set ns [new Simulator]
set nf [open lab1.nam w]
$ns nametrace-all $nf
#Part 2 exercise section
set f [open lab1.tr w]

proc record(){
    global sink f
    set ns [Simulator instance]
    set time 0.15
    set bw [$sink set bytes_]
    set now [$ns now]
    puts $f "$now [expr (($bw/$time)*8)/1000000)]"
    $sink set bytes_ 0
    $ns at [expr $now + $time] "record"
}
#Part 2 end
proc finish(){
    global ns nf f
    $ns flush-trace
    close $nf
    close $f
    exit 0
}

#Node creations

set n0 [$ns node]
set n1 [$ns node]
$ns duplex-link $n0 $n1
#Transmitting agent
set udp0 [new Agent/UDP]
$udp0 set packetSize_ 1200
$ns attach-agent $n0 $udp0
#Transmittion
set traffic0 [new Application/Traffic/CBR]
$traffic0 set packetSize_ 1200
$traffic0 set interval_ 0.01
$traffic attach-agent $udp0
#Sink agent ( reciever )
set sink [new Agent/LossMonitor]
$ns attach-agent $n1 $sink
#Agent relation
$ns connect $udp0 $sink

#Record initiation
$ns at 0.0 "record"
#Traffic initiation
$ns at 2.0 "$traffic0 start"
$ns at 13.0 "$traffic0 stop"
#Script termination / call to finish() function
$ns at 15.0 "finish"
$ns run