NS-2

simple.tcl

set ns [new Simulator]

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

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

$ns duplex-link $n0 $n1 5Mb 2ms DropTail

set udp0 [new Agent/UDP]
$ns attach-agent $n0 $udp0
set cbr0 [new Application/Traffic/CBR]
$cbr0 attach-agent $udp0

set null0 [new Agent/Null]
$ns attach-agent $n1 $null0

$ns connect $udp0 $null0

$ns at 1.0 "$cbr0 start"
$ns at 3.0 "finish"

proc finish {} {
        global ns f nf
        $ns flush-trace
        close $f
        close $nf

        puts "running nam..."
        exec nam out.nam &
        exit 0
}

$ns run

ns simple.tcl

ns simple.tcl