How to Implement layer 3 routed protocol in OMNeT++
To implement the Layer 3 routing protocol in OMNeT++, we need a network that should replicate the actions of routing protocol, combine them with INET framework and examine the simulation and validate the implementation. In the below, we offered a step-by-step approach to implement it in OMNeT++:
Step-by-Step implementation:
Step 1: Set Up OMNeT++ and INET Framework
- Install OMNeT++: Make sure that you have installed the latest version of OMNeT++.
- Install INET Framework: Download and install the INET framework from the INET repository.
Step 2: Understand the Layer 3 Routing Protocol
Layer 3 routing protocols manage the packet forwarding process by defining the optimal path for data packets to travel through the network. It is focused on a plain distance-vector routing protocol related to RIP (Routing Information Protocol).
Step 3: Create the Layer 3 Routing Protocol Module
Define the Module in .ned File
Create a .ned file for the Layer 3 routing protocol module.
simple Layer3Routing
{
parameters:
@display(“i=block/cogwheel”);
double updateInterval @unit(s) = default(30s); // Interval for sending routing updates
gates:
input fromNetworkLayer;
output toNetworkLayer;
input fromMacLayer;
output toMacLayer;
}
Implement the Module in C++
Generate the corresponding .cc and .h files.
Layer3Routing.h
#ifndef __LAYER3ROUTING_H_
#define __LAYER3ROUTING_H_
#include <omnetpp.h>
#include “inet/networklayer/contract/IRoutingTable.h”
#include “inet/common/INETDefs.h”
#include <map>
using namespace omnetpp;
using namespace inet;
class Layer3Routing : public cSimpleModule
{
private:
double updateInterval;
IRoutingTable *routingTable;
cMessage *updateMsg;
std::map<L3Address, std::pair<L3Address, int>> routingTableMap; // Maps destination to next hop and hop count
protected:
virtual void initialize() override;
virtual void handleMessage(cMessage *msg) override;
void sendPeriodicUpdate();
void processUpdate(cMessage *msg);
void updateRoutingTable();
public:
Layer3Routing();
virtual ~Layer3Routing();
};
#endif
Layer3Routing.cc
#include “Layer3Routing.h”
Define_Module(Layer3Routing);
Layer3Routing::Layer3Routing()
{
updateMsg = nullptr;
}
Layer3Routing::~Layer3Routing()
{
cancelAndDelete(updateMsg);
}
void Layer3Routing::initialize()
{
updateInterval = par(“updateInterval”);
routingTable = getModuleFromPar<IRoutingTable>(par(“routingTableModule”), this);
updateMsg = new cMessage(“sendPeriodicUpdate”);
scheduleAt(simTime() + updateInterval, updateMsg);
}
void Layer3Routing::handleMessage(cMessage *msg)
{
if (msg == updateMsg)
{
sendPeriodicUpdate();
scheduleAt(simTime() + updateInterval, updateMsg);
}
else if (strcmp(msg->getName(), “Update”) == 0)
{
processUpdate(msg);
}
else if (dynamic_cast<cPacket *>(msg))
{
// Handle incoming data packets
L3Address dest = L3AddressResolver().resolve(msg->par(“destAddr”).stringValue());
if (routingTableMap.find(dest) != routingTableMap.end())
{
// Forward the packet to the next hop
send(msg, “toMacLayer”);
}
else
{
// Drop the packet if no route found
delete msg;
}
}
else
{
// Handle other messages
}
}
void Layer3Routing::sendPeriodicUpdate()
{
cMessage *update = new cMessage(“Update”);
// Add routing information to the update message
for (const auto &entry : routingTableMap)
{
update->addPar(entry.first.str().c_str()) = entry.second.first.str().c_str(); // next hop
update->addPar(entry.first.str().c_str()) = entry.second.second; // hop count
}
send(update, “toMacLayer”);
}
void Layer3Routing::processUpdate(cMessage *msg)
{
// Process received update message
for (int i = 0; i < msg->getParList().size(); i += 2)
{
const char *key = msg->getParList().get(i).getName();
const char *value = msg->par(key).stringValue();
int hopCount = msg->par(key).intValue();
L3Address dest(key);
L3Address nextHop(value);
routingTableMap[dest] = std::make_pair(nextHop, hopCount);
}
updateRoutingTable();
delete msg;
}
void Layer3Routing::updateRoutingTable()
{
// Update the routing table based on the next-hop information
for (const auto &entry : routingTableMap)
{
L3Address dest = entry.first;
L3Address nextHop = entry.second.first;
int hopCount = entry.second.second;
// Update or add route to the routing table
Ipv4Route *route = new Ipv4Route();
route->setDestination(dest.toIpv4());
route->setNextHop(nextHop.toIpv4());
route->setMetric(hopCount);
route->setInterface(routingTable->getInterfaceByAddress(nextHop));
routingTable->addRoute(route);
}
}
Step 4: Integrate with Simulation Model
In network simulation model, we have incorporate the Layer3Routing module.
Network Configuration .ned File
network Layer3Network
{
submodules:
node1: StandardHost {
parameters:
@display(“p=100,100”);
}
node2: StandardHost {
parameters:
@display(“p=300,100”);
}
// Add more nodes as needed
connections:
node1.pppg++ <–> { @display(“m=100,100”); } <–> node2.pppg++;
}
omnetpp.ini Configuration
network = Layer3Network
*.node*.pppg[*].queue.typename = “DropTailQueue”
*.node*.ipv4.routingTable = “inet.networklayer.routing.manet.Router”
*.node*.networkLayer.networkProtocol.typename = “IPv4NetworkLayer”
*.node*.transportLayer.tcp.typename = “Tcp”
*.node*.transportLayer.udp.typename = “Udp”
*.node*.application[*].typename = “UdpBasicApp”
*.node*.application[*].destAddresses = “node1” // Set destination as needed
*.node*.application[*].destPort = 2000
*.node*.application[*].startTime = uniform(0s, 10s)
*.node*.application[*].sendInterval = uniform(1s, 2s)
*.node*.application[*].packetLength = 512B
*.node*.app[0].typename = “Layer3Routing”
Step 5: Test and Debug
- Run Simulations: Execute simulations to examine their actions of Layer3Routing module under different network conditions.
- Analyze Results: Verify the correctness and performance of the implementation.
- Debugging: Use OMNeT++’s debugging tools to troubleshoot any issues.
Finally, this guide will focus on creating a simplified version of a generic Layer 3 routing protocol and implementing them using INET framework in the OMNeT++ framework. You can inquire about any added information of layer 3 protocol, we will send them. We work on simulation and validate the implementation of layer 3 routed protocol in OMNeT++ program for your project .