CN 2 – TRANSMISSION OF PING MESSAGES

  CN LAB
2. Implement transmission of ping messages/trace route over a network topology consisting of 6 nodes and find the number of packets dropped due to congestion.

cn2.tcl – PROGRAM

set val(stop) 10.0 ; # time of simulation end

#Create a ns simulator
set ns [new Simulator]

#Open the NS trace file
set tracefile [open 3.tr w]
$ns trace-all $tracefile

#Open the NAM trace file
set namfile [open 3.nam w]
$ns namtrace-all $namfile

#Create 7 nodes
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]

#Create links between nodes
$ns duplex-link $n0 $n1 1Mb 50ms DropTail
$ns queue-limit $n0 $n1 50
$ns duplex-link $n0 $n3 1Mb 50ms DropTail
$ns queue-limit $n0 $n3 50
$ns duplex-link $n0 $n4 1Mb 50ms DropTail
$ns queue-limit $n0 $n4 50
$ns duplex-link $n0 $n5 1Mb 50ms DropTail
$ns queue-limit $n0 $n5 2
$ns duplex-link $n0 $n2 1Mb 50ms DropTail
$ns queue-limit $n0 $n2 2
$ns duplex-link $n0 $n6 1Mb 50ms DropTail
$ns queue-limit $n0 $n6 1

#Give node position (for NAM)
$ns duplex-link-op $n0 $n1 orient right-up
$ns duplex-link-op $n0 $n2 orient right
$ns duplex-link-op $n0 $n3 orient right-down
$ns duplex-link-op $n0 $n4 orient left-down
$ns duplex-link-op $n0 $n5 orient left
$ns duplex-link-op $n0 $n6 orient left-up

Agent/Ping instproc recv {from rtt} {
$self instvar node_
puts “node [$node_ id] received ping answer from $from with round-trip-time $rtt ms.”
}

set p1 [new Agent/Ping]
set p2 [new Agent/Ping]
set p3 [new Agent/Ping]
set p4 [new Agent/Ping]
set p5 [new Agent/Ping]
set p6 [new Agent/Ping]

$ns attach-agent $n1 $p1
$ns attach-agent $n2 $p2
$ns attach-agent $n3 $p3
$ns attach-agent $n4 $p4
$ns attach-agent $n5 $p5
$ns attach-agent $n6 $p6

$ns connect $p1 $p4
$ns connect $p2 $p5
$ns connect $p3 $p6

$ns at 0.2 “$p1 send”
$ns at 0.4 “$p2 send”
$ns at 0.6 “$p3 send”
$ns at 1.0 “$p4 send”
$ns at 1.2 “$p5 send”
$ns at 1.4 “$p6 send”

proc finish {} {
global ns tracefile namfile
$ns flush-trace
close $tracefile
close $namfile
exec nam 3.nam &
exit 0
}

$ns at $val(stop) “$ns nam-end-wireless $val(stop)”
$ns at $val(stop) “finish”
$ns at $val(stop) “puts “done” ; $ns halt”
$ns run

cn2.awk – PROGRAM

BEGIN {
count=0;
}
{
event=$1;
if(event==”d”) {
count++;
}
}
END {
printf(“No of packets dropped : %dn”,count);

}

STEPS :
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OUTPUT :
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