How to Start Shortest Path Routing Projects Using NS3

To start a Shortest Path Routing project in NS3  which requires replicating a network in which nodes try to find the shortest paths to destinations with the help of algorithms such as Dijkstra’s or Bellman-Ford. This project can concentrate on the custom routing protocol execution or utilise existing dynamic routing aspects of NS3.

We will instruct you on how to initiate and simulate the Shortest Path Routing Projects using NS3:

Steps to Start Shortest Path Routing Projects in NS3

  1. Understand Shortest Path Routing
  • What is Shortest Path Routing?
    • Routing strategy helps in which each node determines the shortest path to all other nodes to utilize indicators like hop count, delay, or link cost.
    • We can utilize following algorithms to execute:
      • Dijkstra’s Algorithm: Calculates the shortest path from a single source to every other node.
      • Bellman-Ford Algorithm: It helps to manage the negative edge weights however it is less effective for large networks.
  • Applications:
    • This routing is utilized in OSPF (Open Shortest Path First) and IS-IS protocols.
  1. Set Up NS3
  • Install NS3:
    • In nsnam.org, we can download and install NS3 environment.
    • We adhere to the installation instruction.
  • Verify Installation:

./waf –run scratch/test-example

  • Required Modules:
    • internet: It supports for IP-based interaction.
    • point-to-point or wifi: For making network topologies, we can utilize these module.
  1. Plan Your Shortest Path Routing Simulation
  • Objective:
    • To replicate the shortest path routing within a custom or existing protocol.
    • We measure the parameters such as path computation time, routing overhead, and packet delivery efficiency.
  • Network Topology:
    • Model a topology in which shortest path routing can be successfully experimented.
    • Example: Multi-hop network:

Node A ↔ Node B ↔ Node C ↔ Node D

↘     ↘     ↘

Node E ↔ Node F

  • Performance Metrics:
    • Path Accuracy: We need to confirm if shortest paths are selected.
    • Convergence Time: We measure duration to determine the shortest paths.
    • Packet Delivery Metrics: Calculate the performance parameters such as throughput, latency, jitter, packet loss.
  1. Implement Shortest Path Routing

Option 1: Custom Routing Protocol

Make a custom shortest path routing protocol by means of prolonging the Ipv4RoutingProtocol class.

Option 2: Leverage Existing Routing Protocols

For shortest path routing principles, we can utilize built-in protocols such as AODV (reactive) or OLSR (proactive).

4.1 Custom Shortest Path Routing

Step 1: Define a Shortest Path Protocol Class

Make a class, which manages like:

  • Topology discovery.
  • Shortest path computation using Dijkstra’s algorithm.
  • Packet forwarding.

Example Code:

#include “ns3/core-module.h”

#include “ns3/network-module.h”

#include “ns3/internet-module.h”

#include “ns3/point-to-point-module.h”

#include “ns3/applications-module.h”

using namespace ns3;

class ShortestPathRoutingApp : public Application {

public:

ShortestPathRoutingApp();

virtual ~ShortestPathRoutingApp();

void Setup(Ptr<Node> node);

private:

virtual void StartApplication();

virtual void StopApplication();

void DiscoverTopology();

void ComputeShortestPaths();

void ForwardPacket();

Ptr<Node>    m_node;

Ptr<Socket>  m_socket;

std::map<uint32_t, uint32_t> m_routingTable; // Destination -> Next Hop

};

ShortestPathRoutingApp::ShortestPathRoutingApp() : m_socket(0) {}

ShortestPathRoutingApp::~ShortestPathRoutingApp() {

m_socket = 0;

}

void ShortestPathRoutingApp::Setup(Ptr<Node> node) {

m_node = node;

}

void ShortestPathRoutingApp::StartApplication() {

m_socket = Socket::CreateSocket(m_node, UdpSocketFactory::GetTypeId());

DiscoverTopology();

ComputeShortestPaths();

}

void ShortestPathRoutingApp::StopApplication() {

if (m_socket) {

m_socket->Close();

m_socket = 0;

}

}

void ShortestPathRoutingApp::DiscoverTopology() {

// Simulate link discovery (e.g., neighbor discovery)

}

void ShortestPathRoutingApp::ComputeShortestPaths() {

// Implement Dijkstra’s algorithm to compute shortest paths

}

void ShortestPathRoutingApp::ForwardPacket() {

// Forward packets based on computed shortest paths

}

Step 2: Use the Application in a Simulation

int main(int argc, char *argv[]) {

NodeContainer nodes;

nodes.Create(4);

PointToPointHelper p2p;

p2p.SetDeviceAttribute(“DataRate”, StringValue(“10Mbps”));

p2p.SetChannelAttribute(“Delay”, StringValue(“5ms”));

NetDeviceContainer devices = p2p.Install(nodes.Get(0), nodes.Get(1));

devices.Add(p2p.Install(nodes.Get(1), nodes.Get(2)));

devices.Add(p2p.Install(nodes.Get(2), nodes.Get(3)));

InternetStackHelper stack;

stack.Install(nodes);

Ipv4AddressHelper ipv4;

ipv4.SetBase(“10.1.1.0”, “255.255.255.0”);

ipv4.Assign(devices);

Ptr<ShortestPathRoutingApp> app = CreateObject<ShortestPathRoutingApp>();

app->Setup(nodes.Get(0));

nodes.Get(0)->AddApplication(app);

app->SetStartTime(Seconds(1.0));

app->SetStopTime(Seconds(10.0));

Simulator::Run();

Simulator::Destroy();

return 0;

}

4.2 Using Existing Protocols

Use OLSR (Optimized Link State Routing Protocol)

OLSR is a proactive link-state protocol, which utilizes the shortest path principles.

#include “ns3/olsr-module.h”

OlsrHelper olsr;

InternetStackHelper stack;

stack.SetRoutingHelper(olsr);

stack.Install(nodes);

Use AODV (Ad hoc On-Demand Distance Vector)

AODV determines routes on-demand however it uses hop counts according to the metric.

#include “ns3/aodv-module.h”

AodvHelper aodv;

InternetStackHelper stack;

stack.SetRoutingHelper(aodv);

stack.Install(nodes);

  1. Test and Debug
  • Enable Logging:

export NS_LOG=ShortestPathRoutingApp=level_all:OlsrRoutingProtocol=level_all

./waf –run scratch/shortest-path-routing

  • Inspect Routing Tables: Analyse routing tables at nodes, confirming the accuracy:

Ptr<Ipv4> ipv4 = nodes.Get(0)->GetObject<Ipv4>();

ipv4->GetRoutingProtocol()->Print(std::cout);

  • Enable PCAP Tracing: To seize and examine the packets to utilize Wireshark.

p2p.EnablePcapAll(“shortest-path”);

  1. Evaluate Performance

Metrics to Measure:

  • Path Accuracy: Confirm the path correctness if the shortest paths are selected.
  • Convergence Time: Calculate the duration for nodes determining routes.
  • Packet Delivery Metrics: We need to estimate the metrics like throughput, delay, jitter, packet loss.

Use FlowMonitor:

FlowMonitorHelper flowMonitor;

Ptr<FlowMonitor> monitor = flowMonitor.InstallAll();

monitor->SerializeToXmlFile(“shortest-path-performance.xml”, true, true);

  1. Advanced Features
  • Dynamic Topologies:
    • We insert mobility models, mimicking dynamic networks.

MobilityHelper mobility;

mobility.SetMobilityModel(“ns3::ConstantPositionMobilityModel”);

mobility.Install(nodes);

  • Fault Tolerance:
    • Replicate link failures to monitor the behaviour of protocol.
  • Scalability Testing:
    • To experiment the scalability, we need to maximize the number of nodes.
  1. Document and Visualize
  • Document Implementation:
    • It offers simulation goals, protocol design, and outcomes.
  • Visualize Results:
    • Envision the packet flows to utilize NetAnim tool.
    • We want to graph the performance parameters with the help of Matplotlib or Gnuplot.

In this demonstration we clearly showed the simulation process along with sample snippets for Wireless Sensor Network that were initiated and simulated using NS3 simulation tool. Additional specific details were also provided as required.

Our team of developers is dedicated to crafting algorithms like Dijkstra’s and Bellman-Ford, ensuring you receive the clearest explanations possible. Reach out to us, and we’ll help you complete your project on schedule. If you’re looking to kick off a Shortest Path Routing Project using the NS3 tool, look no further than phdprojects.org. We promise a swift response and top-notch support to guide you through the process.