How to Implement igp protocol in OMNeT++

To implement an IGP (Interior Gateway Protocol) like OSPF (Open Shortest Path First) or RIP (Routing Information Protocol) in OMNeT++, among the routing of data packets, we have to design the nodes and communication patterns of the network. The step-by-step guide to implementing an IGP protocol in OMNeT++ using the INET framework, focusing on OSPF as an example in the following below:

Step-by-Step Implementation:

Install OMNeT++ and INET Framework

Make sure that you have OMNeT++ and INET framework is installed.

Create a New OMNeT++ Project

Open OMNeT++ IDE: Start the OMNeT++ IDE.
Create a New Project: Go to File -> New -> OMNeT++ Project and name it (for example: IGPSimulation).

Define the Network Topology

State the network topology like hosts and routers that will run the IGP protocol by generating a new NED file.

Example: IGP Network Topology (IGPNetwork.ned)

package igpnetwork;

import inet.node.inet.StandardHost;

import inet.node.inet.Router;

network IGPNetwork

{

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

Configure the simulation’s parameter by making an initialization file of OMNeT++.

Example: Configuration File (omnetpp.ini)

network = igpnetwork.IGPNetwork

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 = “OSPFApp”

Create IP Address Configuration Files

Create XML files to state the IP address configuration for all 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 OSPF Logic

Simulate the OSPF protocol by executing an application which handles the exchange of OSPF messages and updates the routing table.

Example: OSPF Router Application (Pseudo-Code)

#include <omnetpp.h>

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

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

#include <inet/networklayer/routing/Ipv4RoutingTable.h>

#include <inet/common/ModuleAccess.h>

#include <map>

using namespace omnetpp;

using namespace inet;

class OSPFApp : public ApplicationBase

{

protected:

std::map<Ipv4Address, std::pair<Ipv4Address, int>> ospfRoutingTable; // Destination, (Next Hop, Metric)

simtime_t helloInterval;

cMessage *helloTimer;

virtual void initialize(int stage) override;

virtual void handleMessageWhenUp(cMessage *msg) override;

void handlePacket(cMessage *msg);

void sendHelloPackets();

void processHelloPacket(cMessage *msg);

void updateRoutingTable();

};

Define_Module(OSPFApp);

void OSPFApp::initialize(int stage) {

ApplicationBase::initialize(stage);

if (stage == INITSTAGE_APPLICATION_LAYER) {

helloInterval = par(“helloInterval”);

helloTimer = new cMessage(“helloTimer”);

scheduleAt(simTime() + helloInterval, helloTimer);

updateRoutingTable();

}

void OSPFApp::handleMessageWhenUp(cMessage *msg) {

if (msg == helloTimer) {

sendHelloPackets();

scheduleAt(simTime() + helloInterval, helloTimer);

} else if (msg->isPacket()) {

handlePacket(msg);

} else {

ApplicationBase::handleMessageWhenUp(msg);

}

void OSPFApp::handlePacket(cMessage *msg) {

if (strcmp(msg->getName(), “HelloPacket”) == 0) {

processHelloPacket(msg);

} else {

// Handle other packet types

}

void OSPFApp::sendHelloPackets() {

// Create and send Hello packets to neighbors

for (auto &entry : ospfRoutingTable) {

cMessage *helloMsg = new cMessage(“HelloPacket”);

helloMsg->addPar(“srcAddr”) = Ipv4Address(“192.168.1.254”).str().c_str();

send(helloMsg, “ifOut”);

}

void OSPFApp::processHelloPacket(cMessage *msg) {

// Process incoming Hello packets

Ipv4Address srcAddr = Ipv4Address(msg->par(“srcAddr”).stringValue());

// Update routing table or neighbor table based on Hello packet information

delete msg;

}

void OSPFApp::updateRoutingTable() {

// Example static routing table

ospfRoutingTable[Ipv4Address(“192.168.1.1”)] = std::make_pair(Ipv4Address(“10.0.0.2”), 1);

ospfRoutingTable[Ipv4Address(“192.168.1.2”)] = std::make_pair(Ipv4Address(“10.0.0.1”), 1);

}

Configure and Initialize the Simulation

To use the custom OSPF protocol, we have to make certain that the routes are configured.

Example: Configuration File (omnetpp.ini)

network = igpnetwork.IGPNetwork

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 = “OSPFApp”

*.router*.app[0].helloInterval = 10s

Run the Simulation

Build the Project: Right-click on the project and select Build Project.
Run the Simulation: In OMNeT++ IDE, click on the green play button to start the simulation.

As we discussed earlier in this demonstration, we have shown you the entire details on how to implement the igp protocols in OMNeT++. If you need any additional details of igp protocols or how they work in another simulation process, we can guide you.

We guide you in implementing IGP (Interior Gateway Protocol) such as OSPF or RIP in OMNeT++ will be clear to you. Our developers are dedicated to enhancing simulation and project performance. We focus on all nodes and communication patterns within the network that pertain to your projects.