How to Begin Implement Network Stability Index in NS3

To begin implementing a Network Stability Index (NSI) using NS3 that needs to estimate and measure the reliability and robustness in diverse network conditions. NSI is specifically leveraged to examine the networks including dynamic topologies like wireless or mobile networks in which stability is impacted by factors such as node mobility, link failures, and congestion. Below is a structured mechanism to execute the Network Stability Index using NS3:

Steps to Implement Network Stability Index in NS3

1. Understand the Network Stability Index

• Definition: NSI estimates how constantly a network can be sustained the connectivity and effectively distributed data over time.
• Metrics:
  • Packet Delivery Ratio (PDR): Percentage of packets that are effectively distributed to transmitted packets.
  • Link Stability: Time period in the course of which a link among the nodes stays dynamic.
  • Node Connectivity: Rate of node’s time is accessible.
  • Stability Index: A weighted mixture of parameters such as PDR, link stability, and node connectivity.

2. Set Up NS3 Simulation Environment

1. Install NS3:
   • Make sure that we have installed NS3 and properly functioning. Also, we can download it.
2. Define a Network Topology:
   • Make a network topology related to the scenario like a wireless ad hoc network, a mobile network, or a static wired network.

3. Define Metrics for Stability

Choose the performance parameters for estimating the NSI. For instance:

1. Packet Delivery Ratio (PDR): PDR=Packets DeliveredPackets Sent\text{PDR} = \frac{\text{Packets Delivered}}{\text{Packets Sent}}PDR=Packets SentPackets Delivered​
2. Link Stability: Compute the time period of dynamic links.
3. Node Connectivity: Assess the rate of node’s time stays linked to the network.

4. Implement NSI Calculation

Here’s an instance of NS3 script, which determines NSI according to the PDR and link stability.

Example Script: Network Stability Index in NS3

#include “ns3/core-module.h”

#include “ns3/network-module.h”

#include “ns3/internet-module.h”

#include “ns3/point-to-point-module.h”

#include “ns3/mobility-module.h”

#include “ns3/applications-module.h”

using namespace ns3;

class StabilityIndexCalculator {

public:

StabilityIndexCalculator() : m_packetsSent(0), m_packetsDelivered(0), m_totalLinkDuration(0.0), m_activeLinks(0) {}

void PacketSent() {

m_packetsSent++;

}

void PacketDelivered() {

m_packetsDelivered++;

}

void LinkActive() {

m_activeLinks++;

}

void LinkInactive(Time duration) {

m_totalLinkDuration += duration.GetSeconds();

m_activeLinks–;

}

void CalculateStabilityIndex(Time totalTime) {

double pdr = static_cast<double>(m_packetsDelivered) / m_packetsSent;

double averageLinkStability = m_totalLinkDuration / totalTime.GetSeconds();

double stabilityIndex = (0.7 * pdr) + (0.3 * averageLinkStability); // Weighted combination

NS_LOG_UNCOND(“Stability Index: ” << stabilityIndex);

NS_LOG_UNCOND(“PDR: ” << pdr << “, Average Link Stability: ” << averageLinkStability);

}

private:

uint32_t m_packetsSent;

uint32_t m_packetsDelivered;

double m_totalLinkDuration;

uint32_t m_activeLinks;

};

StabilityIndexCalculator stabilityCalculator;

void SentPacketCallback(Ptr<const Packet> packet) {

stabilityCalculator.PacketSent();

}

void ReceivedPacketCallback(Ptr<const Packet> packet) {

stabilityCalculator.PacketDelivered();

}

void SimulateLinkActivity(NodeContainer nodes, Ptr<NetDevice> device, Time activeTime, Time inactiveTime) {

Simulator::Schedule(activeTime, &StabilityIndexCalculator::LinkActive, &stabilityCalculator);

Simulator::Schedule(activeTime + inactiveTime, &StabilityIndexCalculator::LinkInactive, &stabilityCalculator, inactiveTime);

}

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

CommandLine cmd;

cmd.Parse(argc, argv);

// Create nodes

NodeContainer nodes;

nodes.Create(2);

// Configure Point-to-Point link

PointToPointHelper pointToPoint;

pointToPoint.SetDeviceAttribute(“DataRate”, StringValue(“10Mbps”));

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

NetDeviceContainer devices = pointToPoint.Install(nodes);

// Install Internet stack

InternetStackHelper stack;

stack.Install(nodes);

// Assign IP addresses

Ipv4AddressHelper address;

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

Ipv4InterfaceContainer interfaces = address.Assign(devices);

// Install applications

uint16_t port = 9;

UdpEchoServerHelper server(port);

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

serverApp.Start(Seconds(1.0));

serverApp.Stop(Seconds(10.0));

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

client.SetAttribute(“MaxPackets”, UintegerValue(50));

client.SetAttribute(“Interval”, TimeValue(MilliSeconds(200)));

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

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

clientApp.Start(Seconds(2.0));

clientApp.Stop(Seconds(10.0));

// Attach callbacks

devices.Get(0)->TraceConnectWithoutContext(“PhyTxEnd”, MakeCallback(&SentPacketCallback));

devices.Get(1)->TraceConnectWithoutContext(“PhyRxEnd”, MakeCallback(&ReceivedPacketCallback));

// Simulate link activity

SimulateLinkActivity(nodes, devices.Get(1), Seconds(3.0), Seconds(5.0)); // Link active for 3s, inactive for 5s

// Schedule stability index calculation

Simulator::Schedule(Seconds(10.0), &StabilityIndexCalculator::CalculateStabilityIndex, &stabilityCalculator, Seconds(10.0));

Simulator::Run();

Simulator::Destroy();

return 0;

}

Explanation of the Script

1. Stability Metrics:
   • The StabilityIndexCalculator class monitors the PDR and link stability.
   • It integrates these parameters to leverage weighted factors for estimating the NSI.
2. Packet Tracking:
   • Apply callbacks to monitor the packet transmissions and receptions.
3. Link Activity Simulation:
   • The SimulateLinkActivity function allows and inactivates connections for replicating the network instability.
4. Stability Index Calculation:
   • According to the PDR and average link stability, the stability index is computed.

5. Run the Simulation

1. Build the script:

./waf –run “your-script-name”

1. Monitor the results for computing the stability index, PDR, and link stability parameters.

6. Advanced Extensions

1. Dynamic Topologies:
   • Experiment the stability within mobile networks using mobility patterns.
2. Additional Metrics:
   • Add other parameters such as jitter, latency, or energy consumption in the NSI.
3. Multiple Links:
   • Prolong the simulation with multi-hop networks and then observe the link stability through paths.
4. Visualization:
   • Transfer outcomes into external tools such as Python, MATLAB, or Excel for graphical analysis.

In this manual, we had shared thorough methodology for implementing and analysing the Network Stability Index using NS3 environment. We are available to extend on it for your advanced knowledge.