Wired and Wireless Examples in ns2
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This document describes a wired network simulation with 4 nodes connected by links of varying bandwidth and delay. A TCP connection and FTP application are established between nodes n0 and n3, while a CBR traffic source runs over UDP between nodes n1 and n3. The simulation is run for 5 seconds, with the CBR starting at 0.1s and the FTP starting at 1s and stopping at 4s, and the CBR stopping at 4.5s. NAM is used to visualize the network traffic and queue sizes.
![Wired Example….
#Create a simulator object
set ns [new Simulator]
#Open the NAM trace file
set nf [open out.nam w]
$ns namtrace-all $nf
#color for data flow
$ns color 1 red
$ns color 2 blue
#Create four nodes
set n0 [$ns node]
set n1 [$ns node]
set n2 [$ns node]
set n3 [$ns node]
4](https://image.slidesharecdn.com/session3-wiredandwirelessexamples-171209043926/85/Wired-and-Wireless-Examples-in-ns2-4-320.jpg)
![Wired Example….
#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 $n3 $sink
$ns connect $tcp $sink
$tcp set fid_ 1
7](https://image.slidesharecdn.com/session3-wiredandwirelessexamples-171209043926/85/Wired-and-Wireless-Examples-in-ns2-7-320.jpg)
![Wired Example….
#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 $n3 $null
$ns connect $udp $null
$udp set fid_ 2 8](https://image.slidesharecdn.com/session3-wiredandwirelessexamples-171209043926/85/Wired-and-Wireless-Examples-in-ns2-8-320.jpg)
![Wired Example….
#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
9](https://image.slidesharecdn.com/session3-wiredandwirelessexamples-171209043926/85/Wired-and-Wireless-Examples-in-ns2-9-320.jpg)
![Wired Example….
#Schedule events for the CBR and FTP agents
$ns at 0.1 "$cbr start"
$ns at 1.0 "$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 $n3 $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
10](https://image.slidesharecdn.com/session3-wiredandwirelessexamples-171209043926/85/Wired-and-Wireless-Examples-in-ns2-10-320.jpg)
Wired and Wireless Examples in ns2
- 3. Wired Example…. • This network consists of 4 nodes (n0, n1, n2, n3) as shown in above figure. • The duplex links between n0 and n2, and n1 and n2 have 2 Mbps of bandwidth and 10ms of delay. • The duplex link between n2 and n3 has 1.7 Mbps of bandwidth and 20 ms of delay. • Each node uses a DropTail queue, of which the maximum size is 10. 3
- 11. Output 11