How to Calculate Network Number of alive nodes in omnet++
To calculate the number of alive nodes in OMNeT++, during the simulation, we need to find the status of every node. “Alive nodes” normally means the nodes which are operational and has potential of sending or receiving data. At omnet-manual.com, we help you understand how your network is doing by checking the number of active nodes in OMNeT++. With advice from an expert developer, we provide clear explanations to assist you.
Follow the guide to implement it in OMNeT++:
Step-by-Step Implementation:
- Define Node Status
We need to find whether the node is alive or not by defining a mechanism. It can be accomplished by presenting a Boolean variable in the node’s C++ class to signify the status.
- Initialize Node Status
In node’s initialization function, at the beginning of this simulation, we should configure all nodes to be alive.
bool isAlive;
void initialize() override {
isAlive = true; // Assume node is alive at start
}
- Update Node Status during Simulation
Throughout the simulation, you may have conditions under which a node might “die” (e.g., energy depletion, reaching a failure state, etc.). We need to keep posted the isAlive variable accordingly.
void handleMessage(cMessage *msg) override {
if (/* condition to check if node is dead */) {
isAlive = false;
} else {
// Normal message processing
}
}
- Implement Alive Node Count
In the simulation, we have to execute a method to count the number of nodes that have isAlive set to true which helps to calculate the number of alive nodes at any given point. It can done either occasionally or at the end in the simulation.
Periodic Checking (Using Self-Messages)
We can occasionally verify the number of alive nodes by scheduling a self-message.
void initialize() override {
isAlive = true;
scheduleAt(simTime() + checkInterval, new cMessage(“checkAliveNodes”));
}
void handleMessage(cMessage *msg) override {
if (msg->isSelfMessage()) {
countAliveNodes();
scheduleAt(simTime() + checkInterval, msg); // Reschedule
} else {
// Handle other messages
}
}
void countAliveNodes() {
int aliveNodeCount = 0;
for (int i = 0; i < getParentModule()->getSubmoduleVectorSize(“node”); i++) {
Node *node = check_and_cast<Node *>(getParentModule()->getSubmodule(“node”, i));
if (node->isAlive) {
aliveNodeCount++;
}
}
EV << “Number of alive nodes: ” << aliveNodeCount << endl;
}
- Collect and Analyze Alive Node Data
We have to record the counting of alive node by aggregating this data for post-simulation analysis as a statistic.
@statistic[aliveNodes](“Number of Alive Nodes”, vector, record=last);
In the node or network code, emit the statistic while counting alive nodes:
emit(aliveNodesSignal, aliveNodeCount);
- Run the Simulation
Run the simulation to track the number of alive nodes over time. Use in-built analysis tool of OMNeT++ to analyze the results or export them for further analysis.
Example Scenario
Here’s how this might look in a simple node module:
class SimpleNode : public cSimpleModule
{
private:
bool isAlive;
cMessage *checkMsg;
simsignal_t aliveNodesSignal;
protected:
virtual void initialize() override {
isAlive = true;
checkMsg = new cMessage(“checkAliveNodes”);
scheduleAt(simTime() + 1, checkMsg);
aliveNodesSignal = registerSignal(“aliveNodes”);
}
virtual void handleMessage(cMessage *msg) override {
if (msg == checkMsg) {
countAliveNodes();
scheduleAt(simTime() + 1, checkMsg);
} else {
// Handle other messages
}
}
void countAliveNodes() {
int aliveNodeCount = 0;
for (int i = 0; i < getParentModule()->getSubmoduleVectorSize(“node”); i++) {
SimpleNode *node = check_and_cast<SimpleNode *>(getParentModule()->getSubmodule(“node”, i));
if (node->isAlive) {
aliveNodeCount++;
}
}
emit(aliveNodesSignal, aliveNodeCount);
EV << “Number of alive nodes: ” << aliveNodeCount << endl;
}
};
- End Simulation and Collect Results
Finally, Make sure that we properly clean up any dynamically assigned memory and analyze the results once the simulation is completed.
This demonstration has all the essential information which is to know about the calculation of Network Number of Alive nodes in OMNeT++. We can also provide any details about alive nodes or how to calculate them using another simulation, if needed