TCL 3rd class

set ns [new Simulator]
set f [open out.tr w]
set nf [open output.nam w]
$ns namtrace-all $nf
$ns trace-all $f
$ns color 1 Blue
$ns color 2 Red
proc finish { } {
    global ns f
    $ns flush-trace
    close $f
    exec nam output.nam &
    exit 0
    }
set n0 [$ns node]
set n1 [$ns node]
set n2 [$ns node]
set n3 [$ns node]
set n4 [$ns node]
set n5 [$ns node]
set n6 [$ns node]

$n0 color red
$n1 color blue
$n2 color green
$n3 color yellow
$n4 color cyan
$n5 color magenta
$n6 color orange

$ns duplex-link $n0 $n1 1mb 10ms DropTail
$ns duplex-link $n2 $n4 1mb 10ms DropTail
$ns duplex-link $n3 $n5 1mb 10ms DropTail
$ns simplex-link $n4 $n6 5mb 10ms DropTail

$ns duplex-link $n0 $n6 1mb 10ms DropTail
$ns duplex-link $n1 $n4 1mb 10ms DropTail
$ns duplex-link $n0 $n5 1mb 10ms DropTail
$ns duplex-link $n1 $n3 1mb 10ms DropTail
$ns duplex-link $n2 $n6 1mb 10ms DropTail

$ns at 5.0 "finish"
$ns run