source  /nsallinone/ns-2/tcl/lib/ns-default.tcl

set ns [new Simulator]
set n0 [$ns node]
set r1 [$ns node]
set r2 [$ns node]
set n1 [$ns node]

set f [open out.tr w]
$ns trace-all $f

$ns duplex-link $n0 $r1 10Mb 1ms DropTail 
$ns simplex-link $r1 $r2 10Mb 280ms DropTail
$ns simplex-link $r2 $r1 28.8Kb 280ms DropTail
$ns duplex-link $r2 $n1 10Mb 1ms DropTail

set src [new Agent/TCP/FullTcp]
set sink [new Agent/TCP/FullTcp]
$ns attach-agent $n0 $src
$ns attach-agent $n1 $sink

$ns connect $src $sink

# set up TCP-level connections
$sink listen ; # will figure out who its peer is
$src set packetSize 530
$src set tcpTick 0.1
$src set window_ 100
$sink set window_ 100

set ftp1 [$src attach-app FTP]
$ns at 0.0 "$ftp1 produce 1887"

$ns at 100.0 "$src close"

$ns run