Analysis of Quality of Service in Wimax networks

 
 
Appendix III 
The following is the PERL script used in for analysis of the trace file and to 
extract the QoS parameters. The script takes the trace file generated by ns-2 after the 
simulation is executed. It calculates throughput, packet loss, average jitter and average 
delay. 
#!/usr/bin/perl 
#This program is used to calculate the QoS Parameters from 
# NS-2 Trace file as input parameter 
# 
use List::Util qw[min max]; 
use strict; 
my $infile=$ARGV[0]; 
my $node=$ARGV[1]; 
my %packet_info; 
my %node_hash ; 
if (!open (DATA,"<$infile")) 
{ 
# Print the titles for the columns 
print "FileName Throughput PacketLoss MinJitter MaxJitter 
AvgJitter MinDelay MaxDelay AvgDelay Node TypeTraffic NumPackets 
\n"; 
exit; 
} 
#Start reading the file 
while ()
{ 
# Filter for packets 
if((/MAC.*exp/) || (/MAC.*tcp/) ||(/MAC.*cbr/) ||(/MAC.*udp/)) 
{ 
my @x = split(' '); 
my 
$action=$x[0]; 
my 
$ttime=$x[1]; 
my $node_id = $x[2]; 
my $packet_id = $x[5]; 
my $size = $x[7]; 
if(/exp/) 
{ 
$packet_info{$packet_id}->{flow} = "exp" ; 
} 

---

86
elsif (/tcp/) 
{ 
$packet_info{$packet_id}->{flow} = "tcp" ; 
} 
elsif (/cbr/) 
{ 
$packet_info{$packet_id}->{flow} = "cbr" ; 
} 
elsif (/udp/) 
{ 
$packet_info{$packet_id}->{flow} = "udp" ; 
} 
#Read the packet size 
$packet_info{$packet_id}->{size} = $size ; 
if ($action eq "s") 
{ 
if (!defined $packet_info{$packet_id}->{start}) 
{ 
$packet_info{$packet_id}->{start} = $ttime ; 
} 
$packet_info{$packet_id}->{from_node} = $node_id 
; 
$node_hash{$node_id} += 1 ; 
} 
elsif ($action eq "r") 
{ 
# The packet is received 
$packet_info{$packet_id}->{end} = $ttime ; 
$packet_info{$packet_id}->{to_node} = $node_id ; 
} 
elsif ($action eq "D") 
{ 
# The packet is dropped 
$packet_info{$packet_id}->{drop} = 1 ; 
$packet_info{$packet_id}->{from_node} 
= 
$node_id 
; 
} 
} 
} 
print_node_stats ("ALL") ; 
print "\n"; 
foreach (sort keys(%node_hash)) 
{ 
print_node_stats ($_); 
print "\n"; 
} 
sub print_node_stats () 
{ 
my $my_node = shift(@_); 
my $dropped = 0; 
my $transferred = 0; 
my 
@send_time; 
my 
@rec_time; 
my 
@packet_number; 
my 
@delay; 
my 
@from_node; 
my 
@to_node; 

---

87
my %flow = 0; 
my $count = 0; 
my $drop_count = 0; 
foreach my $packet (sort {$a <=> $b} keys(%packet_info)) 
{ 
if($my_node ne "ALL") 
{ 
if ($packet_info{$packet}->{from_node} ne 
$my_node) 
{ 
next; 
} 
} 
{ 
if ($packet_info{$packet}->{drop} == 1) 
{ 
$dropped += $packet_info{$packet}->{size}; 
$drop_count++; 
} 
Else 
{ 
if (defined($packet_info{$packet}->{start}) 
&& defined($packet_info{$packet}->{end})) 
{ 
$send_time[$count] = 
$packet_info{$packet}->{start}; 
$rec_time[$count] = 
$packet_info{$packet}->{end}; 
$from_node[$count] = 
$packet_info{$packet}->{from_node}; 
$to_node[$count] = 
$packet_info{$packet}->{to_node}; 
$transferred += $packet_info{$packet}-
>{size}; 
$packet_number[$count] = $packet; 
$delay[$count] = $rec_time[$count]- 
$send_time[$count] ; 
$flow{$from_node[$count]} = 
$packet_info{$packet}->{flow}; 
$count++; 
} 
else 
{ 
# Some packets are not marked as dropped but dont have end time so 
drop the packet 
$dropped += $packet_info{$packet}-
>{size}; 
$packet_info{$packet}->{drop} = 1; 
$drop_count++; 
} 
} 
} 
} 
my $total_size = @send_time; 
my 
@jitter; 
for my $i (0...$total_size -2) 
{ 

---

88
if ($packet_number[$i+1] == $packet_number[$i]) 
{ 
print "$i\n"; 
} 
else 
{ 
# jitter ((recvtime(j)-sendtime(j))-(recvtime(i)-
sendtime(i)))/(j-i), j > i 
$jitter[$i] = (($rec_time[$i+1] - $send_time[$i+1]) 
- ($rec_time[$i] - $send_time[$i]))/($packet_number[$i+1] - 
$packet_number[$i]); 
} 
} 
my $sum = 0; 
foreach my $jit(@jitter) 
{ 
#Get absolute value of jitter 
$jit = -1*$jit if ($jit < 0); 
$sum 
+=$jit; 
} 
my $sum_delay = 0; 
foreach 
(@delay) 
{ 
#Get absolute value of jitter 
$sum_delay 
+=$_; 
} 
my $avg_jitter = $sum/$total_size; 
my $avg_delay = $sum_delay/$total_size; 
my $per_loss = ($dropped*100)/($dropped + $transferred); 
# transferred is in Bytes. To get Kbps we multiply by 8 and 
divide by 1000 
my $throughput = ($transferred*8)/(($rec_time[$total_size - 1] 
-$send_time[0])*1000); 
$infile =~ s/\./ /g; 
$infile =~ s/tr//g; 
print "$infile "; 
print " $throughput "; 
print "$per_loss "; 
print min(@jitter); 
print " "; 
print max(@jitter); 
print " "; 
print "$avg_jitter "; 
print min(@delay); 
print " "; 
print max(@delay); 
print " "; 
print "$avg_delay "; 
print "$my_node "; 
if($my_node ne "ALL") 
{ 
print "$flow{$my_node} "; 
} 
print "$total_size "; 
} 

---