set ns [new Simulator]
set tracef [open example1.tr w]
$ns trace-all $tracef
set namtf [open example1.nam w]
$ns namtrace-all $namtf
proc finish {} {
global ns tracef namtf
$ns flush-trace
close $tracef
close $namtf
exec nam example1.nam &
exit 0
}
set n0 [$ns node]
set n1 [$ns node]
$ns duplex-link $n0 $n1 1Mb 10ms DropTail
set udp0 [new Agent/UDP]
$ns attach-agent $n0 $udp0
set cbr0 [new Application/Traffic/CBR]
$cbr0 set packetSize_ 500
$cbr0 set interval_ 0.5
$cbr0 set attach-agent $udp0
set null0 [new Agent/Null]
$ns attach-agent $n1 $null0
$ns connect $udp0 $null0
$ns at 0.5 "$cbr0 start"
$ns at 4.5 "$cbr0 stop"
$ns at 5.0 "finish"
$ns run

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