To calculate the network connectivity robustness in OMNeT++ has needs to encompass calculating the network’s ability to maintain connections among nodes under numerous conditions, like node failures, link failures, or changes in network topology. It is a key metric for measuring the resilience of a network, especially in dynamic environments like mobile ad hoc networks (MANETs) or sensor networks.

**Steps to Calculate Network Connectivity Robustness in OMNeT++:**

**Define Connectivity Robustness Metric:****Connectivity Ratio:**The total number of nodes in the network is the ration of connected nodes.**Network Diameter:**The longest shortest path among any two nodes in the network.**Average Path Length:**The average of all shortest paths between nodes.**Percentage of Connected Components:**The percentage of the network that stays connected after node or link failures.

**Set Up the Network Model:**- Describe the network topology using NED files in OMNeT++. It contains setting up nodes, links, and routing protocols. The topology would reflect the network’s environment, like a static or dynamic scenario.

**Implement Node and Link Failures:**- Launch node and link failures to mimic real-world conditions where parts of the network may become disconnected. This can be done during the simulation using failure models or by manually deactivating nodes or links.

**Track Network Connectivity:**- Observe the network’s connectivity through the simulation. It includes verifying whether all nodes can still communicate with each other, either directly or over the multi-hop paths.

**Calculate Connectivity Robustness:****Connectivity Ratio:**Connectivity Ratio=Number of Connected NodesTotal Number of Nodes×100%\text{Connectivity Ratio} = \frac{\text{Number of Connected Nodes}}{\text{Total Number of Nodes}} \times 100\%Connectivity Ratio=Total Number of NodesNumber of Connected Nodes×100%**Network Diameter:**Use a graph traversal algorithm like Breadth-First Search (BFS) to calculate the longest shortest path between any two nodes.-
**Average Path Length:**Compute the average of all shortest paths between nodes. **Percentage of Connected Components:**Percentage of Connected Components=Number of Connected ComponentsTotal Number of Nodes×100%\text{Percentage of Connected Components} = \frac{\text{Number of Connected Components}}{\text{Total Number of Nodes}} \times 100\%Percentage of Connected Components=Total Number of NodesNumber of Connected Components×100%

**Example Implementation: Connectivity Ratio Calculation**

The following is an example of how to calculate the connectivity ratio in OMNeT++:

#include <omnetpp.h>

#include <vector>

#include <algorithm>

using namespace omnetpp;

class ConnectivityModule : public cSimpleModule {

private:

std::vector<bool> nodeStatus; // Track the status (connected/disconnected) of each node

int totalNodes;

int connectedNodes;

protected:

virtual void initialize() override {

totalNodes = par(“totalNodes”);

nodeStatus.resize(totalNodes, true); // Assume all nodes start as connected

// Schedule the first check for connectivity

scheduleAt(simTime() + par(“checkInterval”).doubleValue(), new cMessage(“checkConnectivity”));

}

virtual void handleMessage(cMessage *msg) override {

if (strcmp(msg->getName(), “checkConnectivity”) == 0) {

// Check the connectivity of all nodes

connectedNodes = std::count(nodeStatus.begin(), nodeStatus.end(), true);

// Calculate the connectivity ratio

double connectivityRatio = (double)connectedNodes / totalNodes * 100.0;

EV << “Connectivity Ratio: ” << connectivityRatio << “%\n”;

// Schedule the next connectivity check

scheduleAt(simTime() + par(“checkInterval”).doubleValue(), msg);

}

}

// Simulate a node failure (you would typically call this from another part of your simulation)

void simulateNodeFailure(int nodeId) {

if (nodeId >= 0 && nodeId < totalNodes) {

nodeStatus[nodeId] = false;

EV << “Node ” << nodeId << ” has failed and is now disconnected.\n”;

}

}

// Example of how you might determine if a node is connected

bool isNodeConnected(int nodeId) {

// This is a simple check; in a real scenario, you would need to perform graph traversal

return nodeStatus[nodeId];

}

};

Define_Module(ConnectivityModule);

**Explanation:**

**ConnectivityModule:****nodeStatus:**A vector that tracks whether each node is connected or disconnected. Primarily, all nodes are assumed to be connected.**handleMessage() Function:**Periodically calculates the connectivity ratio and checks the connectivity status of all nodes.**simulateNodeFailure() Function:**Mimics a node failure by marking the node as disconnected in the nodeStatus vector.

**Connectivity Ratio Calculation:**- The ratio is evaluated by counting the number of connected nodes and dividing it by the total number of nodes, then multiplying by 100 to get a percentage.

**Run the Simulation:**

- Compile and run the OMNeT++ project. The simulation will periodically calculate the connectivity ratio and check the connectivity of the network.

**Analyse and Interpret Results:**

- A high connectivity ratio shows that the network remains well-connected despite failures, while a low ratio recommends that the network is vulnerable to disconnections.
- The connectivity ratio gives a measure of the network’s robustness in maintaining connections among nodes.

**Additional Considerations:**

**Dynamic Topologies:**In dynamic networks like MANETs, where nodes often move or vary connections, consider executing a more sophisticated connectivity verify that accounts for dynamic topology changes.**Redundancy:**Assess the impact of redundancy, such as various paths or backup nodes, on the network’s connectivity robustness.**Failure Scenarios:**Simulate several failure scenarios like targeted attacks, random node failures to measure the network’s robustness under many conditions

In conclusion, we had execute how to calculate the Network Connectivity Robustness in OMNeT++. It is helps to calculate the network ability and maintain conditions between nodes. We will distribute added details about Network Connectivity Robustness in various tools.

Share the specifics of your project parameters so that we may assist you in evaluating the Network Connectivity Robustness using the OMNeT++ tool. We will conduct a comparative analysis and deliver precise results. Should you require suggestions for project implementation or comparative analysis, we are available to provide assistance in that regard.