How to Implement Network Routing in OMNeT++

To implement the network routing in OMNeT++ consist of set up a replication situation, describing network and node copies, and executing routing protocols. Now the below steps are using by INET framework to get started:

Step-by-Step Implementations:

Step 1: Install OMNeT++ and INET Framework

1. Download OMNeT++:
   • Go to theOMNeT++   download the newest version.
2. Install OMNeT++:
   • For the operating system we move to the installation instructions contribute on the website.
3. Download and Install INET Framework:
   • The INET framework provides models for internet protocols and is often used with OMNeT++.
   • From the INET website we download it.

Step 2: Set Up Your Project

1. Create a New OMNeT++ Project:
   • Open the OMNeT++ IDE.
   • Go to File -> New -> OMNeT++ Project.
   • Choose the options and put a project name.
2. Set Up Directory Structure:
   • Make a certain the project have the required folders, like a src for source files and for NED files to simulate and formations.
3. Add INET to Your Project:
   • Click on the project in the Project Explorer.
   • Handpicked Properties -> Project References.
   • Form the box for INET.

Step 3: Define Network Models Using NED

1. Create NED Files:
   • In the src directory, to generate a new NED file like NetworkRouting.ned.
   • Express the network topology in the NED file. The following is a simple example:

package networkrouting;

import inet.node.inet.StandardHost;

import inet.node.inet.Router;

import inet.networklayer.configurator.ipv4.Ipv4NetworkConfigurator;

import inet.networklayer.autorouting.ipv4.Ipv4FlatNetworkConfigurator;

network NetworkRouting

{

parameters:

int numHosts = default(4);

int numRouters = default(2);

submodules:

configurator: Ipv4FlatNetworkConfigurator {

@display(“p=100,100”);

}

router[numRouters]: Router {

@display(“p=200,100+100*i”);

}

host[numHosts]: StandardHost {

@display(“p=300,100+100*i”);

}

connections allowunconnected:

for i=0..numRouters-1 {

for j=i+1..numRouters-1 {

router[i].pppg++ <–> Ethernet100M <–> router[j].pppg++;

}

for k=0..numHosts-1 {

host[k].pppg++ <–> Ethernet100M <–> router[i % numRouters].pppg++;

}

}

}

Step 4: Implement Routing Logic

1. Use Built-In Routing Protocols:
   • INET affords some built-in routing protocols such as OSPF, RIP, and AODV.
   • In the simulation we use this openly.
2. Example: Configuring OSPF:
   • Construct a modest OSPF configuration in the NED file:

import inet.networklayer.ospfv2.OspfRouter;

network NetworkRoutingWithOSPF

{

parameters:

int numHosts = default(4);

int numRouters = default(2);

submodules:

configurator: Ipv4FlatNetworkConfigurator {

@display(“p=100,100”);

}

router[numRouters]: OspfRouter {

@display(“p=200,100+100*i”);

}

host[numHosts]: StandardHost {

@display(“p=300,100+100*i”);

}

connections allowunconnected:

for i=0..numRouters-1 {

for j=i+1..numRouters-1 {

router[i].pppg++ <–> Ethernet100M <–> router[j].pppg++;

}

for k=0..numHosts-1 {

host[k].pppg++ <–> Ethernet100M <–> router[i % numRouters].pppg++;

}

}

}

1. Configure OSPF in omnetpp.ini:

[General]

network = NetworkRoutingWithOSPF

sim-time-limit = 100s

**.router*.routingTable.ospfConfig = xmldoc(“osfpConfig.xml”)

1. Create osfpConfig.xml:

• To describe the OSPF configuration in an XML file. For example:

<config>

<interface ifname=”ppp0″ area=”0.0.0.0″/>

<interface ifname=”ppp1″ area=”0.0.0.0″/>

</config>

Step 5: Implement Custom Routing Protocols (Optional)

1. Create C++ Modules:
   • In the src directory, to build a new C++ class like CustomRouting.cc.
   • Embrace necessary OMNeT++ headers and state the custom routing logic:

#include <omnetpp.h>

#include “inet/networklayer/ipv4/Ipv4RoutingTable.h”

#include “inet/networklayer/contract/ipv4/Ipv4Address.h”

#include “inet/networklayer/contract/IRoutingTable.h”

using namespace omnetpp;

using namespace inet;

class CustomRouting : public cSimpleModule

{

protected:

Ipv4RoutingTable *routingTable;

virtual void initialize() override;

virtual void handleMessage(cMessage *msg) override;

void configureRouting();

};

Define_Module(CustomRouting);

void CustomRouting::initialize()

{

routingTable = check_and_cast<Ipv4RoutingTable *>(getModuleByPath(“^.ipv4.routingTable”));

configureRouting();

}

void CustomRouting::handleMessage(cMessage *msg)

{

// Handle messages if needed

}

void CustomRouting::configureRouting()

{

// Add custom routing logic

Ipv4Route *route = new Ipv4Route();

route->setDestination(Ipv4Address(“10.0.0.1”));

route->setNetmask(Ipv4Address(“255.255.255.0”));

route->setGateway(Ipv4Address(“10.0.0.2”));

route->setInterface(routingTable->getInterfaceByName(“eth0”));

route->setSourceType(IRoute::MANUAL);

routingTable->addRoute(route);

}

1. Modify NED to Use Custom Modules:
   • Apprise your NED file to use the custom routing module:

network NetworkRoutingWithCustom

{

parameters:

int numHosts = default(4);

int numRouters = default(2);

submodules:

configurator: Ipv4FlatNetworkConfigurator {

@display(“p=100,100”);

}

router[numRouters]: Router {

@display(“p=200,100+100*i”);

@children:

customRouting: CustomRouting;

}

host[numHosts]: StandardHost {

@display(“p=300,100+100*i”);

}

connections allowunconnected:

for i=0..numRouters-1 {

for j=i+1..numRouters-1 {

router[i].pppg++ <–> Ethernet100M <–> router[j].pppg++;

}

for k=0..numHosts-1 {

host[k].pppg++ <–> Ethernet100M <–> router[i % numRouters].pppg++;

}

}

}

Step 6: Configure Simulation Parameters

1. Create omnetpp.ini:
   • In the simulations manual, produce an omnetpp.ini file.
   • State simulation parameters, like the duration and network parameters:

[General]

network = NetworkRoutingWithOSPF

sim-time-limit = 100s

# Configure OSPF

**.router*.routingTable.ospfConfig = xmldoc(“ospfConfig.xml”)

Step 7: Build and Run the Simulation

1. Build the Project:
   • To right-click on the project and choose Build Project in the OMNeT++ IDE.
2. Run the Simulation:
   • Go to Run -> Run Configurations.
   • Setting up a new run formation for the project and run the simulation.

Step 8: Analyze Results

1. View Simulation Results:
   • By using the OMNeT++’s tools to evaluate the results then the simulation completed.
   • Exposed the ANF which is Analysis Framework to envision and understand the informations.

In the above discussion, we are see about the Network Routing and then how we implement custom routing protocols and enactment file by using Network Routing which is executed using OMNeT++ tool. We are willing to offer more material about the Network Routing in OMNeT++.

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