# Filename: test11.tcl

#——-Event scheduler object creation——–#
set ns [new Simulator]

#———-creating trace objects—————-#

set nt [open test11.tr w]
$ns trace-all $nt
#———-creating nam objects—————-#

set nf [open test11.nam w]
$ns namtrace-all $nf
#———-Setting color ID—————-#
$ns color 1 darkmagenta
$ns color 2 yellow
$ns color 3 blue
$ns color 4 green
$ns color 5 black

#———- Creating Network—————-#

set totalNodes 3

for {set i 0} {$i < $totalNodes} {incr i} {
set node_($i) [$ns node]
}

set server 0
set router 1
set client 2

#———- Creating Duplex Link—————-#
$ns duplex-link $node_($server) $node_($router) 2Mb 50ms DropTail
$ns duplex-link $node_($router) $node_($client) 2Mb 50ms DropTail

$ns duplex-link-op $node_($server) $node_($router) orient right
$ns duplex-link-op $node_($router) $node_($client) orient right

#————Labelling—————-#

$ns at 0.0 "$node_($server) label Server"
$ns at 0.0 "$node_($router) label Router"
$ns at 0.0 "$node_($client) label Client"

$ns at 0.0 "$node_($server) color blue"
$ns at 0.0 "$node_($client) color blue"

$node_($server) shape hexagon
$node_($client) shape hexagon
#————Data Transfer between Nodes—————-#

# Defining a transport agent for sending
set tcp [new Agent/TCP]

# Attaching transport agent to sender node
$ns attach-agent $node_($server) $tcp

# Defining a transport agent for receiving
set sink [new Agent/TCPSink]

# Attaching transport agent to receiver node
$ns attach-agent $node_($client) $sink

#Connecting sending and receiving transport agents
$ns connect $tcp $sink

#Defining Application instance
set ftp [new Application/FTP]

# Attaching transport agent to application agent
$ftp attach-agent $tcp

# Setting flow color
$tcp set fid_ 4

# data packet generation starting time
$ns at 1.0 "$ftp start"

# data packet generation ending time
$ns at 6.0 "$ftp stop"

#———finish procedure——–#

proc finish {} {
global ns nf nt
$ns flush-trace
close $nf
close $nt
puts "running nam…"
exec nam test11.nam &
exec awk -f Delay.awk test11.tr > output.tr &

exit 0
}

#Calling finish procedure
$ns at 10.0 "finish"
$ns run

############################################
#filename:Delay.awk

#——— Formula ————:

i = packet sequence number
count = Total packet count
delay[i] = receiving_time[i] – sending_time[i]
Total_Delay = Total_Delay + delay[i]
Average_Delay = Total_Delay / count
#——— AWK script Format——–#

The script has the following format:
BEGIN {}
{
content
}
END {}
Begin part comprises of initialization of variable.
Commands in the content part scan every row of trace file only once.
Ex:
if (pattern) {
action;
}

If the pattern is matched with the line in the trace in the trace file specified action will be performed.

In the END part final calculation is performed on the data obtained from the content part.

#——— Steps ————:

1. set pattern and action for sending time for each packet
2. set pattern and action for receiving time for each packet
3. apply the result in formula