How to implement routing protocols in OMNeT++

To implement routing protocols in OMNeT++ has includes to describe the features of the network loads and the communication patterns among them to handle the routing of data packets. The given below are the procedures on implementing routing protocols in OMNeT++ using the INET framework:

Step-by-Step Implementation

Install OMNeT++ and INET Framework

Make certain we have OMNeT++ and the INET Framework installed.

Create a New OMNeT++ Project

Open OMNeT++ IDE: Start the OMNeT++ IDE.
Create a New Project: Go to File -> New -> OMNeT++ Project. Name your project (e.g., RoutingProtocolSimulation).

Define the Network Topology

Generate a new NED file to describe network topology has contains hosts and routers.

Example: Network Topology (RoutingNetwork.ned)

package routingnetwork;

import inet.node.inet.StandardHost;

import inet.node.inet.Router;

network RoutingNetwork

{

parameters:

@display(“bgb=800,400”);

submodules:

host1: StandardHost {

@display(“p=100,200”);

}

host2: StandardHost {

@display(“p=300,200”);

}

router1: Router {

@display(“p=200,100”);

}

router2: Router {

@display(“p=200,300”);

}

connections allowunconnected:

host1.ethg++ <–> Eth10M <–> router1.ethg++;

host2.ethg++ <–> Eth10M <–> router2.ethg++;

router1.ethg++ <–> Eth10M <–> router2.ethg++;

}

Configure the Simulation

Generate an OMNeT++ initialization file to configure the parameters of the simulation.

Example: Configuration File (omnetpp.ini)

network = routingnetwork.RoutingNetwork

sim-time-limit = 200s

# Visualization

*.visualizer.canvasVisualizer.displayBackground = true

*.visualizer.canvasVisualizer.displayGrid = true

# Host Configuration

*.host*.numApps = 1

*.host*.app[0].typename = “UdpBasicApp”

*.host*.app[0].destAddresses = “host2”

*.host*.app[0].destPort = 5000

*.host*.app[0].messageLength = 1024B

*.host*.app[0].sendInterval = 1s

# Routing Configuration

*.router*.routingProtocol = “RoutingProtocolApp”

Create IP Address Configuration Files

Generate XML files to define the IP address configuration for each node.

Example: IP Configuration File for host1 (host1.xml)

</interface>

</config>

Example: IP Configuration File for host2 (host2.xml)

</interface>

</config>

Example: IP Configuration File for router1 (router1.xml)

</interface>

</interface>

</config>

Example: IP Configuration File for router2 (router2.xml)

</interface>

</interface>

</config>

Implement Routing Protocol Logic

To mimic routing protocols to execute an application that describes the routing behaviour for routers.

Example: Routing Protocol Application (Pseudo-Code)

#include <omnetpp.h>

#include <inet/applications/base/ApplicationBase.h>

#include <inet/networklayer/ipv4/Ipv4Header.h>

#include <inet/networklayer/contract/ipv4/Ipv4Address.h>

#include <map>

using namespace omnetpp;

using namespace inet;

class RoutingProtocolApp : public ApplicationBase

{

protected:

std::map<Ipv4Address, Ipv4Address> routingTable;

virtual void initialize(int stage) override;

virtual void handleMessageWhenUp(cMessage *msg) override;

void handlePacket(cMessage *msg);

void updateRoutingTable();

};

Define_Module(RoutingProtocolApp);

void RoutingProtocolApp::initialize(int stage) {

ApplicationBase::initialize(stage);

if (stage == INITSTAGE_APPLICATION_LAYER) {

updateRoutingTable();

}

void RoutingProtocolApp::handleMessageWhenUp(cMessage *msg) {

if (msg->isPacket()) {

handlePacket(msg);

} else {

ApplicationBase::handleMessageWhenUp(msg);

}

void RoutingProtocolApp::handlePacket(cMessage *msg) {

Ipv4Header *ipv4Header = check_and_cast<Ipv4Header *>(msg->removeControlInfo());

Ipv4Address destAddr = ipv4Header->getDestAddress();

auto it = routingTable.find(destAddr);

if (it != routingTable.end()) {

// Forward the packet to the next hop

Ipv4Address nextHop = it->second;

send(msg, “ifOut”, nextHop.getInterfaceId());

} else {

// Drop the packet if no route is found

delete msg;

}

void RoutingProtocolApp::updateRoutingTable() {

// Example static routing table

routingTable[Ipv4Address(“192.168.1.1”)] = Ipv4Address(“10.0.0.2”);

routingTable[Ipv4Address(“192.168.1.2”)] = Ipv4Address(“10.0.0.1”);

}

Configure and Initialize the Simulation

Make sure the routers are configured to use the custom routing protocol.

Example: Configuration File (omnetpp.ini)

network = routingnetwork.RoutingNetwork

sim-time-limit = 200s

# Visualization

*.visualizer.canvasVisualizer.displayBackground = true

*.visualizer.canvasVisualizer.displayGrid = true

# Host Configuration

*.host*.numApps = 1

*.host*.app[0].typename = “UdpBasicApp”

*.host*.app[0].destAddresses = “host2”

*.host*.app[0].destPort = 5000

*.host*.app[0].messageLength = 1024B

*.host*.app[0].sendInterval = 1s

# Router Configuration

*.router*.numApps = 1

*.router*.app[0].typename = “RoutingProtocolApp”

Run the Simulation

Build the Project: Right-click on project and choose Build Project.
Run the Simulation: Click on the green play button in the OMNeT++ IDE to start the simulation.

We finally figured out how to use routing protocols in OMNeT++. This helps us manage the routing of data packets for our projects. If you need more help with simulations, check out omnet-manual.com.