mytcp.tcl

set ns [new Simulator]

set nf [open mytcp.tr w]
$ns trace-all $nf
set np [open mytcp.nam w]
$ns namtrace-all $np

proc finish {} {
global ns nf np 
$ns flush-trace
close $nf
close $np
exec nam mytcp.nam 
exit 0
}

set n0 [$ns node]
set n1 [$ns node]
set n2 [$ns node]
set n3 [$ns node]

$ns duplex-link $n0 $n2 10Mb 10ms DropTail
$ns duplex-link $n1 $n2 10Mb 10ms DropTail
$ns duplex-link $n2 $n3 10Mb 10ms DropTail

$ns queue-limit $n0 $n2 10
$ns queue-limit $n1 $n2 10
$ns queue-limit $n2 $n3 10

$ns duplex-link-op $n0 $n2 orient right-down
$ns duplex-link-op $n1 $n2 orient right-up
$ns duplex-link-op $n2 $n3 orient right


set tcp [new Agent/TCP]
$tcp set class_ 2
$ns attach-agent $n0 $tcp
set sink [new Agent/TCPSink]
$ns attach-agent $n3 $sink
$ns connect $tcp $sink

set ftp [new Application/FTP]
$ftp attach-agent $tcp
$ftp set type_ FTP
$ftp set packet_size_ 1000
$ftp set rate_ 1mb

$ns at 1.0 "$ftp start"
$ns at 3.0 "$ftp stop"

$ns at 5.0 "finish"

$ns run