# Implement three nodes point – to – point network with duplex
# links between them. Set the queue size, vary the bandwidth and find
# the number of packets dropped.
#S_HUSSAIN
#Create Simulator
set ns [new Simulator]
#Open Trace file and NAM file
set ntrace [open main.tr w]
$ns trace-all $ntrace
set namfile [open main.nam w]
$ns namtrace-all $namfile
#Finish Procedure
proc Finish {} {
global ns ntrace namfile
#Dump all the trace data and close the files
$ns flush-trace
close $ntrace
close $namfile
#Execute the nam animation file
exec nam prog1.nam &
#Show the number of packets dropped
exec echo "The number of packet drops is " &
exec grep -c "^d" prog1.tr &
exit 0
}
#Create 3 nodes
set n0 [$ns node]
set n1 [$ns node]
set n2 [$ns node]
#Label the nodes
$n0 label "TCP Source"
$n2 label "Sink"
#Set the color
$ns color 1 blue
#Create Links between nodes
#You need to modify the bandwidth to observe the variation in packet drop
$ns duplex-link $n0 $n1 1Mb 10ms DropTail
$ns duplex-link $n1 $n2 1Mb 10ms DropTail
#Make the Link Orientation
$ns duplex-link-op $n0 $n1 orient right
$ns duplex-link-op $n1 $n2 orient right
#Set Queue Size
#You can modify the queue length as well to observe the variation in packet drop
$ns queue-limit $n0 $n1 10
$ns queue-limit $n1 $n2 10
#Set up a Transport layer connection.
set tcp0 [new Agent/TCP]
$ns attach-agent $n0 $tcp0
set sink0 [new Agent/TCPSink]
$ns attach-agent $n2 $sink0
$ns connect $tcp0 $sink0
#Set up an Application layer Traffic
set cbr0 [new Application/Traffic/CBR]
$cbr0 set type_ CBR
$cbr0 set packetSize_ 100
$cbr0 set rate_ 1Mb
$cbr0 set random_ false
$cbr0 attach-agent $tcp0
$tcp0 set class_ 1
#Schedule Events
$ns at 0.0 "$cbr0 start"
$ns at 5.0 "Finish"
#Run the Simulation
$ns run Write, Run & Share TCL code online using OneCompiler's TCL online compiler for free. It's one of the robust, feature-rich online compilers for TCL language, running the latest TCL version 8.6. Getting started with the OneCompiler's TCL editor is easy and fast. The editor shows sample boilerplate code when you choose language as TCL and start coding.
OneCompiler's TCL online editor supports stdin and users can give inputs to programs using the STDIN textbox under the I/O tab. Following is a sample TCL program which takes name as input and prints hello message with your name.
set name [gets stdin]
puts "Hello $name"
Tool Command Language(TCL) is a general purpose scripting language which is commonly used for GUIs and for testing. Everything is by default string in TCL. It was created by John Osterhout in 1989.
Variable is a identifier which is used to hold the value. set is used to create variables.
set name onecompiler
When ever you want to perform a set of operations based on a condition IF-ELSE is used.
if(conditional-expression) {
#code
} else {
#code
}
You can also use if-else for nested Ifs and If-Else-If ladder when multiple conditions are to be performed on a single variable.
Switch is an alternative to If-Else-If ladder.
switch(conditional-expression) {
value1 {
# code
}
value1 {
# code
}
...
default {
# code
}
For loop is used to iterate a set of statements based on a condition.
for{start}{test}{next}{
# code
}
While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.
while(condition) {
# code
}
Array is a collection of similar data which is stored in continuous memory addresses. Array values can be fetched using index. Index starts from 0 to size-1.
set ArrayName(Index) value
Procedure is a sub-routine which contains set of statements. Uusually procedures are required when multiple calls are made to same set of statements. Procedures increases re-usuability and modularity.
proc procedureName {arguments} {
# code
}