How to Start Irregular Topology Projects using OMNeT++

To stimulate an Irregular Topology project in OMNeT++ has been including generate a network where the nodes are linked in a non-standard or non-regular manner. Irregular topologies can be demonstrating the networks by nodes that do not adhere to simple structures such as grids, rings, or stars. Instead, these topologies can involves the random connections or asymmetric layouts, like as random networks, real-world network graphs, or custom-designed networks in which node positions are connections not uniformly distributed.

We apply an Irregular Topology in OMNeT++, you would typically use NED files the network architecture explanation, and you could write C++ code for modifying the behavior of nodes and links. Here’s a step-by-step guide for starting an irregular topology project:

Steps to Start Irregular Topology Projects using OMNeT++

  1. Install OMNeT++

If OMNeT++ is not installed yet, download it from the official OMNeT++ website: https://omnetpp.org/download/, and follow the installation instructions for your platform.

  1. Create a New OMNeT++ Project
  1. Open OMNeT++ IDE.
  2. Start File > New > OMNeT++ Project.
  3. Select the Simple Network as the project template.
  4. Name the project (e.g., IrregularTopology).
  5. Click Finish to build the new project.
  1. Define the Irregular Topology in NED Files

We build an irregular topology; we will have a state of modification node placements and connections among nodes. We cannot observe a simple grid or predefined organization. In its place, we can either manually describe the irregular connections or build them programmatically.

Example 1: Manual Irregular Topology Definition

Designed for this, we can manually describe the irregular connections among nodes in a NED file. Here’s a simple sample of an irregular topology with arbitrary connections between nodes.

network IrregularTopology

{

submodules:

node1: SimpleNode;

node2: SimpleNode;

node3: SimpleNode;

node4: SimpleNode;

node5: SimpleNode;

connections:

node1.out –> node2.in;

node2.out –> node3.in;

node3.out –> node5.in;

node4.out –> node1.in;

node4.out –> node5.in;

}

In this example:

  • We have 5 nodes such as node1 to node5.
  • The nodes are connected by random links which do not track the regular design. For instance, node1 is connected to node2, while node4 is connected to node1 and node5, build an irregular design of connections.

Example 2: Randomly Generated Irregular Topology

Intended for a further complex and dynamic irregular topology, you can create random connections among nodes. This can be complete using C++ code classified the initialize () technique to programmatically introduce the connections.

  1. Implement Node Behavior in C++

Then, we will express the behavior of nodes using C++ code. Every node can behave several reliant on the kind of irregular topology we are replicating. For sample, we may need to every node to communicate by arbitrarily choose the neighbours, or replicate the modify routing logic.

Example: SimpleNode.cc (Node Behavior)

#include <omnetpp.h>

class SimpleNode : public cSimpleModule

{

private:

cMessage *msg;  // Message object for transmission

protected:

virtual void initialize() override;

virtual void handleMessage(cMessage *msg) override;

void transmitData();

void receiveData(cMessage *msg);

public:

~SimpleNode();

};

Define_Module(SimpleNode);

void SimpleNode::initialize()

{

msg = new cMessage(“dataMessage”);

if (getIndex() == 0) {  // Start from node 0

transmitData();

}

}

void SimpleNode::handleMessage(cMessage *msg)

{

if (msg == this->msg) {

// Transmit data to other nodes

transmitData();

} else {

// Handle received message (just print for now)

receiveData(msg);

}

}

void SimpleNode::transmitData()

{

// Randomly choose a neighboring node to send data to

int nextNode = (getIndex() + 1) % 5;  // Simple example: next node in the array (circular routing)

cMessage *newMsg = new cMessage(“data”);

send(newMsg, “out”, nextNode);  // Send to the next node

// Simulate periodic transmission

scheduleAt(simTime() + 1.0, msg);

}

 

void SimpleNode::receiveData(cMessage *msg)

{

EV << “Node ” << getIndex() << ” received message: ” << msg->getName() << “\n”;

delete msg;

}

SimpleNode::~SimpleNode()

{

cancelAndDelete(msg);

}

  1. Configure Simulation Parameters in omnetpp.ini

In the omnetpp.ini file, setting replicate parameters message interval, transmission delay, or network parameters. This file is core for controlling the replication behavior.

Example: omnetpp.ini

[General]

network = IrregularTopology

sim-time-limit = 100s

**.node*.msgInterval = 1s

**.node*.out.delay = 0.5s

  • **.node*.msgInterval sets a periodic message interval for each node.
  • **.node*.out.delay sets a delay for message transmission.
  1. Compile the Project

After we have generated the NED and C++ files, build your project in OMNeT++.

  1. Right-click on the project in the Project Explorer and choose the Build Project.
  2. OMNeT++ will compile the project and create the executable.
  1. Run the Simulation

After the build completes:

  1. Right-click on the project folder in Project Explorer and choose Run As > OMNeT++ Simulation.
  2. The Replication will start. During the replication, we can view on how messages are sent among the nodes according to the irregular connections we have defined.
  1. Visualize and Analyze Results

OMNeT++ delivers the many tools for envision and study for the replication outcomes:

  • Simulation GUI: Use the graphical user interface to envision the network, follow on packet flow, and checked the node states.
  • Result Analysis: Use scavetool to study the performance metrics such as packet delivery time, network throughput, or message delays.
  1. Extend the Simulation

We can additional improve the replication through adding:

  • Randomized Node Placement: If we need to design the irregular topologies in which nodes are placed in arbitrarily space, we can be used a modification arbitrary placement procedure.
  • Fault Tolerance and Failure Models: Launch the network failures, such as link or node failures; we examine the resilience of irregular topology.
  • Traffic Models: Research by several kinds of congestion design such as bursty traffic, constant bit rate, and random packet arrival and examine the network’s behavior below changing load conditions.
  • Routing Algorithms: Apply and validate the modification of routing procedures that take into account the irregular environment of the topology.

Conclusion

We initialize the Irregular Topology project in OMNeT++, we want to:

  1. Describe the network structure such as manually or randomly in NED files.
  2. Apply the modification of C++ behavior for nodes we maintain the packet transmission and reception.
  3. Setting the simulation parameters and process for the replication.
  4. Envision and examine the replication outcomes.

By following these steps, you can create various types of irregular network topologies, model realistic scenarios, and experiment with different network behaviors and protocols.

With the help of this procedure you can obtain the knowledge and can be able to simulate the Irregular Topology project in OMNeT++ tool. Additional detailed about the Irregular Topology project also provided.