How to Begin Implement Network Redundancy in NS3

To begin implementing and examining the Network Redundancy using NS3, we will need to adhere given structured approach. Network redundancy denotes the enclosure of additional modules, connections, or routes within a network, making sure that reliability, fault tolerance, and uninterrupted service in the course of failures. Following is a stepwise instruction to get started:

Steps to Begin Implement Network Redundancy in NS3

1. Understand Network Redundancy

Redundancy makes sure that the network can be persisted to function if one or more modules weaken. Fundamental forms of redundancy contain:

• Path Redundancy: Numerous paths among the source and destination node.
• Link Redundancy: Additional connections for avoiding the interaction failures.
• Node Redundancy: Backup nodes supports to manage the breakdowns.

2. Set Up Your Environment

We can install ns3 environment on the system. Make use of suitable components such as Point-to-Point, Wi-Fi, or LTE according to the redundancy situation.

3. Create the Network Topology

Example: Redundant Topology

Make a network topology including redundant routes among the source and destination nodes.

NodeContainer nodes;

nodes.Create(6); // 6 nodes for a redundant topology

PointToPointHelper pointToPoint;

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

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

// Create primary and redundant links

NetDeviceContainer devices;

devices.Add(pointToPoint.Install(nodes.Get(0), nodes.Get(1)));

devices.Add(pointToPoint.Install(nodes.Get(1), nodes.Get(2)));

devices.Add(pointToPoint.Install(nodes.Get(2), nodes.Get(3))); // Primary path

devices.Add(pointToPoint.Install(nodes.Get(0), nodes.Get(4))); // Redundant path

devices.Add(pointToPoint.Install(nodes.Get(4), nodes.Get(5)));

devices.Add(pointToPoint.Install(nodes.Get(5), nodes.Get(3))); // Redundant path

4. Install the Internet Stack

We will want to install internet stack to allow routing protocols using redundant paths.

InternetStackHelper stack;

stack.Install(nodes);

Ipv4AddressHelper address;

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

Ipv4InterfaceContainer interfaces = address.Assign(devices);

Manage the route discovery to leverage a dynamic routing protocol such as OLSR or AODV:

OlsrHelper olsr; // Proactive routing protocol

stack.SetRoutingHelper(olsr);

5. Generate Traffic

Replicate the traffic among source and destination, we can install applications.

Example: UDP Traffic

UdpEchoServerHelper echoServer(9);

ApplicationContainer serverApps = echoServer.Install(nodes.Get(3)); // Node 3 as server

serverApps.Start(Seconds(1.0));

serverApps.Stop(Seconds(10.0));

UdpEchoClientHelper echoClient(interfaces.GetAddress(3), 9);

echoClient.SetAttribute(“MaxPackets”, UintegerValue(1000));

echoClient.SetAttribute(“Interval”, TimeValue(Seconds(0.01))); // 10ms interval

echoClient.SetAttribute(“PacketSize”, UintegerValue(1024));    // 1KB packets

ApplicationContainer clientApps = echoClient.Install(nodes.Get(0)); // Node 0 as client

clientApps.Start(Seconds(2.0));

clientApps.Stop(Seconds(10.0));

6. Simulate Failures

Launch link or node failures to experiment the redundancy.

Example: Link Failure

Mimic a link failure within the main path:

Simulator::Schedule(Seconds(4.0), [&devices]() {

Ptr<PointToPointNetDevice> dev = DynamicCast<PointToPointNetDevice>(devices.Get(2).Get(0)); // Link Node 1 <-> Node 2

dev->SetReceiveCallback(MakeNullCallback<void, Ptr<NetDevice>, Ptr<const Packet>, uint16_t, const Address &>());

std::cout << “Link between Node 1 and Node 2 failed at time ” << Simulator::Now().GetSeconds() << “s\n”;

});

Example: Node Failure

Replicate a critical node’s failure:

Simulator::Schedule(Seconds(5.0), [&nodes]() {

nodes.Get(1)->GetObject<Ipv4>()->SetDown(); // Node 1 fails

std::cout << “Node 1 failed at time ” << Simulator::Now().GetSeconds() << “s\n”;

});

7. Monitor Redundancy Metrics

Measure Packet Loss

During the simulation, monitor the volume of packets that are dropped:

uint32_t packetsLost = 0;

void PacketDroppedCallback(Ptr<const Packet> packet) {

packetsLost++;

std::cout << “Packet dropped at time ” << Simulator::Now().GetSeconds() << “s\n”;

}

Ptr<Queue<Packet>> queue = StaticCast<PointToPointNetDevice>(devices.Get(0).Get(0))->GetQueue();

queue->TraceConnectWithoutContext(“Drop”, MakeCallback(&PacketDroppedCallback));

Measure Recovery Time

After failure, observe the duration for retrieving the traffic:

double recoveryStartTime = 0.0;

double recoveryEndTime = 0.0;

void RecoveryStartCallback() {

recoveryStartTime = Simulator::Now().GetSeconds();

std::cout << “Recovery started at time ” << recoveryStartTime << “s\n”;

}

void RecoveryEndCallback() {

recoveryEndTime = Simulator::Now().GetSeconds();

double recoveryTime = recoveryEndTime – recoveryStartTime;

std::cout << “Recovery completed at time ” << recoveryEndTime << “s\n”;

std::cout << “Recovery Time: ” << recoveryTime << ” seconds\n”;

}

Measure Throughput

Estimate the throughput during and after failures with the support of FlowMonitor:

FlowMonitorHelper flowmon;

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

Simulator::Stop(Seconds(10.0));

Simulator::Run();

monitor->CheckForLostPackets();

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

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

for (auto& flow : stats) {

double throughput = flow.second.rxBytes * 8.0 / (flow.second.timeLastRxPacket.GetSeconds() – flow.second.timeFirstTxPacket.GetSeconds());

std::cout << “Flow ” << flow.first << ” Throughput: ” << throughput / 1e6 << ” Mbps\n”;

}

8. Enable Tracing

ASCII and PCAP Tracing

Effectively make logs for in-depth analysis:

AsciiTraceHelper ascii;

pointToPoint.EnableAsciiAll(ascii.CreateFileStream(“network_redundancy.tr”));

pointToPoint.EnablePcapAll(“network_redundancy”);

XML Animation

Utilize NetAnim to envision the redundant paths and failure retrieval:

AnimationInterface anim(“network_redundancy.xml”);

9. Experiment with Parameters

• Redundant Links: Experiment various amounts of redundant links.
• Failure Scenarios: Replicate diverse link and node failures situations.
• Traffic Patterns: Examine how redundancy manages various kinds of traffic models.

10. Run the Simulation

At the end, we execute the simulation and then examine its outcomes in NS3:

Simulator::Run();

Simulator::Destroy();

With these steps, you can implement and analyze the Network Redundancy using NS3, allowing you to test with metrics, and measure redundancy parameters during the failure. Should you have any queries about this topic, please refer to the supplementary manual.