NetExp

set ns [new Simulator]
$ns rtproto Session
set f [open tes.tr w]
set nf [open tes.nam w]

$ns namtrace-all $nf
$ns trace-all $f

proc finish { } {
    global ns f
    $ns flush-trace
    close $f
    exec nam tes.nam &
    exit 0
}

set n0 [$ns node]
$n0 color "Blue"
set n1 [$ns node]
$n1 color "Green"
set n2 [$ns node]
$n2 color "Yellow"
set n3 [$ns node]

$ns color 1 "Green"
$ns color 2 "Red"

$ns duplex-link $n0 $n1 10mb 10ms DropTail
$ns duplex-link $n1 $n2 10Mb 10ms DropTail
$ns duplex-link $n2 $n3 10Mb 10ms DropTail
$ns duplex-link $n3 $n0 10Mb 100ms DropTail


$ns duplex-link-op $n0 $n1 color "Red"
#TCP
set tcp [new Agent/TCP]
$ns attach-agent $n0 $tcp


#Sink
set sink [new Agent/TCPSink]
$ns attach-agent $n1 $sink

$ns connect $tcp $sink
$tcp set fid_ 1
$tcp set packetSize_ 1024

#FTP
set ftp [new Application/FTP]
$ftp attach-agent $tcp

#dosen't varry
$ftp set rate_ 0.001mb


#udp
set udp [new Agent/UDP]
$ns attach-agent $n2 $udp

#null
set null [new Agent/Null]
$ns attach-agent $n0 $null

#connection
$ns connect $udp $null
$udp set fid_ 2

#CBR
set cbr [new Application/Traffic/CBR]
$cbr attach-agent $udp
$cbr set packetSize_ 1024
$cbr set rate_ 5mb



#$ns at 0 "$ftp start"
$ns at 0 "$cbr start"
$ns rtmodel-at 2 down $n1 $n0
$ns at 10 "finish"
$ns run