How to Implement next hop protocol in OMNeT++
To implement the next-hop routing protocol in OMNeT++ requires a numerous steps. To forward the packets in the direction of destination node, we can use next-hop routing protocol which defines the next hop (or next immediate node). We have to define the protocol, generate essential modules, and integrating them into the INET framework to implement it.. Here’s a detailed guide to help you through this process.
Step-by-Step implementation:
Step 1: Set Up OMNeT++ and INET Framework
- Install OMNeT++: Make sure to install the latest version of OMNeT++.
- Install INET Framework: Download and install the INET framework from the INET repository.
Step 2: Understand Next-Hop Routing Protocol
To state the next hop for forwarding packet onto their destination, we can implement the A next-hop routing protocol uses routing tables This guide will help you create a basic next-hop routing protocol module.
Step 3: Create the Next-Hop Protocol Module
Define the Module in .ned File
Create a .ned file for the next-hop routing protocol module.
simple NextHopRouting
{
parameters:
@display(“i=block/cogwheel”);
double updateInterval @unit(s) = default(1s);
gates:
input fromNetworkLayer;
output toNetworkLayer;
input fromMacLayer;
output toMacLayer;
}
Implement the Module in C++
Create the corresponding .cc and .h files.
NextHopRouting.h
#ifndef __NEXTHOPROUTING_H_
#define __NEXTHOPROUTING_H_
#include <omnetpp.h>
#include “inet/networklayer/contract/IRoutingTable.h”
#include “inet/common/INETDefs.h”
#include <map>
using namespace omnetpp;
using namespace inet;
class NextHopRouting : public cSimpleModule
{
private:
double updateInterval;
IRoutingTable *routingTable;
cMessage *updateMsg;
std::map<L3Address, L3Address> nextHopTable; // Maps destination to next hop
protected:
virtual void initialize() override;
virtual void handleMessage(cMessage *msg) override;
void sendPeriodicUpdate();
void processUpdate(cMessage *msg);
void updateRoutingTable();
public:
NextHopRouting();
virtual ~NextHopRouting();
};
#endif
NextHopRouting.cc
#include “NextHopRouting.h”
Define_Module(NextHopRouting);
NextHopRouting::NextHopRouting()
{
updateMsg = nullptr;
}
NextHopRouting::~NextHopRouting()
{
cancelAndDelete(updateMsg);
}
void NextHopRouting::initialize()
{
updateInterval = par(“updateInterval”);
routingTable = getModuleFromPar<IRoutingTable>(par(“routingTableModule”), this);
updateMsg = new cMessage(“sendPeriodicUpdate”);
scheduleAt(simTime() + updateInterval, updateMsg);
}
void NextHopRouting::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 (nextHopTable.find(dest) != nextHopTable.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 NextHopRouting::sendPeriodicUpdate()
{
cMessage *update = new cMessage(“Update”);
// Add routing information to the update message
for (const auto &entry : nextHopTable)
{
update->addPar(entry.first.str().c_str()) = entry.second.str().c_str();
}
send(update, “toMacLayer”);
}
void NextHopRouting::processUpdate(cMessage *msg)
{
// Process received update message
for (int i = 0; i < msg->getParList().size(); ++i)
{
const char *key = msg->getParList().get(i).getName();
const char *value = msg->par(key).stringValue();
L3Address dest(key);
L3Address nextHop(value);
nextHopTable[dest] = nextHop;
}
updateRoutingTable();
delete msg;
}
void NextHopRouting::updateRoutingTable()
{
// Update the routing table based on the next-hop information
for (const auto &entry : nextHopTable)
{
L3Address dest = entry.first;
L3Address nextHop = entry.second;
// Add route to the routing table
routingTable->addRoute(new Ipv4Route(dest, nextHop, 1)); // Example route with hop count 1
}
}
Step 4: Integrate with Simulation Model
Assimilate the module into a network simulation model.
Network Configuration .ned File
network NextHopNetwork
{
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 = NextHopNetwork
*.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 = “NextHopRouting”
Step 5: Test and Debug
- Run Simulations: Execute simulations to test the behavior of the NextHopRouting 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, we have provided the step-by-step procedure to execute the next hop protocol and understand how it forward the packets using this protocol and INET framework in the OMNeT++. We are planning to offer another simulation process for further references so stay in touch with us for getting best project topics and simulation support.