5Node Star Topology

set ns [new Simulator]
set tracefile [open lab2.tr w]
$ns trace-all $tracefile
set namfile [open lab2.nam w]
$ns namtrace-all $namfile
set n0[$ns node]
set n1[$ns node]
set n2[$ns node]
set n3[$ns node]
set n4[$ns node]
$ns duplex-link $n0 $n4 1Mb 10ms DropTail
$ns duplex-link $n1 $n4 1Mb 10ms DropTail
$ns duplex-link $n4 $n3 1Mb 10ms DropTail
$ns duplex-link $n4 $n2 1Mb 10ms DropTail
set tcp [new Agent/TCP]
$ns attach-agent $n0 $tcp
set sink [new Agent/TCPSink]
$ns attach-agent $n3 $sink
$ns connect $tcp $sink
set ftp [new Application/FTP]
$ftp attach-agent $tcp
set udp [new Agent/UDP]
$ns atatch-agent $1 $udp
set null [new Agent/NULL]
$ns attach-agent $2 $null
$ns connect $udp $null
set cbr [new Application/Traffic/CBR]
$cbr set packetSize_ 500
$cbr set interval_ 0.005
$cbr attach-agent $udp
$ns at 0.0 "$cbr start"
$ns at 0.0 "$ftp start"
$ns at 9.0 "$cbr stop"
$ns at 9.0 "$ftp stop"
proc finish {} {
global ns namfile tracefile
$ns flush-trace
close $tracefile
close $namfile
exec nam lab1.nam &
exit 0
}
$ns at 10.0 "finish"
$ns run