How to Calculate Network Time Delay in ns3

To calculate time delay (latency) in ns3, we need to measure the time taken for a packet to travel from the source node to the destination node. For evaluating the performance of network protocols and applications, time delay can be an important metric. We can calculate time delay by simulating data transmission, collect packet delay information, and calculate the time delay.

Here is a complete guide on this.

Steps for calculation

1. Set up your ns3 :

• Make sure that ns3 is installed in the computer. If not, install it.

2. Create a new ns3 script :

• In the scratch directory of ns3, create a new script.

3. Include necessary libraries :

• In your script, include the necessary libraries.

4. Define network topology :

• For your network topology, create multiple nodes.

5. Implement time delay Calculation Logic :

• To measure the time delay of packets, use packet tags or tracing callbacks.

Example for calculating time delay in ns3

Here is the example for the calculation of time delay :

#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”

#include “ns3/flow-monitor-module.h”

using namespace ns3;

NS_LOG_COMPONENT_DEFINE (“TimeDelayCalculationExample”);

void PacketReceiveCallback(Ptr<FlowMonitor> monitor, Ptr<Ipv4FlowClassifier> classifier)

{

FlowMonitor::FlowStatsContainer stats = monitor->GetFlowStats();

for (auto it = stats.begin(); it != stats.end(); ++it)

{

Ipv4FlowClassifier::FiveTuple t = classifier->FindFlow(it->first);

if (t.destinationPort == 9) // Assuming UDP Echo Server is using port 9

{

double avgDelay = it->second.delaySum.GetSeconds() / it->second.rxPackets;

std::cout << “Average Delay: ” << avgDelay << ” seconds” << std::endl;

}

}

}

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

{

uint32_t nNodes = 2; // Number of nodes

double simulationTime = 10.0; // Total simulation time in seconds

CommandLine cmd;

cmd.AddValue(“nNodes”, “Number of nodes”, nNodes);

cmd.AddValue(“simulationTime”, “Total simulation time”, simulationTime);

cmd.Parse(argc, argv);

NodeContainer nodes;

nodes.Create(nNodes);

PointToPointHelper pointToPoint;

pointToPoint.SetDeviceAttribute(“DataRate”, StringValue(“5Mbps”));

pointToPoint.SetChannelAttribute(“Delay”, StringValue(“2ms”));

NetDeviceContainer devices;

devices = pointToPoint.Install(nodes);

InternetStackHelper stack;

stack.Install(nodes);

Ipv4AddressHelper address;

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

Ipv4InterfaceContainer interfaces = address.Assign(devices);

uint16_t port = 9;

UdpEchoServerHelper echoServer(port);

ApplicationContainer serverApps = echoServer.Install(nodes.Get(1));

serverApps.Start(Seconds(1.0));

serverApps.Stop(Seconds(simulationTime));

UdpEchoClientHelper echoClient(interfaces.GetAddress(1), port);

echoClient.SetAttribute(“MaxPackets”, UintegerValue(100));

echoClient.SetAttribute(“Interval”, TimeValue(Seconds(0.1)));

echoClient.SetAttribute(“PacketSize”, UintegerValue(1024));

ApplicationContainer clientApps = echoClient.Install(nodes.Get(0));

clientApps.Start(Seconds(2.0));

clientApps.Stop(Seconds(simulationTime));

FlowMonitorHelper flowmonHelper;

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

Ptr<Ipv4FlowClassifier> classifier = DynamicCast<Ipv4FlowClassifier>(flowmonHelper.GetClassifier());

Simulator::Stop(Seconds(simulationTime));

Simulator::Run();

PacketReceiveCallback(monitor, classifier);

Simulator::Destroy();

return 0;

}

Explanation

1. Nodes and links :

Nodes are created. Point-to-point links between nodes are configured. Set up the network with nodes connected using point-to-point links.

2. Applications :

On one node, a UDP echo server is installed. and On another node, a UDP echo server is installed to generate traffic.

3. Flow monitor :

To collect data on packet transmissions, including delay, used the FlowMonitor module.

4. Packet receiver callback :

To calculate the average delay by dividing the total delay by the number of received packets,  PacketReceiveCallback is implemented.

5. Running the Simulation :

The simulation runs collecting data using FlowMonitor. Average delay is calculated and printed, after the simulation.

Overall, we had successfully calculated time delay in ns3 by measuring the time taken for a packet to travel from the source node to the destination node. Also, we provide more related information on time delay.

Do you wish to seek further assistance in the area of performance analysis, specifically on calculating time delay in ns3, share your requirements with our team. At ns3simulation.com, we are committed to delivering an in-depth analysis of the outcomes.