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How to implement unicast routing in OMNeT++

To implement the unicast routing in OMNeT++ has needs to generate the network where each node or router regulates the best path to a particular endpoint and forwards packets along that path and to know that the Unicast routing is the most mutual form of routing in IP networks, where data is sent from a single source to a single destination. The given below is the procedures on how to implement the simple unicast routing protocol in OMNeT++ using the INET framework.

Step-by-Step Implementation:

Step 1: Set Up OMNeT++ and INET Framework

  1. Install OMNeT++:
    • Make sure OMNeT++ is installed on system. We need to  download it from the  OMNeT++
  2. Install the INET Framework:
    • Download and install the INET Framework, which offers numerous networking protocols and models. INET can be downloaded from the INET GitHub repository.

Step 2: Create a New OMNeT++ Project

  1. Create the Project:
    • Open OMNeT++ and generate a new OMNeT++ project through File > New > OMNeT++ Project.
    • Name project like UnicastRoutingSimulation and set up the project directory.
  2. Set Up Project Dependencies:
    • Make certain project references the INET Framework by right-clicking on project in the Project Explorer, navigating to Properties > Project References, and checking the INET project.

Step 3: Define the Network Topology

  1. Create a NED File:
    • Describe the network topology using the NED language. This topology will contains routers and hosts that will use the unicast routing protocol.

Example:

network UnicastRoutingNetwork

{

submodules:

router1: Router;

router2: Router;

router3: Router;

router4: Router;

host1: StandardHost;

host2: StandardHost;

connections allowunconnected:

router1.ethg++ <–> Eth10Mbps <–> router2.ethg++;

router2.ethg++ <–> Eth10Mbps <–> router3.ethg++;

router3.ethg++ <–> Eth10Mbps <–> router4.ethg++;

router1.ethg++ <–> Eth10Mbps <–> host1.ethg++;

router4.ethg++ <–> Eth10Mbps <–> host2.ethg++;

}

  1. Configure Network Parameters:
    • To set up essential link parameters like bandwidth, delay, and packet loss to mimic a realistic network environment.

Step 4: Implement the Unicast Routing Protocol

  1. Define the Unicast Routing Module:
    • Generate a new module in NED for the unicast routing protocol. This module will manage the routing decisions based on the destination address of each packet.

Example (in NED):

simple UnicastRouting

{

parameters:

@display(“i=block/network2”);

gates:

inout lowerLayerIn[];

inout lowerLayerOut[];

}

  1. Implement Unicast Routing Logic in C++:
    • To execute the routing logic in C++ that controls the best path for each packet based on its destination address.

Example (C++ implementation):

#include <map>

#include “inet/common/INETDefs.h”

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

#include “inet/networklayer/ipv4/IPv4RoutingTable.h”

class UnicastRouting : public cSimpleModule

{

private:

IRoutingTable *inetRoutingTable;

protected:

virtual void initialize() override;

virtual void handleMessage(cMessage *msg) override;

void setupRoutingTable();

};

Define_Module(UnicastRouting);

void UnicastRouting::initialize() {

inetRoutingTable = getModuleFromPar<IRoutingTable>(par(“routingTableModule”), this);

// Initialize the routing table with static routes

setupRoutingTable();

}

 

void UnicastRouting::handleMessage(cMessage *msg) {

cPacket *packet = check_and_cast<cPacket *>(msg);

Ipv4Address destAddr = packet->getContextPointer();  // Assuming the packet contains the destination address in its context

const IRoute *route = inetRoutingTable->findBestMatchingRoute(destAddr);

if (route) {

EV << “Forwarding packet to ” << destAddr << ” via ” << route->getGateway() << endl;

send(packet, “lowerLayerOut”, route->getInterface()->getNetworkLayerGateIndex());

} else {

EV << “No route found for ” << destAddr << “. Dropping packet.” << endl;

delete packet;

}

}

void UnicastRouting::setupRoutingTable() {

// Example: Setting up static routing table entries

Ipv4Route *route1 = new Ipv4Route();

route1->setDestination(Ipv4Address(“10.0.0.2”));

route1->setNetmask(Ipv4Address::ALLONES_ADDRESS);

route1->setGateway(Ipv4Address(“10.0.0.1”));

route1->setInterface(inetRoutingTable->getInterfaceByName(“eth0”));

inetRoutingTable->addRoute(route1);

Ipv4Route *route2 = new Ipv4Route();

route2->setDestination(Ipv4Address(“10.0.0.3”));

route2->setNetmask(Ipv4Address::ALLONES_ADDRESS);

route2->setGateway(Ipv4Address(“10.0.0.2”));

route2->setInterface(inetRoutingTable->getInterfaceByName(“eth1”));

inetRoutingTable->addRoute(route2);

}

    • Routing Table: The routing table contains static routes that map destination addresses to next hops.
    • Routing Logic: The module verify the destination address of each packet and forwards it based on the routing table. If no route is found, the packet is dropped.

Step 5: Set Up the Simulation

  1. Configure the Simulation in omnetpp.ini:
    • Set up the simulation parameters, like simulation time, network settings, and traffic patterns.

Example:

network = UnicastRoutingNetwork

sim-time-limit = 100s

**.scalar-recording = true

**.vector-recording = true

# Application traffic configuration

*.host1.numApps = 1

*.host1.app[0].typename = “UdpBasicApp”

*.host1.app[0].destAddress = “host2”

*.host1.app[0].destPort = 5000

*.host1.app[0].messageLength = 1024B

*.host1.app[0].sendInterval = uniform(1s, 2s)

  1. Traffic Configuration:
    • Set up application-level traffic among hosts to create network activity, causing the unicast routing protocol.

Step 6: Run the Simulation

  1. Compile the Project:
    • Guarantee everything is correctly applied and compiled.
  2. Run Simulations:
    • Implement the simulations using OMNeT++’s IDE or command line. Monitor how the unicast routing protocol performs under various conditions.

Step 7: Analyze the Results

  1. Monitor Routing Behavior:
    • To assess how the unicast routing protocol manages routing, specifically how it forwards packets based on destination addresses.
  2. Evaluate Performance:
    • Evaluate key performance metrics like packet delivery ratio, end-to-end delay, and routing overhead.
    • Scalars and Vectors: Use OMNeT++ tools to record and evaluate scalar and vector data, like the number of packets sent, received, and dropped, as well as the time taken to deliver packets.
  3. Check for Issues:
    • Look for issues such as routing loops, packet loss, or excessive delay that may indicate problems with the unicast routing logic.

Step 8: Refine and Optimize the Protocol

  1. Address Any Issues:
    • Improve the routing logic based on the simulation results to enhance performance and address any problems.
  2. Optimize for Performance:
    • Fine-tune parameters such as routing table update intervals, packet forwarding rules, or link cost calculations to optimize network efficiency.
  3. Re-Test:
    • Run the simulation again with the optimized protocol to verify improvements.

In the end, we had explored the basic implementation process on how to execute the unicast routing that handles the information from one source to destination. If you need additional implementation regarding the unicast routing we will provide it too.

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