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How to Implement RIP protocol in OMNeT++

To implement the Routing Information Protocol (RIP) in OMNeT++ has encompasses to design a emulation that models features of RIP has contain to interchanging the routing updates and handles the routing table. The given below is the procedure on how to implement the RIP protocol in OMNeT++ using the INET framework:

Step-by-Step Implementation

  1. Install OMNeT++ and INET Framework

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

  1. Create a New OMNeT++ Project
  1. Open OMNeT++ IDE: Start the OMNeT++ IDE.
  2. Create a New Project: Go to File -> New -> OMNeT++ Project. Name your project (e.g., RIPSimulation).
  1. Define the Network Topology

Generate a new NED file to describe network topology has contains hosts and routers that will execute the RIP protocol.

Example: RIP Network Topology (RIPNetwork.ned)

package ripnetwork;

import inet.node.inet.StandardHost;

import inet.node.inet.Router;

network RIPNetwork

{

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++;

}

  1. Configure the Simulation

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

Example: Configuration File (omnetpp.ini)

network = ripnetwork.RIPNetwork

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 = “RipRouterApp”

  1. 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)

<config>

<interface>

<name>eth0</name>

<address>192.168.1.1</address>

<netmask>255.255.255.0</netmask>

</interface>

</config>

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

<config>

<interface>

<name>eth0</name>

<address>192.168.1.2</address>

<netmask>255.255.255.0</netmask>

</interface>

</config>

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

<config>

<interface>

<name>eth0</name>

<address>192.168.1.254</address>

<netmask>255.255.255.0</netmask>

</interface>

<interface>

<name>eth1</name>

<address>10.0.0.1</address>

<netmask>255.255.255.0</netmask>

</interface>

</config>

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

<config>

<interface>

<name>eth0</name>

<address>192.168.2.254</address>

<netmask>255.255.255.0</netmask>

</interface>

<interface>

<name>eth1</name>

<address>10.0.0.2</address>

<netmask>255.255.255.0</netmask>

</interface>

</config>

  1. Implement RIP Logic

To emulate the RIP protocol to execute an application that manages the periodic exchange of routing information and updates the routing table.

Example: RIP Router 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 <inet/networklayer/routing/RoutingTable.h>

#include <inet/networklayer/routing/ipv4/Ipv4RoutingTable.h>

#include <map>

using namespace omnetpp;

using namespace inet;

class RipRouterApp : public ApplicationBase

{

protected:

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

simtime_t updateInterval;

cMessage *updateTimer;

virtual void initialize(int stage) override;

virtual void handleMessageWhenUp(cMessage *msg) override;

void handlePacket(cMessage *msg);

void updateRoutingTable();

void sendRoutingUpdates();

void processRoutingUpdate(cMessage *msg);

void addOrUpdateRoute(const Ipv4Address &dest, const Ipv4Address &nextHop, int metric);

};

Define_Module(RipRouterApp);

void RipRouterApp::initialize(int stage) {

ApplicationBase::initialize(stage);

if (stage == INITSTAGE_APPLICATION_LAYER) {

updateInterval = par(“updateInterval”);

updateTimer = new cMessage(“updateTimer”);

scheduleAt(simTime() + updateInterval, updateTimer);

updateRoutingTable();

}

}

void RipRouterApp::handleMessageWhenUp(cMessage *msg) {

if (msg == updateTimer) {

sendRoutingUpdates();

scheduleAt(simTime() + updateInterval, updateTimer);

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

handlePacket(msg);

} else {

ApplicationBase::handleMessageWhenUp(msg);

}

}

void RipRouterApp::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.first;

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

} else {

// Drop the packet if no route is found

delete msg;

}

}

void RipRouterApp::updateRoutingTable() {

// Example static routing table

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

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

}

void RipRouterApp::sendRoutingUpdates() {

// Create and send routing update packets to neighbors

for (auto &entry : routingTable) {

cMessage *updateMsg = new cMessage(“RoutingUpdate”);

updateMsg->addPar(“destAddr”) = entry.first.str().c_str();

updateMsg->addPar(“nextHop”) = entry.second.first.str().c_str();

updateMsg->addPar(“metric”) = entry.second.second;

send(updateMsg, “ifOut”);

}

}

void RipRouterApp::processRoutingUpdate(cMessage *msg) {

// Process incoming routing update messages

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

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

int metric = msg->par(“metric”);

addOrUpdateRoute(destAddr, nextHop, metric);

delete msg;

}

void RipRouterApp::addOrUpdateRoute(const Ipv4Address &dest, const Ipv4Address &nextHop, int metric) {

auto it = routingTable.find(dest);

if (it == routingTable.end() || it->second.second > metric) {

routingTable[dest] = std::make_pair(nextHop, metric);

}

}

  1. Configure and Initialize the Simulation

Guarantee the routers are configured to use the custom RIP protocol.

Example: Configuration File (omnetpp.ini)

network = ripnetwork.RIPNetwork

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 = “RipRouterApp”

*.router*.app[0].updateInterval = 30s

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

We have successfully examined the implementation of the RIP protocol in OMNeT++, focusing on managing routing updates and maintaining the routing table for execution. Please reach out to us for any additional simulation requirements.

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