How to Implement Network Traffic Control in ns3

To implement the network traffic control in ns3 has encompasses to simulate the network and we need to control traffic flows by various queue disciplines, rate limiting, and traffic shaping mechanisms. Here, we provide the procedures to setting up a simple network and applying traffic control mechanisms to manage the traffic.

Step-by-Step Implementation:

Step 1: Setup ns3 Environment

Make certain ns3 is installed in the system.

Step 2: Include Necessary Modules

Include the necessary ns3 modules in your script:

#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/traffic-control-module.h”

#include “ns3/flow-monitor-module.h”

Step 3: Create the Simulation Script

1. Setup Nodes and Network:

using namespace ns3;

NS_LOG_COMPONENT_DEFINE (“TrafficControlExample”);

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

{

CommandLine cmd;

cmd.Parse (argc, argv);

// Create nodes

NodeContainer nodes;

nodes.Create (4);

// Create point-to-point links

PointToPointHelper pointToPoint;

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

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

NetDeviceContainer devices;

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

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

devices = pointToPoint.Install (nodes.Get (2), nodes.Get (3));

// 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);

// Traffic Control: Set up queue disciplines

TrafficControlHelper tch;

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

tch.Install (devices);

// Set up applications

uint16_t port = 9;  // Discard port (RFC 863)

// Server application on node 3

Address serverAddress (InetSocketAddress (Ipv4Address::GetAny (), port));

PacketSinkHelper packetSinkHelper (“ns3::UdpSocketFactory”, serverAddress);

ApplicationContainer sinkApps = packetSinkHelper.Install (nodes.Get (3));

sinkApps.Start (Seconds (1.0));

sinkApps.Stop (Seconds (20.0));

// Client application on node 0

OnOffHelper onoff (“ns3::UdpSocketFactory”, Address (InetSocketAddress (interfaces.GetAddress (3), port)));

onoff.SetConstantRate (DataRate (“1Mbps”));

ApplicationContainer apps = onoff.Install (nodes.Get (0));

apps.Start (Seconds (2.0));

apps.Stop (Seconds (20.0));

// Flow monitor

FlowMonitorHelper flowmon;

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

Simulator::Stop (Seconds (20.0));

Simulator::Run ();

monitor->SerializeToXmlFile(“flowmon-results.xml”, true, true);

Simulator::Destroy ();

return 0;

}

Step 4: Run the Simulation

Compile and run your simulation script:

sh

./waf configure

./waf build

./waf –run TrafficControlExample

Explanation

• Node Creation: Create nodes representing different devices in the network.
• Point-to-Point Links: Configure point-to-point links between nodes.
• Internet Stack: Install the Internet stack on all nodes.
• IP Configuration: Assign IP addresses to the nodes.
• Traffic Control: Use the TrafficControlHelper to install a queue discipline (e.g., RED) on the devices. The example uses RED (Random Early Detection) to manage queue lengths and drop packets probabilistically.
• Applications: Use OnOffApplication and PacketSink to simulate traffic between nodes.
• Flow Monitor: Use the flow monitor to collect traffic data and save it to an XML file for analysis.

Advanced Traffic Control Techniques

1. Rate Limiting:

Implement rate limiting using token bucket filters (TBF) or hierarchical token bucket (HTB) queues.

TrafficControlHelper tch;

tch.SetRootQueueDisc (“ns3::TbfQueueDisc”, “MaxSize”, StringValue (“100p”));

tch.Install (devices);

1. Traffic Shaping:

Use traffic shaping to control the rate and burst size of traffic flows.

TrafficControlHelper tch;

tch.SetRootQueueDisc (“ns3::FifoQueueDisc”, “MaxSize”, QueueSizeValue (QueueSize (“50p”)));

tch.Install (devices);

1. Quality of Service (QoS):

Implement QoS to prioritize traffic and manage congestion.

TrafficControlHelper tch;

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

tch.Install (devices);

1. Custom Queue Disciplines:

Implement custom queue disciplines for specific traffic control needs.

class MyCustomQueueDisc : public QueueDisc

{

public:

static TypeId GetTypeId (void);

MyCustomQueueDisc ();

protected:

virtual bool DoEnqueue (Ptr<QueueDiscItem> item);

virtual Ptr<QueueDiscItem> DoDequeue (void);

virtual Ptr<const QueueDiscItem> DoPeek (void) const;

};

NS_OBJECT_ENSURE_REGISTERED (MyCustomQueueDisc);

TypeId

MyCustomQueueDisc::GetTypeId (void)

{

static TypeId tid = TypeId (“MyCustomQueueDisc”)

.SetParent<QueueDisc> ()

.AddConstructor<MyCustomQueueDisc> ();

return tid;

}

MyCustomQueueDisc::MyCustomQueueDisc ()

{

}

bool

MyCustomQueueDisc::DoEnqueue (Ptr<QueueDiscItem> item)

{

// Custom enqueue logic

return true;

}

Ptr<QueueDiscItem>

MyCustomQueueDisc::DoDequeue (void)

{

// Custom dequeue logic

return 0;

}

Ptr<const QueueDiscItem>

MyCustomQueueDisc::DoPeek (void) const

{

// Custom peek logic

return 0;

}

// In main function, register and install the custom queue discipline

TrafficControlHelper tch;

tch.SetRootQueueDisc (“MyCustomQueueDisc”);

tch.Install (devices);

Here, we clearly provide how to control the traffics in the generated network and analyse the outcomes using ns3 implementation tool. We will plan to provide the additional details on the network traffic control will perform in other simulation tools.

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