m. dahshan - tcom52721 tcom 5272 telecomm lab dr. mostafa dahshan ou-tulsa 4w 2 nd floor 660-3713...

M. Dahshan - TCOM5272 1

TCOM 5272Telecomm Lab

Dr. Mostafa DahshanOU-Tulsa 4W 2nd [email protected]


References

Awk – A Tutorial and Introductionwww.grymoire.com/Unix/Awk.html

NS by Examplenile.wpi.edu/NS/


Awk utility

Awk is an excellent filtering and reporting utility

A pseudo-C interpreter Same C arithmetic Supports associative arrays (array

index can be a variable of any type)


Awk – Basic Structure

pattern { action } pattern specifies when action is

performed Awk is line oriented Default pattern matches every line Two other important patterns

BEGIN END


Awk – Basic Structure Example on an NS trace file

+ 0.5075 0 1 cbr 210 ------- 0 0.0 1.0 2 2- 0.5075 0 1 cbr 210 ------- 0 0.0 1.0 2 2r 0.51112 0 1 cbr 210 ------- 0 0.0 1.0 0 0 BEGIN {print “Time\tSequence Number”}

{print $2”\t”$11}END {print “DONE”}

Output Time Sequence Number

0.5075 20.5075 20.51112 0DONE


Calculating Packet DelayBEGIN { # simple awk script to generate end-to-end

# packet lifetime statistics # in a form suitable for plotting with xgraph # Lloyd Wood, July 1999. #

http://www.ee.surrey.ac.uk/Personal/L.Wood/ns/

highest_packet_id = 0;}


Calculating Packet Delay{ action = $1; time = $2; node_1 = $3; node_2 = $4; src = $5; flow_id = $8; node_1_address = $9; node_2_address = $10; seq_no = $11; packet_id = $12;


Calculating Packet Delay if ( packet_id > highest_packet_id ) highest_packet_id = packet_id;

# getting start time is not a problem, provided you're not starting # traffic at 0.0. # could test for sending node_1_address or flow_id here. if ( start_time[packet_id] == 0 ) start_time[packet_id] = time; # only useful for small unicast where packet_id doesn't wrap. # checking receive means avoiding recording drops if ( action != "d" ) { if ( action == "r" ) {

# could test for receiving node_2_address or flow_id here. end_time[packet_id] = time; } } else { end_time[packet_id] = -1; }}


Calculating Packet DelayEND { for ( packet_id = 0; packet_id <=

highest_packet_id; packet_id++ ){

start = start_time[packet_id]; end = end_time[packet_id]; packet_duration = end - start;

if ( start < end ) printf("%d %f\n", packet_id , packet_duration);

}}


Calculate Average Delay

First, calculate packet delay {

#increment number of lines num_lines++; #sum the delay values #column 2 is the packet delay sum_delay=sum_delay+$2;} END {print sum_delay/num_lines}


Calculating Dropped Packets

BEGIN{dropped=0}

{

action = $1;

if(action=="d")

dropped++;

}

END{print dropped}


Calculating Throughput Throughput = total number of bytes

received BEGIN{dest=3}

{ action = $1; node2 = $4; packet_size = $6; if(action=="r" && node2=dest) throughput + = packet_size;}END{throughput}


Calculating Jitter

Jitter = difference between packet delays

First, calculate packet delay


Calculating Jitter

BEGIN {old_delay=0.0;}

{

delay = $2;

if(old_delay>0) jitter=delay-old_delay;

else jitter=0.0;

#if(jitter<0) jitter = -jitter;

old_delay = delay;

print $1 " " jitter;

}


cat, grep, wc

We can simplify processing by doing some pre-filtering using grep

We can also do some quick calculations by combining multiple small commands

Take the output of a command as an input to the next command (pipes)


Print only CBR Traffic grep cbr out.tr+ 0.1 1 2 cbr 1000 ------- 2 1.0 3.1 0 0- 0.1 1 2 cbr 1000 ------- 2 1.0 3.1 0 0+ 0.108 1 2 cbr 1000 ------- 2 1.0 3.1 1 1- 0.108 1 2 cbr 1000 ------- 2 1.0 3.1 1 1r 0.114 1 2 cbr 1000 ------- 2 1.0 3.1 0 0+ 0.114 2 3 cbr 1000 ------- 2 1.0 3.1 0 0- 0.114 2 3 cbr 1000 ------- 2 1.0 3.1 0 0+ 0.116 1 2 cbr 1000 ------- 2 1.0 3.1 2 2- 0.116 1 2 cbr 1000 ------- 2 1.0 3.1 2 2r 0.122 1 2 cbr 1000 ------- 2 1.0 3.1 1 1


Print CBR Traffic From 2 to 3 grep "2 3 cbr" out.tr + 0.114 2 3 cbr 1000 ------- 2 1.0 3.1 0 0- 0.114 2 3 cbr 1000 ------- 2 1.0 3.1 0 0+ 0.122 2 3 cbr 1000 ------- 2 1.0 3.1 1 1- 0.122 2 3 cbr 1000 ------- 2 1.0 3.1 1 1+ 0.13 2 3 cbr 1000 ------- 2 1.0 3.1 2 2- 0.13 2 3 cbr 1000 ------- 2 1.0 3.1 2 2+ 0.138 2 3 cbr 1000 ------- 2 1.0 3.1 3 3- 0.138 2 3 cbr 1000 ------- 2 1.0 3.1 3 3r 0.138706 2 3 cbr 1000 ------- 2 1.0 3.1 0 0+ 0.146 2 3 cbr 1000 ------- 2 1.0 3.1 4 4


Print Only Received Packets grep ^r out.tr r 0.114 1 2 cbr 1000 ------- 2 1.0 3.1 0 0r 0.122 1 2 cbr 1000 ------- 2 1.0 3.1 1 1r 0.13 1 2 cbr 1000 ------- 2 1.0 3.1 2 2r 0.138 1 2 cbr 1000 ------- 2 1.0 3.1 3 3r 0.138706 2 3 cbr 1000 ------- 2 1.0 3.1 0 0r 0.146 1 2 cbr 1000 ------- 2 1.0 3.1 4 4r 0.146706 2 3 cbr 1000 ------- 2 1.0 3.1 1 1r 0.154 1 2 cbr 1000 ------- 2 1.0 3.1 5 5r 0.154706 2 3 cbr 1000 ------- 2 1.0 3.1 2 2r 0.162 1 2 cbr 1000 ------- 2 1.0 3.1 6 6


Print CBR Received at Node 3 grep ^r out.tr | grep "2 3 cbr" r 0.138706 2 3 cbr 1000 ------- 2 1.0 3.1 0 0r 0.146706 2 3 cbr 1000 ------- 2 1.0 3.1 1 1r 0.154706 2 3 cbr 1000 ------- 2 1.0 3.1 2 2r 0.162706 2 3 cbr 1000 ------- 2 1.0 3.1 3 3r 0.170706 2 3 cbr 1000 ------- 2 1.0 3.1 4 4r 0.178706 2 3 cbr 1000 ------- 2 1.0 3.1 5 5r 0.186706 2 3 cbr 1000 ------- 2 1.0 3.1 6 6r 0.194706 2 3 cbr 1000 ------- 2 1.0 3.1 7 7r 0.202706 2 3 cbr 1000 ------- 2 1.0 3.1 8 8r 0.210706 2 3 cbr 1000 ------- 2 1.0 3.1 9 9


Calculate Dropped Packets!

grep ^d out.tr | wc –l 18


Trace Analysis Example

Download the file Trace Analysis Examplehttp://nile.wpi.edu/NS/Example/ns-simple-trace.tcl


Activity 1: Calculate Packet Delay Use the provided packet delay script

to calculate the delay for CBR traffic only!

Save the output to a file cbr_delay.txt Commands:

ns ns-simple-trace.tcl grep cbr out.tr | awk -f

pkt_delay.awk > cbr_delay.txt


Activity 2: Calculate Jitter

Use the provided packet jitter script to calculate the delay for CBR traffic

Save the output to a file cbr_jitter.txt Commands:

awk -f jitter.awk cbr_delay.txt > cbr_jitter.txt


Activity 3: Plot Delay and Jitter

Use xgraph or gnuplot to plot the delay and jitter for CBR traffic on the same graph

For xgraph xgraph cbr_delay.txt

cbr_jitter.txt


Activity 3: Plot Delay and Jitter

Using gnuplot gnuplot

gnuplot>set key left top Right noreverse enhanced box

gnuplot>set xlabel "Packet ID"

gnuplot>set ylabel "Delay and Jitter (sec)"

gnuplot>plot “cbr_delay.txt" using 1:2 title “Packet Delay" with lines 1, “cbr_jitter.txt" using 1:2 title “Jitter" with lines 2


Activity 4: Stochastic Fair Queue

Edit the ns-sample-trace.tcl script Change the queue type from DropTail

to SFQ Save as ns-sample-trace-sfq.tcl Recalculate delay, jitter and plot the

results (cbr_delay_sfq.txt, cbr_jitter_sfq.txt)

Discuss your findings


Activity 4: Random Early Detection

Edit the ns-sample-trace.tcl script Change the queue type from DropTail

to RED Save as: ns-sample-trace-red.tcl Recalculate delay, jitter and plot the

results (cbr_delay_red.txt, cbr_jitter_red.txt)

Discuss your findings

m. dahshan - tcom52721 tcom 5272 telecomm lab dr. mostafa dahshan ou-tulsa 4w 2 nd floor 660-3713...

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