To calculate and analyze network scalability in ns3, we need to measure performance metrics like throughput, latency, packet loss, and resource utilization as the number of nodes or traffic load increases. By simulating the network in varying sizes and loads we can understand how well the increasing demand will handled by network. Here the steps given below will guide on how to calculate the Network scalability in ns3.

Step-by-step to Calculate Network Scalability in ns3:

1. Set Up the NS3 Environment:
   • Make sure ns3 is installed.
2. Define the Network Topology:
   • Create a network topology that can be easily scaled, such as a star, mesh, or tree topology.
3. Install Applications:
   • Install traffic-generating applications on the nodes to simulate network traffic.
4. Measure Performance Metrics:
   • Use trace sources or callbacks to monitor performance metrics such as throughput, latency, and packet loss.
5. Scale the Network:
   • Gradually increase the number of nodes or the traffic load and measure the performance metrics at each step.
6. Analyze Scalability:
   • Compare the performance metrics as the network scales to determine its scalability.

Example Code

Here an example provided to guide on how to analyze network scalability by measuring throughput and latency as the number of nodes increases in a point-to-point network in ns3 simulation.

#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 (“NetworkScalabilityExample”);

void MeasurePerformance(Ptr<FlowMonitor> flowMonitor, FlowMonitorHelper& flowHelper, uint32_t nNodes)

{

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

std::map<FlowId, FlowMonitor::FlowStats> stats = flowMonitor->GetFlowStats ();

double totalThroughput = 0.0;

double totalLatency = 0.0;

uint32_t totalPackets = 0;

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

{

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

double throughput = it->second.rxBytes * 8.0 / (it->second.timeLastRxPacket.GetSeconds () – it->second.timeFirstTxPacket.GetSeconds ()) / 1024; // in kbps

double latency = it->second.delaySum.GetSeconds () / it->second.rxPackets * 1000; // in ms

totalThroughput += throughput;

totalLatency += latency;

totalPackets += it->second.rxPackets;

}

double averageLatency = totalPackets > 0 ? totalLatency / totalPackets : 0;

NS_LOG_UNCOND (“Number of Nodes: ” << nNodes);

NS_LOG_UNCOND (“Total Throughput: ” << totalThroughput << ” kbps”);

NS_LOG_UNCOND (“Average Latency: ” << averageLatency << ” ms”);

}

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

{

CommandLine cmd;

uint32_t maxNodes = 20;

cmd.AddValue (“maxNodes”, “Maximum number of nodes to simulate”, maxNodes);

cmd.Parse (argc, argv);

for (uint32_t nNodes = 2; nNodes <= maxNodes; ++nNodes)

{

NodeContainer nodes;

nodes.Create (nNodes);

PointToPointHelper pointToPoint;

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

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

InternetStackHelper stack;

stack.Install (nodes);

Ipv4AddressHelper address;

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

for (uint32_t i = 0; i < nNodes – 1; ++i)

{

NodeContainer p2pNodes = NodeContainer (nodes.Get (i), nodes.Get (i + 1));

NetDeviceContainer devices = pointToPoint.Install (p2pNodes);

address.Assign (devices);

address.NewNetwork ();

}

// Create UDP applications

UdpServerHelper server (9);

ApplicationContainer serverApp = server.Install (nodes.Get (nNodes – 1));

serverApp.Start (Seconds (1.0));

serverApp.Stop (Seconds (10.0));

UdpClientHelper client (Ipv4Address (“10.1.1.1”), 9);

client.SetAttribute (“MaxPackets”, UintegerValue (320));

client.SetAttribute (“Interval”, TimeValue (MilliSeconds (10)));

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

ApplicationContainer clientApp = client.Install (nodes.Get (0));

clientApp.Start (Seconds (2.0));

clientApp.Stop (Seconds (10.0));

FlowMonitorHelper flowHelper;

Ptr<FlowMonitor> flowMonitor = flowHelper.InstallAll ();

Simulator::Stop (Seconds (11.0));

Simulator::Run ();

MeasurePerformance (flowMonitor, flowHelper, nNodes);

Simulator::Destroy ();

}

return 0;

}

Explanation

1. Setup: The code sets up a scalable point-to-point network where nodes are connected in a linear topology.
2. Applications: A UDP server is installed on the last node, and a UDP client is installed on the first node to generate traffic.
3. Flow Monitor: The FlowMonitor is used to gather performance metrics like throughput and latency.
4. MeasurePerformance Function: This function calculates the total throughput and average latency for the network and logs the results.
5. Scaling the Network: The simulation runs in a loop, gradually increasing the number of nodes from 2 up to a specified maximum number of nodes.

Running the Simulation

Compile and run the simulation using the following commands in ns3 environment:

./waf configure

./waf build

./waf –run your-script-name

Replace your-script-name with the actual name of the script file.

Finally, the Network Scalability solution in ns3 calculated and analyzed  by measuring the performance of metrics like throughput, latency, packet loss and resource utilization  to determine how well the network can handle increasing demand.

For calculating the Network Scalability Solutions in Ns3 of your project you can follow the above steps. if you face any issues in throughput, latency, packet loss, or a combination of these factors you can drop us your parameters we will give you best results.