How to Begin Implement Network Buffering in NS3

To begin implementing the network buffering using NS3, we will need to replicate the scenarios in which data packets are possessed in a buffer temporarily by reason of resource constraints like limited bandwidth or network congestion. Below is a detailed instruction to get started with executing the Network Buffering in NS3:

Steps to Begin Implement Network Buffering in NS3

1. Understand Network Buffering

• Buffering encompasses to queue packets on the node or device before sending them.
• Buffers are frequently connected with:
  • Network Queues: DropTail, RED, CoDel, and so on.
  • Router Buffers: Buffers functioning at intermediate network devices.
  • Endpoint Buffers: It buffers on the sender or receiver nodes.

2. Set Up ns3

• We should download and set up the ns3 simulator on the computer:

./waf configure –build-profile=debug –enable-examples –enable-tests

./waf build

• Confirm the installation by executing:

./waf –run hello-simulator

3. Familiarize Yourself with Buffer Models in ns3

NS3 offers numerous schemes of queue management like:

• DropTailQueue: If occupied, then FIFO buffer in which packets are lost.
• REDQueue (Random Early Detection): It probabilistically stops the packets before the queue is filled.
• CoDelQueue (Controlled Delay): Reduces the buffer bloat and latency.

4. Set Up a Simulation Scenario

Make a simple network topology to experiment the network buffering.

Example: Topology

• Two nodes are associated through a point-to-point link.
• Set up the connection including a limited bandwidth and buffer size.

#include “ns3/core-module.h”

#include “ns3/network-module.h”

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

#include “ns3/traffic-control-module.h”

#include “ns3/applications-module.h”

using namespace ns3;

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

{

Time::SetResolution(Time::NS);

// Create nodes

NodeContainer nodes;

nodes.Create(2);

// Configure point-to-point link

PointToPointHelper pointToPoint;

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

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

// Install devices

NetDeviceContainer devices;

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);

// Configure traffic control with buffering

TrafficControlHelper tch;

tch.SetRootQueueDisc(“ns3::DropTailQueueDisc”, “MaxSize”, StringValue(“10p”));

QueueDiscContainer qdiscs = tch.Install(devices);

// Set up traffic generator

uint16_t port = 9;

UdpServerHelper server(port);

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

serverApps.Start(Seconds(1.0));

serverApps.Stop(Seconds(10.0));

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

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

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

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

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

clientApps.Start(Seconds(2.0));

clientApps.Stop(Seconds(10.0));

// Enable queue tracing

Ptr<QueueDisc> queue = qdiscs.Get(0);

queue->TraceConnectWithoutContext(“Enqueue”, MakeCallback([](Ptr<const QueueDiscItem> item) {

NS_LOG_UNCOND(“Packet enqueued at: ” << Simulator::Now().GetSeconds() << ” seconds”);

}));

queue->TraceConnectWithoutContext(“Dequeue”, MakeCallback([](Ptr<const QueueDiscItem> item) {

NS_LOG_UNCOND(“Packet dequeued at: ” << Simulator::Now().GetSeconds() << ” seconds”);

}));

queue->TraceConnectWithoutContext(“Drop”, MakeCallback([](Ptr<const QueueDiscItem> item) {

NS_LOG_UNCOND(“Packet dropped at: ” << Simulator::Now().GetSeconds() << ” seconds”);

}));

// Run simulation

Simulator::Run();

Simulator::Destroy();

return 0;

}

5. Configure Buffer Parameters

• Fine-tune buffer size and behavior:

tch.SetRootQueueDisc(“ns3::DropTailQueueDisc”, “MaxSize”, StringValue(“20p”)); // 20 packets

• Make use of other queue types:

tch.SetRootQueueDisc(“ns3::RedQueueDisc”);

6. Monitor Buffering Behavior

• Traces: Record enqueues, dequeues, and drops utilising callbacks.
• FlowMonitor: Examine the performance of end-to-end:

FlowMonitorHelper flowmonHelper;

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

monitor->SerializeToXmlFile(“buffering-analysis.xml”, true, true);

7. Run the Simulation

Construct the script and then run the simulation:

./waf –run scratch/buffering-simulation

8. Analyze Results

• Packet Drops: Verify how many packets are lost by reason of buffer overflow.
• Queuing Delay: Estimate the duration of packets, which expend within the buffer.
• Throughput and Latency: Examine the influence of buffering on network performance.

We have delivered a clear and step-by-step guide that comprises of numerous steps with sample coding to implement the Network Buffering and examine the outcomes using NS3 tool. We are ready to offer more advanced information as needed.