red1.tcl

This a script for 3 TCP connections with a RED bottleneck buffer. Parameters are configured automati

set ns [new Simulator]

set nf [open out.nam w]
$ns namtrace-all $nf    

set tf [open out.tr w]
set windowVsTime [open win w]
set param [open parameters w]
$ns trace-all $tf


#Define a 'finish' procedure
proc finish {} {
        global ns nf tf
        $ns flush-trace
        close $nf                   
        close $tf
        exec nam out.nam &               
	exec grep  "a" red-queue.tr > ave.tr
	exec grep  "Q" red-queue.tr > cur.tr
        exit 0
}

#Create bottleneck and dest nodes
set n2 [$ns node]
set n3 [$ns node]

#Create links between these nodes
$ns duplex-link $n2 $n3 0.7Mb 20ms RED

set NumbSrc 3
set Duration 50

#Source nodes
for {set j 1} {$j<=$NumbSrc} { incr j } {
set S($j) [$ns node]
}                

# Create a random generator for starting the ftp and for bottleneck link delays
set rng [new RNG]
$rng seed 2

# parameters for random variables for begenning of ftp connections 
set RVstart [new RandomVariable/Uniform]
$RVstart set min_ 0
$RVstart set max_ 7
$RVstart use-rng $rng   

#We define random starting time for each connection
for {set i 1} {$i<=$NumbSrc} { incr i } {
set startT($i)  [expr [$RVstart value]]
set dly($i) 1
puts $param "startT($i)  $startT($i) sec"
}

#Links between source and bottleneck
for {set j 1} {$j<=$NumbSrc} { incr j } {
$ns duplex-link $S($j) $n2 10Mb $dly($j)ms DropTail
$ns queue-limit $S($j) $n2 20
}                         

#Set Queue Size of link (n2-n3) to 100
$ns queue-limit $n2 $n3 100

set redq [[$ns link $n2 $n3] queue]
set traceq [open red-queue.tr w]
$redq trace curq_
$redq trace ave_
$redq attach $traceq

#TCP Sources
for {set j 1} {$j<=$NumbSrc} { incr j } {
set tcp_src($j) [new Agent/TCP/Reno]
$tcp_src($j) set window_ 8000
} 

#TCP Destinations
for {set j 1} {$j<=$NumbSrc} { incr j } {
set tcp_snk($j) [new Agent/TCPSink]
}  

#Connections
for {set j 1} {$j<=$NumbSrc} { incr j } {
$ns attach-agent $S($j) $tcp_src($j)
$ns attach-agent $n3 $tcp_snk($j)
$ns connect $tcp_src($j) $tcp_snk($j)
}  

#FTP sources
for {set j 1} {$j<=$NumbSrc} { incr j } {
set ftp($j) [$tcp_src($j) attach-source FTP]
}       

#Parametrisation of TCP sources
for {set j 1} {$j<=$NumbSrc} { incr j } {
$tcp_src($j) set packetSize_ 552
}                   

#Schedule events for the FTP agents:
for {set i 1} {$i<=$NumbSrc} { incr i } {
$ns at $startT($i) "$ftp($i) start"
$ns at $Duration "$ftp($i) stop"
}                    

proc plotWindow {tcpSource file k} {
global ns NumbSrc
set time 0.03
set now [$ns now]
set cwnd [$tcpSource set cwnd_]
if {$k == 1} {
   puts -nonewline $file "$now \t $cwnd \t" 
  } else { 
   if {$k < $NumbSrc } { 
   puts -nonewline $file "$cwnd \t" } 
}
if { $k == $NumbSrc } {
   puts -nonewline $file "$cwnd \n" }
$ns at [expr $now+$time] "plotWindow $tcpSource $file $k" }

# The procedure will now be called for all tcp sources
for {set j 1} {$j<=$NumbSrc} { incr j } {
$ns at 0.1 "plotWindow $tcp_src($j) $windowVsTime $j" 
}

$ns at [expr $Duration] "finish"
$ns run