How to Implement a classless protocol in OMNeT++
To implement a classless routing protocol in OMNeT++ requires a few steps. Border Gateway Protocol (BGP) is the one that uses classless routing protocol which helps Classless Inter-Domain Routing (CIDR). We provided the step-by-step implementation of classless protocol in OMNeT++:
Step-by-Step Implementation:
Step 1: Set Up OMNeT++ and INET Framework
- Install OMNeT++: Make certain that you have OMNeT++ installed.
- Install INET Framework: Also, install the INET framework from the INET repository.
Step 2: Understand BGP and Classless Routing
BGP is a path-vector protocol used for inter-domain routing, which helps CIDR for efficient IP address allocation. BGP routers interchange routing information, which embraces IP prefixes and their associated attributes.
Step 3: Create the BGP Protocol Module
Define the Module in .ned File
For BGP protocol module, we have generate a .ned file.
simple BGP
{
parameters:
double updateInterval @unit(s) = default(30s);
gates:
input fromNetworkLayer;
output toNetworkLayer;
input fromMacLayer;
output toMacLayer;
}
Implement the Module in C++
Create the corresponding .cc and .h files.
BGP.h
#ifndef __BGP_H_
#define __BGP_H_
#include <omnetpp.h>
#include “inet/networklayer/contract/IRoutingTable.h”
#include “inet/networklayer/common/L3AddressResolver.h”
#include “inet/networklayer/ipv4/IPv4Datagram.h”
#include <map>
using namespace omnetpp;
using namespace inet;
class BGP : public cSimpleModule
{
private:
double updateInterval;
IRoutingTable *routingTable;
cMessage *updateMsg;
std::map<L3Address, std::string> routingTableMap; // Map to store IP prefixes and next hops
protected:
virtual void initialize() override;
virtual void handleMessage(cMessage *msg) override;
void sendRoutingUpdate();
void processRoutingUpdate(cMessage *msg);
public:
BGP();
virtual ~BGP();
};
#endif
BGP.cc
#include “BGP.h”
Define_Module(BGP);
BGP::BGP()
{
updateMsg = nullptr;
}
BGP::~BGP()
{
cancelAndDelete(updateMsg);
}
void BGP::initialize()
{
updateInterval = par(“updateInterval”);
routingTable = getModuleFromPar<IRoutingTable>(par(“routingTableModule”), this);
updateMsg = new cMessage(“sendRoutingUpdate”);
scheduleAt(simTime() + updateInterval, updateMsg);
}
void BGP::handleMessage(cMessage *msg)
{
if (msg == updateMsg)
{
sendRoutingUpdate();
scheduleAt(simTime() + updateInterval, updateMsg);
}
else
{
processRoutingUpdate(msg);
}
}
void BGP::sendRoutingUpdate()
{
cMessage *update = new cMessage(“RoutingUpdate”);
// Add routing information to the message
for (const auto &entry : routingTableMap)
{
update->addPar(entry.first.str().c_str()) = entry.second.c_str();
}
send(update, “toNetworkLayer”);
}
void BGP::processRoutingUpdate(cMessage *msg)
{
// Process received routing update
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 address(key);
routingTableMap[address] = value;
}
delete msg;
}
Step 4: Integrate with Simulation Model
In network simulation model, we have to assimilate the BGP module.
Network Configuration .ned File
network BGPNetwork
{
submodules:
router1: StandardHost {
parameters:
@display(“p=100,100”);
routingTableModule = “^.routingTable”;
}
router2: StandardHost {
parameters:
@display(“p=300,100”);
routingTableModule = “^.routingTable”;
}
// Add more routers as needed
connections:
router1.pppg++ <–> { @display(“m=100,100”); } <–> router2.pppg++;
}
omnetpp.ini Configuration
network = BGPNetwork
*.router*.pppg[*].queue.typename = “DropTailQueue”
*.router*.ipv4.routingTable = “inet.networklayer.routing.manet.Router”
*.router*.networkLayer.networkProtocol.typename = “IPv4NetworkLayer”
*.router*.transportLayer.tcp.typename = “Tcp”
*.router*.transportLayer.udp.typename = “Udp”
*.router*.application[*].typename = “UdpBasicApp”
*.router*.application[*].destAddresses = “router1” // Set destination as needed
*.router*.application[*].destPort = 2000
*.router*.application[*].startTime = uniform(0s, 10s)
*.router*.application[*].sendInterval = uniform(1s, 2s)
*.router*.application[*].packetLength = 512B
*.router*.app[0].typename = “BGP”
Step 5: Test and Debug
- Run Simulations: Execute simulations to examine the behavior of the BGP module under multiple network conditions.
- Analyze Results: Verify the correctness and performance of the execution.
- Debugging: we can troubleshoot the issues with the help of OMNeT++’s debugging tools.
This approach will guide you through implementing a simplified version of a classless routing protocol, such as BGP, in OMNeT++. We plan to provide the extra details on Classless protocol as per your requirements.
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