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The document outlines a simulation setup for a three-node point-to-point network with duplex links, focusing on varying bandwidth and queue sizes to analyze packet drop rates. It includes code for creating nodes, establishing links, and setting up TCP connections and traffic generation. The simulation is designed to record trace data and visualize results using NAM (Network Animator).

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kavichengappa
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12 views2 pages

1

The document outlines a simulation setup for a three-node point-to-point network with duplex links, focusing on varying bandwidth and queue sizes to analyze packet drop rates. It includes code for creating nodes, establishing links, and setting up TCP connections and traffic generation. The simulation is designed to record trace data and visualize results using NAM (Network Animator).

Uploaded by

kavichengappa
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as PDF, TXT or read online on Scribd
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1.

Implement Three nodes point – to – point network with duplex links


between them for different topologies. 1Set the queue size, vary the
bandwidth, and find the number of packets dropped for various iterations.

#Create Simulator
set ns [new Simulator]
#Open Trace file and NAM file
set ntrace [open prog1.tr w]
$ns trace-all $ntrace
set namfile [open prog1.nam w]
$ns namtrace-all $namfile
#Finish Procedure
proc Finish {} {
global ns ntrace namfile
#Dump all the trace data and close the files
$ns flush-trace
close $ntrace
close $namfile
#Execute the nam animation file
exec nam prog1.nam &
#Show the number of packets dropped
exec echo "The number of packet drops is " &
exec grep -c "^d" prog1.tr &
exit 0
}
#Create 3 nodes
set n0 [$ns node]
set n1 [$ns node]
set n2 [$ns node]
#Label the nodes
$n0 label "TCP Source"
$n2 label "Sink"
#Set the color
$ns color 1 blue
#Create Links between nodes
#You need to modify the bandwidth to observe the variation in packet drop
$ns duplex-link $n0 $n1 1Mb 10ms DropTail
$ns duplex-link $n1 $n2 1Mb 10ms DropTail
#Make the Link Orientation
$ns duplex-link-op $n0 $n1 orient right
$ns duplex-link-op $n1 $n2 orient right
#Set Queue Size
#You can modify the queue length as well to observe the variation in packet drop
$ns queue-limit $n0 $n1 10
$ns queue-limit $n1 $n2 10
#Set up a Transport layer connection
set tcp0 [new Agent/TCP]
$ns attach-agent $n0 $tcp0
set sink0 [new Agent/TCPSink]
$ns attach-agent $n2 $sink0
$ns connect $tcp0 $sink0
#Set up an Application layer Tra[ic
set cbr0 [new Application/Tra[ic/CBR]
$cbr0 set type_ CBR
$cbr0 set packetSize_ 100
$cbr0 set rate_ 1Mb
$cbr0 set random_ false
$cbr0 attach-agent $tcp0
$tcp0 set class_ 1
#Schedule Events
$ns at 0.0 "$cbr0 start"
$ns at 5.0 "Finish"
#Run the Simulation
$ns run

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