set ns [new Simulator]

proc finish {} {
	exit 0
}

set n0 [$ns node]
set n1 [$ns node]

$ns duplex-link $n0 $n1 1Mb 10ms DropTail


for {set i 0 } { $i < 20 } { incr i } {      set pareto11($i) [ new Application/Traffic/Pareto ]      $pareto11($i) set rate_ 1Mb      set udp11($i) [ new Agent/UDP ]      $ns attach-agent $n0 $udp11($i)      $pareto11($i) attach-agent $udp11($i)    }set null12 [ new Agent/Null ] $ns attach-agent $n1 $null12for {set i 0 } { $i < 20 } { incr i } {      $ns connect $udp11($i) $null12    }for {set i 0 } { $i < 20 } { incr i } {      $ns at 20 "$pareto11($i) start"      $ns at 80 "$pareto11($i) stop"    }

set udp0 [new Agent/UDP]
$ns attach-agent $n0 $udp0

set cbr0 [new Application/Traffic/CBR]
$cbr0 set packetSize_ 100
$cbr0 set rate_ 0.9Mb
$cbr0 attach-agent $udp0

set null0 [new Agent/Null]
$ns attach-agent $n1 $null0

$ns connect $udp0 $null0
set ping0 [new Agent/PingReq]
set ping1 [new Agent/PingReq]
$ns attach-agent $n0 $ping0
$ns attach-agent $n1 $ping1

$ns connect $ping0 $ping1
$ping0 recordfile RTT_data
$ping0 lossfile loss_data
$ns at 0 "$cbr0 start"
$ns at 0 "$ping0 start"
$ns at 80 "$cbr0 stop"
$ns at 100 "$ping0 report"

$ns at 100.0 "finish"
$ns run