puts "sourcing tcl/lan/vlan.tcl..."source ../lan/vlan.tclset opt(tr)	outset opt(namtr)	"vlantest-flat.nam"set opt(seed)	0set opt(stop)	.5set opt(node)	4set opt(qsize)	100set opt(bw)	10Mbset opt(delay)	1msset opt(ll)	LLset opt(ifq)	Queue/DropTailset opt(mac)	Mac/Csma/Cdset opt(chan)	Channelset opt(tcp)	TCP/Renoset opt(sink)	TCPSinkset opt(app)	FTPproc finish {} {	global ns opt	$ns flush-trace	exec nam $opt(namtr) &	exit 0}proc create-trace {} {	global ns opt	if [file exists $opt(tr)] {		catch "exec rm -f $opt(tr) $opt(tr)-bw [glob $opt(tr).*]"	}	set trfd [open $opt(tr) w]	$ns trace-all $trfd	if {$opt(namtr) != ""} {		$ns namtrace-all [open $opt(namtr) w]	}	return $trfd}proc create-topology {} {	global ns opt	global lan node source node0 nodex	set num $opt(node)	for {set i 0} {$i < $num} {incr i} {		set node($i) [$ns node]		lappend nodelist $node($i)	}	set lan [$ns make-lan $nodelist $opt(bw) \			$opt(delay) $opt(ll) $opt(ifq) $opt(mac) $opt(chan)]	set node0 [$ns node]	$ns duplex-link $node0 $node(1) 20Mb 2ms DropTail	$ns duplex-link-op $node0 $node(1) orient right	set nodex [$ns node]	$ns duplex-link $nodex $node(2) 20Mb 2ms DropTail	$ns duplex-link-op $nodex $node(2) orient left}## MAIN ##set ns [new Simulator]set trfd [create-trace]create-topologyset tcp0 [$ns create-connection TCP/Reno $node0 TCPSink $nodex 0]$tcp0 set window_ 15set ftp0 [$tcp0 attach-app FTP]#set udp0 [new Agent/UDP]#$ns attach-agent $node0 $udp0#set cbr0 [new Application/Traffic/CBR]#$cbr0 attach-agent $udp0#set rcvr0 [new Agent/Null]#$ns attach-agent $nodex $rcvr0#$udp0 set dst_ [$rcvr0 set addr_]$ns at 0.0 "$ftp0 start"#$ns at 0.0 "$cbr0 start"$ns at $opt(stop) "finish"$ns run