How to Begin Implement Network Capacity in NS3

To begin implementing and analysing the Network Capacity in NS3, we follow these structured steps. Network capacity signifies the maximum data rate of network that can be supported whereas sustaining the adequate performance parameters like low latency and minimal packet loss.  Here’s a detailed procedure on how to implement the Network Capacity using NS3.

Steps to Begin Implement Network Capacity in NS3

1. Understand Network Capacity

Network capacity typically functions based on:

• Link bandwidth: The data rate of individual connections.
• Topology: The organization of nodes and links.
• Traffic patterns: The data flow type, amount, and direction.
• Protocol efficiency: The overhead launched with routing and interaction protocols.

Performance parameters for examining the network capacity:

• Throughput: Estimate the total volume of data that are effectively sent.
• Packet loss: Measure the rate of packets which are dropped when traffic maximizes.
• Latency: The delay undergone by ability of traffic load methods.

2. Set Up Your Environment

Make sure that we have installed ns3 and properly working on the system. Make acquainted about the simple ns3 scripting.

3. Create a Network Topology

Example: Point-to-Point Topology

NodeContainer nodes;

nodes.Create(2);

PointToPointHelper pointToPoint;

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

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

NetDeviceContainer devices;

devices = pointToPoint.Install(nodes);

Example: Wireless Topology

YansWifiChannelHelper channel = YansWifiChannelHelper::Default();

YansWifiPhyHelper phy = YansWifiPhyHelper::Default();

phy.SetChannel(channel.Create());

WifiHelper wifi;

wifi.SetStandard(WIFI_PHY_STANDARD_80211n);

WifiMacHelper mac;

mac.SetType(“ns3::AdhocWifiMac”);

NodeContainer wifiNodes;

wifiNodes.Create(5);

NetDeviceContainer wifiDevices;

wifiDevices = wifi.Install(phy, mac, wifiNodes);

4. Set Up the Internet Stack

We can install the Internet stack for IP-based interaction:

InternetStackHelper stack;

stack.Install(nodes);

Ipv4AddressHelper address;

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

Ipv4InterfaceContainer interfaces = address.Assign(devices);

5. Generate Traffic

Make applications for replicating the network traffic.

Example: Bulk TCP Traffic

uint16_t port = 9;

Address serverAddress(InetSocketAddress(interfaces.GetAddress(1), port));

BulkSendHelper bulkSender(“ns3::TcpSocketFactory”, serverAddress);

bulkSender.SetAttribute(“MaxBytes”, UintegerValue(0)); // Unlimited data

ApplicationContainer senderApps = bulkSender.Install(nodes.Get(0));

senderApps.Start(Seconds(1.0));

senderApps.Stop(Seconds(10.0));

PacketSinkHelper sink(“ns3::TcpSocketFactory”, serverAddress);

ApplicationContainer sinkApps = sink.Install(nodes.Get(1));

sinkApps.Start(Seconds(1.0));

sinkApps.Stop(Seconds(10.0));

Example: UDP Traffic

UdpEchoServerHelper echoServer(9);

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

serverApps.Start(Seconds(1.0));

serverApps.Stop(Seconds(10.0));

UdpEchoClientHelper echoClient(interfaces.GetAddress(1), 9);

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

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

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

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

clientApps.Start(Seconds(2.0));

clientApps.Stop(Seconds(10.0));

6. Increase Traffic Load

For analyzing the network capacity, we need to progressively maximize the intensity of traffic:

• Maximize the amount of transmitting nodes.
• Enlarge packet size or broadcasting rate.

Example:

UdpEchoClientHelper echoClient(interfaces.GetAddress(1), 9);

echoClient.SetAttribute(“Interval”, TimeValue(Seconds(0.001))); // 1ms interval

7. Measure Network Capacity

Using FlowMonitor

Estimate the performance parameters such as throughput, packet loss, and delay utilising 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) {

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

std::cout << “Flow ID: ” << flow.first << ” (” << t.sourceAddress << ” -> ” << t.destinationAddress << “)\n”;

std::cout << ”  Throughput: ” << flow.second.rxBytes * 8.0 / (flow.second.timeLastRxPacket.GetSeconds() – flow.second.timeFirstTxPacket.GetSeconds()) / 1e6 << ” Mbps\n”;

std::cout << ”  Packet Loss Ratio: ”

<< (flow.second.txPackets – flow.second.rxPackets) * 100.0 / flow.second.txPackets << “%\n”;

std::cout << ”  Average Delay: ” << flow.second.delaySum.GetSeconds() / flow.second.rxPackets << “s\n”;

}

Manual Throughput Calculation

Observe the packets that are transmitting and inherited to manually compute the throughput:

uint32_t packetsSent = 0, packetsReceived = 0;

void PacketSentCallback(Ptr<const Packet> packet) {

packetsSent++;

}

void PacketReceivedCallback(Ptr<const Packet> packet) {

packetsReceived++;

}

devices.Get(0)->TraceConnectWithoutContext(“MacTx”, MakeCallback(&PacketSentCallback));

devices.Get(1)->TraceConnectWithoutContext(“MacRx”, MakeCallback(&PacketReceivedCallback));

Towards the end of the replication:

Simulator::Schedule(Seconds(10.0), [] {

double throughput = (packetsReceived * 8.0 * 1024) / (10.0 * 1e6); // Mbps

std::cout << “Throughput: ” << throughput << ” Mbps\n”;

});

8. Visualize Results

• Envision the network leveraging NetAnim:

AnimationInterface anim(“network_capacity.xml”);

• Transfer outcomes into a file using tools such as MATLAB or Excel for graphical analysis.

9. Experiment and Optimize

• Experiment with various topologies like star, mesh, or grid.
• Make use of diverse routing protocols such as OLSR, AODV.
• Replicate the failures (e.g., node/link) to observe its influence over capacity.

10. Run the Simulation

Now, execute the simulation and then examine the network performance:

Simulator::Run();

Simulator::Destroy();

Throughout this manual, detailed guideline for executing and analyzing the Network Capacity using NS3 has been provided effectively. Additional information can be shared on this topic if required.