proc create_topology {} {
global ns n num_node link qmon p dst src link test_node


set num_node 28
set test_node [expr $num_node - 1]

for {set i 0} {$i < $num_node} {incr i} {
    set n($i) [$ns node]
}

$ns duplex-link $n(0) $n(1) 1.5Mb 100ms DropTail
$ns queue-limit $n(1) $n(0) 10
$ns duplex-link $n(1) $n(2) 10Mb 1ms DropTail

for {set i 3} {$i < $test_node} {incr i} {
    $ns duplex-link $n(0) $n($i) 10Mb 1ms DropTail
    set dst($i) [new Agent/TCPSink]
    $ns attach-agent $n($i) $dst($i)
    set src($i) [new Agent/TCP/Vegas]
  #  $src($i) set windowInitOption_ 1
    $src($i) set fid_ $i
    $src($i) set packetSize_ 576
    $ns attach-agent $n(2) $src($i)
    $ns connect $src($i) $dst($i)
    set p($i) [new Application/Traffic/Pareto]
    $p($i) attach-agent $src($i)
   
    $p($i) set burst_time_ 500ms
    $p($i) set idel_time_ 500ms
    $p($i) set burstlen_ 50
    $p($i) set shape_ 1.5
}
$ns duplex-link $n(0) $n($test_node) 1Mb 20ms DropTail
set dst($test_node) [new Agent/TCPSink]
set src($test_node) [new Agent/TCP/Reno]
$ns attach-agent $n($test_node) $dst($test_node)
$ns attach-agent $n(2) $src($test_node) 
$ns connect $dst($test_node) $src($test_node)
$src($test_node) set packetSize_ 576
$src($test_node) set fid_ $test_node

}


set ns [new Simulator]

# set up colors for nam 
for {set i 1} {$i <= 30} {incr i} {
    set color [expr $i % 6]
    if {$color == 0} {
	$ns color $i blue
    } elseif {$color == 1} {
	$ns color $i red
    } elseif {$color == 2} {
	$ns color $i green
    } elseif {$color == 3} {
	$ns color $i yellow
    } elseif {$color == 4} {
	$ns color $i brown
    } elseif {$color == 5} {
	$ns color $i black
    }
}

# Create nam trace and generic packet trace
#$ns namtrace-all [open validate.nam w]
# trace-all is the generic trace we've been using


$ns trace-all [open /tmp/validate.out w]
create_topology

proc open_trace { stop_time} {
    global ns trace_file_ n link src test_node

   $src($test_node) advanceby 50

}

for { set i 3 } { $i < $test_node } { incr i } {
    $ns at 0.0 "$p($i) start"
}

$ns at 500 "finish"

proc finish {} {
	global ns qmon dst test_node
	$ns flush-trace
    
	puts "running nam..."
#	exec nam validate.nam &

	exit 0
}

# Start the simualtion
$ns run