How to Calculate Network Buffer Length in ns3

To calculate the network buffer length in ns3, need to trace the queue size of the network devices in the period of simulation.

Below are the detailed procedures on how to implement network buffer length in ns3:

Step-by-Step Guide to Calculate Network Buffer Length in ns3

1. Set Up the Simulation Environment:
   • Download the ns3 in the computer.
   • Take account of required modules in the simulation (e.g., Internet, PointToPoint).
2. Create Network Topology:
   • Define nodes, devices, and channels.
   • Set up IP addressing and routing.
3. Configure Applications:
   • Install traffic generating applications (e.g., UDP, TCP) on the nodes.
4. Configure Queue Disc:
   • Configure the queue discipline for the network devices (e.g., DropTail, CoDel).
5. Enable Tracing for Queue Length:
   • Enable tracing to capture the queue length during the simulation.
6. Run the Simulation:
   • Execute the simulation and collect the trace data.
7. Analyze the Results:
   • Post-process the trace data to calculate the buffer length over time.

Example Code Snippet

Here are the illustrative on how to setup simple point-to-point network, generate traffic, and monitor the queue length:

#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/queue-disc-module.h”

using namespace ns3;

NS_LOG_COMPONENT_DEFINE (“BufferLengthExample”);

// Function to log the queue length

void QueueLengthLogger (Ptr<QueueDisc> queue)

{

uint32_t qSize = queue->GetNPackets ();

NS_LOG_UNCOND (“Time: ” << Simulator::Now ().GetSeconds () << “s, Queue Length: ” << qSize << ” packets”);

Simulator::Schedule (Seconds (0.1), &QueueLengthLogger, queue); // Schedule the function to be called again

}

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

{

// Set up logging

LogComponentEnable (“UdpEchoClientApplication”, LOG_LEVEL_INFO);

LogComponentEnable (“UdpEchoServerApplication”, LOG_LEVEL_INFO);

// Create nodes

NodeContainer nodes;

nodes.Create (2);

// Set up point-to-point connection

PointToPointHelper pointToPoint;

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

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

// Install devices and channels

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);

// Set up UDP server on node 1

UdpEchoServerHelper echoServer (9);

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

serverApps.Start (Seconds (1.0));

serverApps.Stop (Seconds (10.0));

// Set up UDP client on node 0

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

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

echoClient.SetAttribute (“Interval”, TimeValue (Seconds (0.1)));

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

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

clientApps.Start (Seconds (2.0));

clientApps.Stop (Seconds (10.0));

// Install QueueDisc

QueueDiscContainer qdiscs;

TrafficControlHelper tch;

tch.SetRootQueueDisc (“ns3::CoDelQueueDisc”); // Using CoDel queue discipline

qdiscs = tch.Install (devices);

// Schedule Queue Length Logger

Simulator::Schedule (Seconds (0.1), &QueueLengthLogger, qdiscs.Get (0));

// Run the simulation

Simulator::Stop (Seconds (11.0));

Simulator::Run ();

Simulator::Destroy ();

return 0;

}

Explanation:

1. Setup Logging:
   • Enable logging for the UDP applications to track their activities.
2. Create Nodes and Network:
   • Two nodes connected with a point-to-point link.
   • Configure the link’s data rate and delay.
3. Install Network Stack:
   • Install the Internet stack on both nodes.
   • Assign IP addresses to the devices.
4. Configure Applications:
   • Install a UDP echo server on node 1.
   • Install a UDP echo client on node 0, configured to send packets to the server.
5. Install Queue Discipline:
   • Use the TrafficControlHelper to install a queue discipline (e.g., CoDel) on the devices.
6. Queue Length Logger:
   • Define a function to log the queue length periodically.
   • Schedule this function to run at regular intervals during the simulation.
7. Run Simulation:
   • Run the simulation for the specified duration.
8. Calculate Queue Length:
   • The queue length is logged periodically during the simulation.

Analysing the Results:

• The queue length logger function logs the queue length at regular intervals (every 0.1 seconds in this example).
• The log output can be analyzed to understand how the queue length (buffer length) changes over time.

We had learned and understand how the queue length logged periodically during the simulation with ns3. Here, we support and help further details about how the Network Buffer Length will simulated in other tools.

Comparative analysis on all areas of Network Buffer Length with best project guidance are assisted by ns3simulation.com.