Lecture 2 FINALns2

5/24/2018 Lecture 2 FINALns2

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TNK092: Network Simulation/Ntverkssimulering

Network Simulation---ns2

Lecture 2


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n3n2

n0n1

An Example with all weve seen so far.

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#Open the NAMtrace file

set nf [open out.nam w]

$ns namtrace-all $nf

#Open the Trace fileset tf [open out.tr w]

$ns trace-all $tf

#Create links between the nodes$ns duplex-link $n0 $n2 2Mb 10ms DropTail$ns duplex-link $n1 $n2 2Mb 10ms DropTail$ns duplex-link $n2 $n3 1.7Mb 20ms DropTail

#Give links 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

set ns [new Simulator]

#Define different colors

#for data flows (for NAM)

$ns color 1 Blue

$ns color 2 Red

#Define a 'finish' procedure

proc finish {} {

global ns nf tf

$ns flush-trace

#Close the NAM trace file

close $nf

#Close the Trace file

close $tf

#Execute NAM on the trace file

exec nam out.nam &

exit 0

}

#Create four nodesset n0 [$ns node]set n1 [$ns node]

set n2 [$ns node]set n3 [$ns node]

#Set Queue Size of link (n2-n3) to 10$ns queue-limit $n2 $n3 10

#Monitor the queue for link (n2-n3). (for NAM)$ns duplex-link-op $n2 $n3 queuePos 0.5

n3n2

n0

n1


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An Example with all weve seen so far..

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#Open the NAMtrace file

set nf [open out.nam w]

$ns namtrace-all $nf

#Open the Trace fileset tf [open out.tr w]

$ns trace-all $tf

#Create links between the nodes$ns duplex-link $n0 $n2 2Mb 10ms DropTail$ns duplex-link $n1 $n2 2Mb 10ms DropTail$ns duplex-link $n2 $n3 1.7Mb 20ms DropTail

#Give links 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

set ns [new Simulator]

#Define different colors

#for data flows (for NAM)

$ns color 1 Blue

$ns color 2 Red

#Define a 'finish' procedure

proc finish {} {

global ns nf tf

$ns flush-trace

#Close the NAM trace file

close $nf

#Close the Trace file

close $tf

#Execute NAM on the trace file

exec nam out.nam &

exit 0

}

#Create four nodesset n0 [$ns node]set n1 [$ns node]

set n2 [$ns node]set n3 [$ns node]

#Set Queue Size of link (n2-n3) to 10$ns queue-limit $n2 $n3 10

#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]

$ns attach-agent $n0 $tcp

set sink [new Agent/TCPSink]$ns attach-agent $n3 $sink

$ns connect $tcp $sink

$tcp set fid_ 1

#Setup an 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

n3n2

n0

n1

ftp

cbr

upd null

tcp

sink

#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 so necessary)

$ns at 4.5 "$ns detach-agent $n0 $tcp ;

in the SAME line $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

0 0.1 1.0 4.0 4.5 sec

ftp

cbr


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To create agents or traffic sources, a user should know the class names

these objects (Agent/TCP, Agnet/TCPSink, Application/FTP and so on).

Remember to look at look at the /tcl/libs/ns-default.tclfile.

This file contains the default configurable parameter value settings for

available network objects.

Hint: a good indicator of what kind of network objects are available in NS

and what are their configurable parameters.

An Example with all weve seen so far... epimyth

n3n2

n0

n1

ftp

cbr

upd null

tcp

sink

0 0.1 1.0 4.0 4.5 sec

ftp

cbr


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Tracing

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Besides the NAM trace ns2 can provide an ASCII trace file.

At every link a packet is


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Trace Enabled Simple NS Simulation Script

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About Awk

AWK is a tool that allows simple data manipulation on trace files.

Sample AWK code:

BEGIN {sum+=$2; array[N]=$2} END

{ for(i=1;i


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End to end delay (measure-delay.awk)

BEGIN {#initial the highest packet id

highest_packet_id = 0;}{

event = $1;time = $2;from = $3;to = $4;type = $5;pktsize = $6;

flow_id = $8;src = $9;dst = $10;seq_no = $11;packet_id = $12;

if ( packet_id > highest_packet_id )highest_packet_id = packet_id;

if ( start_time[packet_id] == 0 )

start_time[packet_id] = time;

if ( flow_id == 2 && action != "d" ) {if ( event == "r" ) {

end_time[packet_id] = time;}

} else {end_time[packet_id] = -1;

}

}8

awk -f measure-delay.awk out.tr > cbr-delay

END {for (packet_id=0; packet_id


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Plotting with gnuplotGnuplot(http://www.gnuplot.info/;http://www.gnuplot.info/documentation.html)

#plotdelay.plot

set term png medium #000000

set output "cbr-delay.png"

set ylabel "End-to-End delay(sec)"

set xlabel "Start transmission time(sec)"

set xrang [0:5]

set xtics 0, 0.5, 5

set yrang [0:0.1]set ytics 0, 0.01, 0.1

set title "CBR end-to-end delay"

plot "cbr-delay" title "CBR" with linespoints lt -1 pt 8

gnuplot>load plotdelay.plot

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xgraph

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xgraph cbr-delay


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Jitter (awk codes)

#cbr-jitter.awkBEGIN {

old_time=0;old_seq_no=0;i=0;}{action = $1;time = $2;node_1 = $3;node_2 = $4;

type = $5;flow_id = $8;node_1_address = $9;node_2_address = $10;seq_no = $11;packet_id = $12;

if(node_1==2 && node_2==3 && type=="cbr" &&action=="r")

{

dif=seq_no-old_seq_no;if(dif==0)dif=1;jitter[i]=(time-old_time)/dif;seq[i]=seq_no;i=i+1;old_seq_no=seq_no;old_time=time;}

}

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awk f cbr-jitter.awk out.tr > cbr-jitter

END {for (j=1; j


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Jitter (...more awk codes)#cbr-jitter2.awk

BEGIN {

highest_packet_id = 0;

}{

action = $1;time = $2;

node_1 = $3;

node_2 = $4;

type = $5;

flow_id = $8;

node_1_address = $9;


seq_no = $11;packet_id = $12;

if ( packet_id > highest_packet_id ){

highest_packet_id = packet_id;

}

if ( start_time[packet_id] == 0 ) {

pkt_seqno[packet_id] = seq_no;

start_time[packet_id] = time;}

if ( flow_id == 2 && action != "d" ){

if ( action == "r" ) {

end_time[packet_id] = time;

}

} else {

end_time[packet_id] = -1;}

}12

END {

last_seqno = 0;

last_delay = 0;

seqno_diff = 0;

for ( packet_id = 0;

packet_id cbr-jitter


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Packet loss (awk codes)# cbr-loss.awk

BEGIN {

fsDrops = 0;numFs = 0;

}

{

action = $1;

time = $2;

node_1 = $3;

node_2 = $4;

src = $5;flow_id = $8;



seq_no = $11;

packet_id = $12;

if (node_1==1 && node_2==2 && action == "+")

numFs++;

if (flow_id==2 && action == "d")fsDrops++;

}

END {

printf("number of packets sent:%d lost:%d\n", numFs,

fsDrops);

}

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Throughput (awk codes)BEGIN {init=0;i=0;

}{action = $1;time = $2;from = $3;to = $4;type = $5;pktsize = $6;flow_id = $8;src = $9;

dst = $10;seq_no = $11;packet_id = $12;

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if(action=="r" && from==2 && to==3 && flow_id==2) {pkt_byte_sum[i+1]=pkt_byte_sum[i]+ pktsize;if(init==0) {start_time = time;init = 1;}end_time[i] = time;i = i+1;}}END{ printf("%.2f\t%.2f\n", end_time[0], 0);for(j=1 ; j


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Packet loss (awk codes)BEGIN {fsDrops = 0;numFs = 0;

}{action = $1;time = $2;from = $3;to = $4;type = $5;pktsize = $6;flow_id = $8;src = $9;dst = $10;seq_no = $11;packet_id = $12;if (from==1 && to==2 && action == "+")numFs++;

if (flow_id==2 && action == "d")fsDrops++;

}

END {printf("number of packets sent:%d lost:%d\n",numFs, fsDrops);

}

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Some basic ns2 structuring

In/ns-2.34/tcl/lib:

ns-lib.tcl:

The actial simulator class, most of its member function definitions are

here

ns-default.tcl:

default values for configurable parameters for various network

components, configure the parameter in otcl which actually take effect

through C++

ns-packet.tcl:

Packet header initialization & implementation, where you register your

own packet type

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Adding your own modules...

You will develop NS2 modules in one the following file types:

What you would like to do is to incorporate these files into

NS2 how?

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File type ExampleC++ code myNewMod.ccHeader definitions myNewMod.hTcl code myNewMod.tcl


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Working assumption...

Assume that we wanted to build a multimedia application that

runs over a UDP connection.

Lets say that this application implements a "five rate media

scaling" which can respond to network congestion to some

extent by changing encoding and transmission policy pairsassociated with scale parameter values

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STEP 1:Register the new application header,by modifying the files:

/common/packet.hand /tcl/lib/ns-packet.tcl

1. In packet.hA. Look for:

// insert new packet types here

Static packet_t PT_NTYPE = 62; // This MUST be the LAST one

And insert new packet types between those 2 lines, eg:

static const packet_t PT_Multimedia = 70;

B. Look for:

class p_info {

Inpublic:

Instatic void initName() in the long list of name_ add:

name_[PT_Multimedia] = "Multimedia";

2. In ns packet.tcl- Look for:

foreach prot {

And in the list of protocols add: Multimedia19

Adding modules Step by step...


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STEP 2:Add new methods to the gentand pplicationclasses,by modifying thefiles: /common/agent.h and /apps/app.h1. In agent.h-look for:

class Agent : public Connector {

public:

Agent(packet_t pktType);

And insert new agent methods as e.g.:

virtual int supportMM() {return 0;}

virtual void enableMM() {}

2. In app.h-look for:

class Application : public Process {

public:

Application();

And in that list also insert your application methods defintions as e.g.:

virtual void recv_msg(int nbytes, const char *msg = 0){}

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STEP 3:Set defaults for the new configurable parameters,

in /tcl/lib/ns-default.tcl add

......

Application/MmApp set rate0_ 0.3mb



Application/MmApp set rate3_ 1.2mbApplication/MmApp set rate4_ 1.5mb

Application/MmApp set pktsize_ 1000

Application/MmApp set random_ false

......

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STEP 4:Modify the MakefileAssuming that you have all three .h, .ccand .tclfile types you must make the followingmodifications (if not, reduce steps accordingly).

Note: the Makefile lies in the /ns-2.23 directory

Lets assume your files are in /ns-2.34/myWork

You will have to modify three places in theMakefile

1.OBJ_CC

2.NS_TCL_LIB

3.INCLUDE

As follows:

1. Look for

OBJ_CC = \

And add:

myDir/myNewMod.o \

To one line below 22


File type ExampleC++ code

myNewMod.cc

Header definitions myNewMod.hTcl code myNewMod.tcl


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2. Look for

NS_TCL_LIB = \

And add:

myDir/myfile.tcl \To one line below

3. (OPTIONAL) Look for

INCLUDES = \

And add:-I. /myWorks \To one line below

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Adding modules Step by step...File type ExampleC++ code myNewMod.ccHeader definitions myNewMod.hTcl code myNewMod.tcl


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STEP 6:

Recompile the software

./make

Note:These will be key instruction steps for Lab Assignment 2

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Lecture 2 FINALns2