ns2 programs

To build a simple topology

#Create a simulator object

set ns [new Simulator]

#Open the nam trace file

set nt [open out.tr w]

$ns trace-all $nt

set nf [open out.nam w]

$ns namtrace-all $nf

#Define a 'finish' procedure

proc finish {} {

global ns nf nt

$ns flush-trace

#Close the trace file

close $nf

close $nt

#Execute nam on the trace file

exec nam out.nam &

exit 0

}

#Create two nodes

set n0 [$ns node]

set n1 [$ns node]

#Create a duplex link between the nodes

$ns duplex-link $n0 $n1 1Mb 10ms DropTail

#Call the finish procedure after 5 seconds of simulation time

$ns at 5.0 "finish"

#Run the simulation

$ns run

2. To create simple CBR traffic over UDP






set nt [open out.tr w]

$ns trace-all $nt


proc finish {} {

global ns nf

$ns flush-trace

#Close the trace file

close $nf

#Execute nam on the trace file

exec nam out.nam &

exit 0

}

#Create two nodes

set n0 [$ns node]

set n1 [$ns node]

#Create a duplex link between the nodes


set udp0 [new Agent/UDP]

$ns attach-agent $n0 $udp0

# Create a CBR traffic source and attach it to udp0

set cbr0 [new Application/Traffic/CBR]

$cbr0 set packetSize_ 500

$cbr0 set interval_ 0.005

$cbr0 attach-agent $udp0

#Create a Null agent (a traffic sink) and attach it to node n1

set null0 [new Agent/Null]

$ns attach-agent $n1 $null0

#Connect the traffic source with the traffic sink

$ns connect $udp0 $null0

#Schedule events for the CBR agent

$ns at 0.5 "$cbr0 start"

$ns at 4.5 "$cbr0 stop"


$ns at 5.0 "finish"

#Run the simulation

$ns run

3. CBR over UDP


#Open trace file

set tracefile [open out.tr w]

$ns trace-all $tracefile





proc finish {} {

global ns nf tracefile

$ns flush-trace

#Close the NAM trace file

close $nf

close $tracefile

#Execute NAM on the trace file

exec nam out.nam &

exit 0

}

set n0 [$ns node]

set n1 [$ns node]

$ns simplex-link $n0 $n1 1Mb 10ms DropTail


$ns attach-agent $n0 $udp0

set cbr [new Application/Traffic/CBR]

$cbr attach-agent $udp0


$ns attach-agent $n1 $null0


$ns at 1.0 "$cbr start"

$ns at 3.0 "finish"

$ns run

4. FTP over TCP







proc finish {} {


$ns flush-trace


close $nf

close $tracefile


exec nam out.nam &

exit 0

}

set n0 [$ns node]

set n1 [$ns node]


set tcp0 [new Agent/TCP]

$ns attach-agent $n0 $tcp0

set ftp0 [new Application/FTP]

$ftp0 attach-agent $tcp0

set tcpsink0 [new Agent/TCPSink]

$ns attach-agent $n1 $tcpsink0

$ns connect $tcp0 $tcpsink0

$ns at 1.0 "$ftp0 start"

$ns at 3.0 "finish"

$ns run

5. Topology Description1. Network consists of 4 nodes (n0, n1, n2, n3). 2. The duplex links between n0 and n2, and n1 and n2 have 2 Mbps of bandwidth and 10 ms of

delay. 3. The duplex link between n2 and n3 has 1.7 Mbps of bandwidth and 20 ms of delay. 4. Each node uses a DropTail queue, of which the maximum size is 10. 5. A “tcp” agent is attached to n0, and a connection is established to a tcp “sink” agent attached

to n3. 6. As default, the maximum size of a packet that a “tcp” agent can generate is 1KByte. 7. A tcp “sink” agent generates and sends ACK packets to the sender (tcp agent) and frees the

received packets. 8. A “udp” agent that is attached to n1 is connected to a “null” agent attached to n3. 9. A “null” agent just frees the packets received. 10. A “ftp” and a “cbr” traffic generator are attached to “tcp” and “udp” agents

respectively, 11. The “cbr” is configured to generate 1 KByte packets at the rate of 1 Mbps. 12. The “cbr” is set to start at 0.1 sec and stop at 4.5 sec, and “ftp” is set to start at

1.0 sec and stop at 4.0 sec.



#Define different colors for data flows (for NAM)

$ns color 1 Blue

$ns color 2 Red

#Open the NAM trace file






proc finish {} {


$ns flush-trace


close $nf

close $tracefile


exec nam out.nam &

exit 0

}

#Create four nodes

set n0 [$ns node]

set n1 [$ns node]

set n2 [$ns node]

set n3 [$ns node]

#Create links between the nodes



$ns duplex-link $n2 $n3 1.7Mb 20ms DropTail

#Set Queue Size of link (n2-n3) to 10

$ns queue-limit $n2 $n3 10

#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

#Monitor the queue for link (n2-n3). (for NAM)

$ns duplex-link-op $n2 $n3 queuePos 0.5

#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

#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

#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"

$ns at 1.0 "$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"


$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

# stop and wait protocol in normal situation

# features : labeling, annotation, nam-graph, and window size #monitoring


set n0 [$ns node]

set n1 [$ns node]

$ns at 0.0 "$n0 label Sender"

$ns at 0.0 "$n1 label Receiver"set nf [open A1-stop-n-wait.nam w]


set f [open A1-stop-n-wait.tr w]

$ns trace-all $f

$ns duplex-link $n0 $n1 0.2Mb 200ms DropTail

$ns duplex-link-op $n0 $n1 orient right

$ns queue-limit $n0 $n1 10Agent/TCP set nam_tracevar_ true

set tcp [new Agent/TCP]

$tcp set window_ 1

$tcp set maxcwnd_ 1

$ns attach-agent $n0 $tcp

set sink [new Agent/TCPSink]

$ns attach-agent $n1 $sink

$ns connect $tcp $sink

set ftp [new Application/FTP]

$ftp attach-agent $tcp

$ns add-agent-trace $tcp tcp

$ns monitor-agent-trace $tcp

$tcp tracevar cwnd_

$ns at 0.1 "$ftp start"

$ns at 3.0 "$ns detach-agent $n0 $tcp ; $ns detach-agent $n1 $sink"

$ns at 3.5 "finish"

$ns at 0.0 "$ns trace-annotate \"Stop and Wait with normal operation\""

$ns at 0.05 "$ns trace-annotate \"FTP starts at 0.1\""$ns at 0.11 "$ns trace-annotate \"Send Packet_0\""

$ns at 0.35 "$ns trace-annotate \"Receive Ack_0\""

$ns at 0.56 "$ns trace-annotate \"Send Packet_1\""



$ns at 1.23 "$ns trace-annotate \"Receive Ack_2 \""






$ns at 2.55 "$ns trace-annotate \"Receive Ack_5 \""


$ns at 2.99 "$ns trace-annotate \"Receive Ack_6\""$ns at 3.1 "$ns trace-annotate \"FTP stops\""

proc finish {} { global ns nf $ns flush-trace close $nf puts "running nam..." exec nam A1-stop-n-wait.nam & exit 0}$ns run

# sliding window mechanism with some features# such as labeling, annotation, nam-graph, and window size monitoringset ns [new Simulator]set n0 [$ns node]set n1 [$ns node]$ns at 0.0 "$n0 label Sender"$ns at 0.0 "$n1 label Receiver"set nf [open out.nam w]$ns namtrace-all $nf

set f [open out.tr w]$ns trace-all $f$ns duplex-link $n0 $n1 0.2Mb 200ms DropTail$ns duplex-link-op $n0 $n1 orient right$ns queue-limit $n0 $n1 10Agent/TCP set nam_tracevar_ trueset tcp [new Agent/TCP]$tcp set windowInit_ 4$tcp set maxcwnd_ 4$ns attach-agent $n0 $tcpset sink [new Agent/TCPSink]$ns attach-agent $n1 $sink$ns connect $tcp $sinkset ftp [new Application/FTP]$ftp attach-agent $tcp$ns add-agent-trace $tcp tcp$ns monitor-agent-trace $tcp$tcp tracevar cwnd_$ns at 0.1 "$ftp start"$ns at 3.0 "$ns detach-agent $n0 $tcp ; $ns detach-agent $n1 $sink"$ns at 3.5 "finish"$ns at 0.0 "$ns trace-annotate \"Sliding Window with window size 4 (normal operation)\""$ns at 0.05 "$ns trace-annotate \"FTP starts at 0.1\""$ns at 0.56 "$ns trace-annotate \"Send Packet_0,1,2,3\""$ns at 0.79 "$ns trace-annotate \"Receive Ack_0,1,2,3\""$ns at 0.99 "$ns trace-annotate \"Send Packet_4,5,6,7\""$ns at 1.23 "$ns trace-annotate \"Receive Ack_4,5,6,7\""$ns at 1.43 "$ns trace-annotate \"Send Packet_8,9,10,11\""$ns at 1.67 "$ns trace-annotate \"Receive Ack_8,9,10,11 \""$ns at 1.88 "$ns trace-annotate \"Send Packet_12,13,14,15\""$ns at 2.11 "$ns trace-annotate \"Receive Ack_12,13,14,15\""$ns at 2.32 "$ns trace-annotate \"Send Packet_16,17,18,19\""$ns at 2.56 "$ns trace-annotate \"Receive Ack_16,17,18,19\""$ns at 2.76 "$ns trace-annotate \"Send Packet_20,21,22,23\""$ns at 3.00 "$ns trace-annotate \"Receive Ack_23\""$ns at 3.1 "$ns trace-annotate \"FTP stops\""proc finish {} {global ns$ns flush-trace# puts "filtering..."puts "running nam..."exec nam out.nam &exit 0}$ns run

Simulation of Distance Vector Routing Algorithm


set nr [open thro.tr w]

$ns trace-all $nr

set nf [open thro.nam w]


proc finish { } {

global ns nr nf

$ns flush-trace

close $nf

close $nr

exec nam thro.nam &

exit 0

}

for { set i 0 } { $i < 12} { incr i 1 } {

set n($i) [$ns node]}

for {set i 0} {$i < 8} {incr i} {

$ns duplex-link $n($i) $n([expr $i+1]) 1Mb 10ms DropTail }

$ns duplex-link $n(0) $n(8) 1Mb 10ms DropTail







$ns attach-agent $n(0) $udp0






$ns attach-agent $n(5) $null0











$ns rtproto DV

$ns rtmodel-at 10.0 down $n(11) $n(5)


$ns rtmodel-at 30.0 up $n(11) $n(5)


$udp0 set fid_ 1

$udp1 set fid_ 2

$ns color 1 Red

$ns color 2 Green



$ns at 45 "finish"

$ns run

Simulation of Link State Routing Algorithm


set nr [open thro.tr w]

$ns trace-all $nr

set nf [open thro.nam w]


proc finish { } {

global ns nr nf

$ns flush-trace

close $nf

close $nr

exec nam thro.nam &

exit 0

}

for { set i 0 } { $i < 12} { incr i 1 } {

set n($i) [$ns node]}

for {set i 0} {$i < 8} {incr i} {

$ns duplex-link $n($i) $n([expr $i+1]) 1Mb 10ms DropTail }

$ns rtproto LS





$udp0 set fid_ 1

$udp1 set fid_ 2

$ns color 1 Red

$ns color 2 Green



$ns at 45 "finish"

$ns run

TRACE FILE ANALYSIS

AWK is a high level programming language which is used to process text files,named after its three orginal author's name:

A : Alfred AhoW : Peter WeinbergerK : Brian Kernighan AWK Scripts are very good in processing the data from the trace files which we get from NS2. If you want to process the trace file manually.Similar to C but more simple

Read the records line by line

$0 : the whole string in the corresponding line

$1 : the first data in the corresponding line

$2 : the second data in the corresponding line

AWK PROGRAM STRUCTUREAwk program structure contains mainly three parts;1. Begin2. Content3. End

BEGIN {<initialization>}

<pattern1> {<actionSet1>} <pattern2> {<actionSet2>} . . .

END {<final finalActionSet>}

BEGIN : Begin deals with what to be executed prior to text file processing,normally which is used to initialize variable values or constants.

CONTENT : Script which process the text file. In this part, AWK moves lines by lines (i.e., records by records) and executes the <actionSet> if the current line match with the pattern. The actions repeats until AWK reaches the end of the file.

END : This part explains what to be executed after the text file processing ie. what to print on the terminal or to show output in terminal.

An AWK example : samp.awk

BEGIN {

sum =0;

}

{

if ($1=="+")

{

sum++;

}

}

END {

printf("The number of enqueue is : %d\n",sum);

}

To run awk script, we have to use terminal window. awk -f <awk file name> <trace file name>

ex : awk -f samp.awk out.trThe ‘-f’ instructs the awk utility to get the awk program from the source file i.e from .awk file.

ns2 programs

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