High Speed Network

set ns [new Simulator]

#Define different colors for data flows (for NAM)
$ns color 1 Blue
$ns color 2 Red

#Open the Trace files
set tracefile1 [open out.tr w]
set winfile [open WinFile w]
$ns trace-all $tracefile1

#open the NAM file
set namefile [open out.nam w]
$ns namtrace-all $namefile

#Define a finish procedure
proc finish {} {
    global ns tracefile1 namefile
    $ns flush-trace
    close $tracefile1
    close $namefile
    exec nam out.nam &
    exit 0
}

#create six nodes
set n0 [$ns node]
set n1 [$ns node]
set n2 [$ns node]
set n3 [$ns node]
set n4 [$ns node]
set n5 [$ns node]

#create links between the nodes
$ns duplex-link $n0 $n2 1024Mb 10ms DropTail
$ns duplex-link $n1 $n2 2Mb 10ms DropTail
$ns simplex-link $n2 $n3 1024Mb 100ms DropTail
$ns simplex-link $n3 $n2 0.3Mb 100ms DropTail
$ns duplex-link $n3 $n4 1024Mb 40ms DropTail
$ns duplex-link $n3 $n5 0.5Mb 30ms DropTail

#Give node position (for NAM)
$ns duplex-link-op $n0 $n2 orient right-down
$ns duplex-link-op $n1 $n2 orient right-up
$ns simplex-link-op $n2 $n3 orient right
$ns simplex-link-op $n3 $n2 orient left
$ns duplex-link-op $n3 $n4 orient right-up
$ns duplex-link-op $n3 $n5 orient right-down

#set Queue Size of link (n2-n3) to 20
$ns queue-limit $n2 $n3 20

#setup a TCP connection
set tcp [new Agent/TCP]
$ns attach-agent $n0 $tcp
set sink [new Agent/TCPSink]
$ns attach-agent $n4 $sink
$ns connect $tcp $sink
$tcp set fid_ 1
$tcp set packetSize_ 552

#Setup a FTP over TCP connection
set ftp [new Application/FTP]
$ftp attach-agent $tcp



$ns at 1.0 "$ftp start"
$ns at 124.0 "$ftp stop"


#procedure for plotting window size. Gets as arguments the name
# of the tcp source code node (called "tcpSource") and of the output file

proc plotWindow {tcpSource file} {
    global ns
    set time 0.1
    set now [$ns now]
    set cwnd [$tcpSource set cwnd_]
    puts $file "$now $cwnd"
    $ns at [expr $now+$time] "plotWindow $tcpSource $file"

}

$ns at 0.1 "plotWindow $tcp $winfile"

$ns at 125.0 "finish"
$ns run