How to implement TCP protocols in ns2

 

To implement TCP protocols in Network Simulator 2 (NS2) has numerous steps that include setup the network simulation to use numerous TCP variants, like TCP Tahoe, TCP Reno, TCP NewReno, and TCP Vegas. The NS3 can handle the several TCP variants and we can mimic the characteristics in diverse network scenarios. The given below are the procedure to implement and simulate TCP protocols in NS2.

Step-by-Step Guide to Implement TCP Protocols in NS2

Step 1: Install NS2

Make sure that NS2 is installed on system.

Step 2: Choose a TCP Variant

NS2 supports several TCP variants, including:

  • TCP Tahoe
  • TCP Reno
  • TCP NewReno
  • TCP Vegas

We can choose the TCP variant that want to simulate.

Step 3: Create a Simulation Script

Generate a Tcl script to configure the network and emulate the TCP traffic using the chosen TCP variant.

  1. Create a new Tcl script: Open a text editor and generate a new file, for instance, tcp_example.tcl.
  2. Set up the simulation environment: Describe the simulator, configure the network topology, and setup the parameters specific to the simulation.

# Create a simulator object

set ns [new Simulator]

# Define options for the simulation

set val(chan)   Channel/WirelessChannel    ;# Channel type

set val(prop)   Propagation/TwoRayGround   ;# Propagation model

set val(netif)  Phy/WirelessPhy            ;# Network interface type

set val(mac)    Mac/802_11                 ;# MAC type

set val(ifq)    Queue/DropTail/PriQueue    ;# Interface Queue type

set val(ll)     LL                         ;# Link layer type

set val(ant)    Antenna/OmniAntenna        ;# Antenna type

set val(ifqlen) 50                         ;# Max packet in ifq

set val(nn)     2                          ;# Number of nodes

set val(stop)   10.0                       ;# Simulation time

set val(x)      500                        ;# X dimension of topography

set val(y)      500                        ;# Y dimension of topography

# Initialize the topology object

set topo [new Topography]

$topo load_flatgrid $val(x) $val(y)

# Create the God object

create-god $val(nn)

# Configure the nodes

$ns node-config -llType $val(ll) \

-macType $val(mac) \

-ifqType $val(ifq) \

-ifqLen $val(ifqlen) \

-antType $val(ant) \

-propType $val(prop) \

-phyType $val(netif) \

-channelType $val(chan) \

-topoInstance $topo \

-agentTrace ON \

-routerTrace ON \

-macTrace ON \

-movementTrace ON

# Create nodes

for {set i 0} {$i < $val(nn)} {incr i} {

set node_($i) [$ns node]

$node_($i) random-motion 0

}

# Define node movement (Optional for mobile nodes)

$node_(0) set X_ 50.0

$node_(0) set Y_ 50.0

$node_(0) set Z_ 0.0

$node_(1) set X_ 450.0

$node_(1) set Y_ 450.0

$node_(1) set Z_ 0.0

  1. Setup TCP Agents: Configure TCP agents and attach them to the nodes.

# Setup a TCP agent and attach it to node 0

set tcp [new Agent/TCP]

$ns attach-agent $node_(0) $tcp

# Set the TCP variant (Reno, NewReno, Tahoe, Vegas, etc.)

$tcp set class_ TCP/Reno

# Setup a TCP Sink agent and attach it to node 1

set sink [new Agent/TCPSink]

$ns attach-agent $node_(1) $sink

# Connect the TCP agent with the TCP Sink

$ns connect $tcp $sink

  1. Setup an Application to Generate Traffic:

# Setup a FTP application over the TCP agent

set ftp [new Application/FTP]

$ftp attach-agent $tcp

$ftp set type_ FTP

$ftp start

  1. Setup Simulation End:

# Define simulation end time

$ns at $val(stop) “stop”

$ns at $val(stop) “$ns nam-end-wireless $val(stop)”

$ns at $val(stop) “exit 0”

proc stop {} {

global ns tracefile namfile

$ns flush-trace

close $tracefile

close $namfile

}

# Run the simulation

$ns run

Example: Implementing TCP Variants in NS2

Implementing TCP Reno:

$tcp set class_ TCP/Reno

Implementing TCP NewReno:

$tcp set class_ TCP/Newreno

Implementing TCP Tahoe:

$tcp set class_ TCP/Tahoe

Implementing TCP Vegas:

$tcp set class_ TCP/Vegas

Step 4: Run the Simulation

  1. Save the Tcl script (tcp_example.tcl).
  2. Open a terminal and navigate to the directory in which we can save the Tcl script.
  3. Execute the simulation using the following command:

ns tcp_example.tcl

This command will generate trace files and optionally a network animation file (if enabled in script).

Step 5: Analyse the Results

Use trace files and network animator (NAM) to evaluate the performance of the TCP protocol that concentrates on the performance metrics such as throughput, congestion window size, packet loss, and latency.

Step 6: Visualize the Results (Optional)

If we have allowed the network animator (NAM) in the script, we can visualize the simulation:

nam tcp_example.nam

This will open the NAM window, in which we can see the network topology and the behaviour of the TCP protocol during the simulation.

Additional Considerations

  • Congestion Control: Evaluate on how diverse TCP variants manage the congestion control.
  • Packet Loss: Monitor on how each TCP variant reacts to packet loss in the network.
  • Performance Metrics: Evaluate and relate the performance of diverse TCP variants in terms of throughput, latency, and fairness.

This module demonstrates how to setup and implement the TCP protocols using the ns2 simulator. Further details will be provided about how the TCP protocols will be performing in other simulation tool. For TCP Protocol implementation in NS2, visit ns2project.com our developers will give you tailored guidance. We also handle TCP variants such as TCP Tahoe, TCP Reno, TCP NewReno, and TCP Vegas simulation for your projects. Let us help you with your project.