How to Calculate Network Throughput in omnet++

To calculate network throughput in OMNeT++ has includes evaluating the amount of data successfully transmitted across a network link or among the network nodes over a particular period and the term Throughput is commonly termed in bits per second (bps) or megabits per second (Mbps).

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Below are the procedures on how to implement the network throughput in OMNeT++:

Steps to Calculate Network Throughput in OMNeT++:

1. Set Up the Network Model:
   • Describe the network topology using NED files in OMNeT++ and contains to generate nodes such as clients and servers and connecting them with links that have specified data rates that has 100 Mbps.
2. Implement Traffic Generation:
   • Use or generate modules to create traffic, like UdpApp, TcpApp, or custom traffic generators. This traffic mimic data flows across the network.
   • Make sure the traffic generation reflects the type of service that are used to measure for throughput like continuous streaming, bulk data transfer.
3. Measure the Amount of Data Received:
   • To compute throughput, we need to evaluate the total amount of data (in bits) that has been successfully received at the destination over a particular period.
4. Calculate Throughput:
   • Throughput is computed by dividing the total amount of data received by the time period over which it was received: Throughput=Total Data Received (in bits)Time (in seconds)\text{Throughput} = \frac{\text{Total Data Received (in bits)}}{\text{Time (in seconds)}}Throughput=Time (in seconds)Total Data Received (in bits)​

Example Implementation:

Below is the sample of how to calculate throughput for a point-to-point network in OMNeT++:

#include <omnetpp.h>

using namespace omnetpp;

class ThroughputModule : public cSimpleModule {

private:

int64_t totalBitsReceived;  // Total number of bits received

simtime_t startTime;        // Start time of the measurement period

simtime_t endTime;          // End time of the measurement period

protected:

virtual void initialize() override {

totalBitsReceived = 0;

startTime = simTime();

endTime = 0;

// Schedule first packet send (if generating traffic)

// scheduleAt(simTime() + par(“sendInterval”).doubleValue(), new cMessage(“send”));

}

virtual void handleMessage(cMessage *msg) override {

if (!msg->isSelfMessage()) {

// Packet received

int packetSize = msg->getByteLength(); // Packet size in bytes

totalBitsReceived += packetSize * 8;   // Convert to bits

// Update the time of the last received packet

endTime = simTime();

delete msg;

}

}

virtual void finish() override {

// Calculate the time period over which the data was received

simtime_t timePeriod = endTime – startTime;

// Calculate and print throughput

double throughput = totalBitsReceived / timePeriod.dbl(); // in bits per second (bps)

EV << “Total Data Received: ” << totalBitsReceived << ” bits\n”;

EV << “Time Period: ” << timePeriod << ” seconds\n”;

EV << “Calculated Throughput: ” << throughput / 1e6 << ” Mbps\n”;

}

};

Define_Module(ThroughputModule);

Explanation:

• initialize() Function:
  • Initializes the variables totalBitsReceived, startTime, and endTime. These variables track the amount of data received and the time period over which it is received.
• handleMessage() Function:
  • Monitor incoming packets by updating the totalBitsReceived variable with the size of each packet received.
  • Updates endTime with the simulation time when the last packet is received.
• finish() Function:
  • At the end of the simulation, this function computes the throughput by dividing the total bits received by the duration of the time period.
  • The throughput is then logged in bits per second (bps) and converted to Mbps for easier interpretation.

5. Run the Simulation:

• Compile OMNeT++ project and run the simulation.
• After the simulation completes, inspect the console output or logs to view the calculated throughput.

6. Analyse and Interpret Results:

• The computed throughput delivers insight into the network’s ability to manage data traffic.
• Compare the measured throughput with the theoretical maximum throughput of the link to determine if the network is execution proficiently or if there are bottlenecks.

Additional Considerations:

• Traffic Type: The type of traffic has TCP, UDP and its characteristics like packet size, inter-arrival time can considerably impact the measured throughput.
• Network Conditions: Factors like congestion, packet loss, and delay can influence the actual throughput observed during the simulation.
• Link Characteristics: Make sure that the data rate of the links (data rate attribute in the NED file) is set properly to reflect the network’s capacity.

We demonstrate and provide the valuable insights on how to calculate and simulate the results using the OMNeT++ tool. If you need more details regarding the network throughput we will provide it.