyze
5. That's all !!