Next we need to paste the below code to the Main.tcl file and save the file in the ns-2.35 folder.

Code:

set ns [new Simulator]

set nf [open out.nam w]

$ns namtrace-all $nf

set tf [open out.tr w]

$ns trace-all $tf

proc send_data {src dst} {

    puts “Node $src is sending data to Node $dst – ARP resolution may occur”

}

set n0 [$ns node]

set n1 [$ns node]

set n2 [$ns node]

set n3 [$ns node]

set n4 [$ns node]

$ns duplex-link $n0 $n1 1Mb 10ms DropTail

$ns duplex-link $n1 $n2 1Mb 10ms DropTail

$ns duplex-link $n2 $n3 1Mb 10ms DropTail

$ns duplex-link $n3 $n4 1Mb 10ms DropTail

set udp0 [new Agent/UDP]

$ns attach-agent $n0 $udp0

set null0 [new Agent/Null]

$ns attach-agent $n4 $null0

$ns connect $udp0 $null0

set cbr0 [new Application/Traffic/CBR]

$cbr0 set packetSize_ 500

$cbr0 set rate_ 1Mb

$cbr0 attach-agent $udp0

$ns at 0.5 “$cbr0 start”

$ns at 4.5 “$cbr0 stop”

send_data $n0 $n1

send_data $n1 $n2

send_data $n2 $n3

send_data $n3 $n4

send_data $n4 $n0

proc finish {} {

    global ns nf tf

    $ns flush-trace

    close $nf

    close $tf

    exec nam out.nam &

    exit 0

}

$ns at 5.0 “finish”

$ns run 

Screenshot: