How to Implement Least Cost Routing in NS2

To implement the Least Cost Routing in NS2 (Network Simulator 2), we can follow the given general steps. Acquire professional assistance on Least Cost Routing in NS2 from our leading developers. We possess a vast array of project concepts and are dedicated to guiding you effectively with prompt delivery. Our team excels in tailoring algorithms to align with your specific project needs:

Step-by-Step Implementations:

  1. Set up NS2 Environment

Initially, make sure that NS2 is correctly installed on the system. We can install NS2 using the below commands on Linux:

sudo apt-get install ns2

  1. Create a TCL Script for Simulation

The NS2 simulations are commonly described using the TCL (Tool Command Language) scripts. This script will define the network topology, the traffic pattern, and the routing mechanism.

Below is an instance script to get to implement the Least Cost Routing.

# Create the simulator object

set ns [new Simulator]

# Define the topology: 4 nodes (n0, n1, n2, n3)

set n0 [$ns node]

set n1 [$ns node]

set n2 [$ns node]

set n3 [$ns node]

# Define the links between nodes with cost parameters

$ns duplex-link $n0 $n1 1Mb 10ms DropTail

$ns duplex-link $n1 $n2 1Mb 10ms DropTail

$ns duplex-link $n2 $n3 1Mb 10ms DropTail

$ns duplex-link $n0 $n3 1Mb 50ms DropTail  ;# Higher cost link

# Create a traffic source, e.g., a UDP connection

set udp0 [new Agent/UDP]

$ns attach-agent $n0 $udp0

set null0 [new Agent/Null]

$ns attach-agent $n3 $null0

$ns connect $udp0 $null0

# Create a CBR traffic generator

set cbr [new Application/Traffic/CBR]

$cbr set packetSize_ 512

$cbr set interval_ 0.005

$cbr attach-agent $udp0

# Define a routing protocol: using dynamic routing or least cost

# For least-cost routing, the simulator will choose the lowest delay path (n0->n1->n2->n3)

# Start the simulation

$ns at 0.1 “$cbr start”

$ns at 5.0 “finish”

# Finish function definition

proc finish {} {

global ns

$ns halt

}

# Run the simulation

$ns run

  1. Define Routing Algorithms

NS2 simulation permits numerous kind of routing algorithms. For least cost routing, the simulator is normally selects the way with the least delay or cost among the two nodes. It can be attained using dynamic routing protocols such as DSDV (Destination-Sequenced Distance Vector) or AODV (Ad hoc On-Demand Distance Vector). However, for a particular execution of the “least-cost routing,” we may require to manually modify the link parameters such as latency, bandwidth to reflect the “cost” and consider the simulator NS2 select the least-cost path according to these values.

We can execute the routing protocol in C++ in NS2, following the below steps:

  1. Change the source code for the routing protocol.
  2. Execute the least cost algorithm by using Dijkstra’s algorithm or Bellman-Ford algorithm.
  3. Recompile NS2.
  1. Run the Simulation

When we have written the TCL script, we can run the simulation by invoking NS2:

ns your_script.tcl

It will perform the simulation rely on the topology and routing set up to provided. We can append trace files for better analysis of the outcomes.

  1. Analysis

The simulation tool NS2 outputs trace files which can be evaluated to monitor how packets traverse the network and whether the least cost routing path was selected. We can use tools such as awk, xgraph, or nam to visualize and estimate the outcomes.

This approach will instruct you on how to execute the Least Cost Routing using the tool NS2 and it includes the information about the routing algorithms and tool command language script. We will offer further specifies based on your requirements.