CN 1 - POINT TO POINT NETWORK WITH DUPLEX LINKS

1. Implement three nodes point – to – point network with duplex links between them. Set the queue size, vary the bandwidth and find the number of packets dropped.

cn1.tcl - PROGRAM

# Simulation parameters setup

set val(stop) 6.0 ; # stopping time of the simulation

# Initialization

#Create a ns simulator

set ns [new Simulator]

#Open the NS trace file

set tracefile [open 1.tr w]

$ns trace-all $tracefile

#Open the NAM trace file

set namfile [open 1.nam w]

$ns namtrace-all $namfile

# Nodes Definition

#Create 3 nodes

set n1 [$ns node]

set n2 [$ns node]

set n3 [$ns node]

# Links Definition

#Createlinks between nodes

$ns duplex-link $n1 $n2 1000Kb 60ms DropTail

$ns queue-limit $n1 $n2 14

$ns duplex-link $n2 $n3 500Kb 60ms DropTail

$ns queue-limit $n2 $n3 4

$ns duplex-link-op $n1 $n2 queuePos 0.5

$ns duplex-link-op $n2 $n3 queuePos 0.2

# Agents Definition

#Setup a TCP connection

set tcp0 [new Agent/TCP]

$ns attach-agent $n1 $tcp0

set sink1 [new Agent/TCPSink]

$ns attach-agent $n3 $sink1

$ns connect $tcp0 $sink1

$tcp0 set packetSize_ 1500

# Applications Definition

#Setup a FTP Application over TCP connection

set ftp0 [new Application/FTP]

$ftp0 attach-agent $tcp0

$ns at 0.2 "$ftp0 start"

$ns at 5.0 "$ftp0 stop"

# Termination

#Define a 'finish' procedure

proc finish {} {

global ns tracefile namfile

$ns flush-trace

close $tracefile

close $namfile

exec nam 1.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

cn1.awk - PROGRAM

BEGIN {

count=0;

total=0;

} 

{ 

event=$1;

if(event=="d") {

count++;

}

}

END {

printf("No of packets dropped : %d\n",count);

}

STEPS :

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OUTPUT :

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