Computer Networks (CN)

NS2 Simple Program

#	* Simple NS2 Program
#	* Author:PracsPedia		www.pracspedia.com

#Create a simulator object
set ns [new Simulator]

#Define different colors for data flows (for NAM)
$ns color 1 Green
$ns color 2 Blue

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

#Define a 'finish' procedure
proc finish {} {
        global ns nf
        $ns flush-trace
        #Close the NAM trace file
        close $nf
        #Execute NAM on the trace file
        exec nam out.nam &
        exit 0
}

#Create 8 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 [$ns node]
set n7 [$ns node]

#Create links between the nodes
$ns duplex-link $n0 $n2 0.5Mb 	10ms DropTail
$ns duplex-link $n1 $n2 2Mb 	10ms DropTail
$ns duplex-link $n2 $n3 1.7Mb 	20ms DropTail
$ns duplex-link $n3 $n4 2Mb 	10ms DropTail
#$ns duplex-link $n3 $n6 1.5Mb 	30ms DropTail
$ns duplex-link $n4 $n5 1Mb 	10ms DropTail
$ns duplex-link $n4 $n6 1.7Mb 	20ms DropTail
$ns duplex-link $n5 $n7 2.2Mb 	10ms DropTail
$ns duplex-link $n6 $n7 2.7Mb 	5ms DropTail

#Set Queue Size of link (n2-n3) to 20
$ns queue-limit $n2 $n3 10
$ns queue-limit $n4 $n5 10
$ns queue-limit $n6 $n7 20

#Give node position (for NAM)
$ns duplex-link-op $n0 $n2 orient right-down
$ns duplex-link-op $n1 $n2 orient right-up
$ns duplex-link-op $n2 $n3 orient right-down
$ns duplex-link-op $n3 $n4 orient right-up
$ns duplex-link-op $n4 $n5 orient right-up
$ns duplex-link-op $n4 $n6 orient right-down
$ns duplex-link-op $n5 $n7 orient right-down
$ns duplex-link-op $n6 $n7 orient right-up

#Monitor the queue for link (n2-n3). (for NAM)
$ns duplex-link-op $n2 $n3 queuePos 0.5
$ns duplex-link-op $n4 $n5 queuePos 0.4
$ns duplex-link-op $n6 $n7 queuePos 0.2


#Setup a TCP connection
set tcp [new Agent/TCP]
$tcp set class_ 2
$ns attach-agent $n0 $tcp
set sink [new Agent/TCPSink]
$ns attach-agent $n5 $sink
$ns connect $tcp $sink
$tcp set fid_ 1

#Setup a FTP over TCP connection
set ftp [new Application/FTP]
$ftp attach-agent $tcp
$ftp set type_ FTP


#Setup a UDP connection
set udp [new Agent/UDP]
$ns attach-agent $n1 $udp
set null [new Agent/Null]
$ns attach-agent $n6 $null
$ns connect $udp $null
$udp set fid_ 2

#Setup a CBR over UDP connection
set cbr [new Application/Traffic/CBR]
$cbr attach-agent $udp
$cbr set type_ CBR
$cbr set packet_size_ 1000
$cbr set rate_ 1mb
$cbr set random_ false


#Schedule events for the CBR and FTP agents
$ns at 0.1 "$cbr start"
$ns at 0.5 "$ftp start"
$ns at 4.0 "$ftp stop"
$ns at 4.5 "$cbr stop"

#Detach tcp and sink agents (not really necessary)
$ns at 4.5 "$ns detach-agent $n0 $tcp ; $ns detach-agent $n5 $sink"

#Call the finish procedure after 5 seconds of simulation time
$ns at 5.0 "finish"

#Print CBR packet size and interval
puts "CBR packet size = [$cbr set packet_size_]"
puts "CBR interval = [$cbr set interval_]"

#Run the simulation
$ns run

								
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