set ns new Simulator
#Define different colors for data flows (for NAM) $ns color 1 Blue $ns color 2 Red
#Open the Trace file set file1 open out.tr w $ns trace-all $file1
#Open the NAM trace file set file2 open out.nam w $ns namtrace-all $file2
#Define a 'finish' procedure proc finish {} {
global ns file1 file2
$ns flush-trace
close $file1
close $file2
exec nam out.nam &
exit 0}
# Next line should be commented out to have the static routing $ns rtproto DV
#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 $n1 0.3Mb 10ms DropTail $ns duplex-link $n1 $n2 0.3Mb 10ms DropTail $ns duplex-link $n2 $n3 0.3Mb 10ms DropTail $ns duplex-link $n1 $n4 0.3Mb 10ms DropTail $ns duplex-link $n3 $n5 0.5Mb 10ms DropTail $ns duplex-link $n4 $n5 0.5Mb 10ms DropTail
#Give node position (for NAM) $ns duplex-link-op $n0 $n1 orient right $ns duplex-link-op $n1 $n2 orient right $ns duplex-link-op $n2 $n3 orient up $ns duplex-link-op $n1 $n4 orient up-left $ns duplex-link-op $n3 $n5 orient left-up $ns duplex-link-op $n4 $n5 orient right-up
#Setup a TCP connection set tcp new Agent/TCP/Newreno $ns attach-agent $n0 $tcp set sink new Agent/TCPSink/DelAck $ns attach-agent $n5 $sink $ns connect $tcp $sink $tcp set fid_ 1
#Setup a FTP over TCP connection set ftp new Application/FTP $ftp attach-agent $tcp $ftp set type_ FTP
$ns rtmodel-at 1.0 down $n1 $n4 $ns rtmodel-at 4.5 up $n1 $n4
$ns at 0.1 "$ftp start"
$ns at 6.0 "finish"
$ns run
your script