Steps To Implement Network Routing in NS3

To implement network routing in ns-3, first we need to set up a network topology which contains multiple nodes and configuring routing protocols to manage the paths that data packets travel through the network. The following step-by-step guide helps to create a simple network topology with dynamic routing using the OLSR (Optimized Link State Routing) protocol.

Here is the Step-by-Step Guide to Implement Network Routing in ns-3 :

Install ns-3 :

Make sure that ns-3 is installed. If not, follow the installation illustrations to install ns-3.

Create a simulation script :

Create a new script file in ns-3, e.g., network-routing-simulation.cc.

Include necessary headers :

#include “ns3/core-module.h”

#include “ns3/network-module.h”

#include “ns3/internet-module.h”

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

#include “ns3/mobility-module.h”

#include “ns3/applications-module.h”

#include “ns3/olsr-helper.h”

Define the Main Function:

using namespace ns3;

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

{

CommandLine cmd;

cmd.Parse (argc, argv);

Set Up the Network Topology:

To set up the network topology, create nodes and configure network settings

NodeContainer nodes;

nodes.Create (6); // Create 6 nodes

PointToPointHelper pointToPoint;

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

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

NetDeviceContainer devices;

Ipv4AddressHelper address;

// Create point-to-point links between nodes

for (uint32_t i = 0; i < nodes.GetN() – 1; ++i)

{

NetDeviceContainer link = pointToPoint.Install (nodes.Get(i), nodes.Get(i+1));

devices.Add (link);

std::ostringstream subnet;

subnet << “10.1.” << i+1 << “.0”;

address.SetBase (subnet.str().c_str(), “255.255.255.0”);

address.Assign (link);

}

Install Internet Stack and Routing Protocol:

Install the Internet stack on all nodes which was created previously and enable OLSR routing protocol

InternetStackHelper stack;

OlsrHelper olsr;

stack.SetRoutingHelper (olsr);

stack.Install (nodes);

Ipv4AddressHelper ipv4;

ipv4.SetBase (“10.1.0.0”, “255.255.255.0”);

Ipv4InterfaceContainer interfaces = ipv4.Assign (devices);

Configure Mobility (Optional):

Set up mobility models for the nodes (optional).

MobilityHelper mobility;

mobility.SetMobilityModel (“ns3::ConstantPositionMobilityModel”);

mobility.Install (nodes);

Install Applications:

Set up a UDP echo server on the one node and a UDP echo client on another node

UdpEchoServerHelper echoServer (9);

ApplicationContainer serverApps = echoServer.Install (nodes.Get (0));

serverApps.Start (Seconds (1.0));

serverApps.Stop (Seconds (10.0));

UdpEchoClientHelper echoClient (interfaces.GetAddress (0), 9);

echoClient.SetAttribute (“MaxPackets”, UintegerValue (1));

echoClient.SetAttribute (“Interval”, TimeValue (Seconds (1.0)));

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

ApplicationContainer clientApps = echoClient.Install (nodes.Get (5));

clientApps.Start (Seconds (2.0));

clientApps.Stop (Seconds (10.0));

Run the Simulation:

Define the simulation stop time and start the simulator:

Simulator::Stop (Seconds (10.0));

Simulator::Run ();

Simulator::Destroy ();

return 0;

Example Complete Script (network-routing-simulation.cc):