How to implement OSI layer protocol in OMNeT++
To Implement an OSI layer protocol in OMNeT++ has needs to generate modules that emulate the characteristics of protocols at numerous layers of the OSI model from the physical layer to the application layer. The given below is the detailed procedure on how to implement the OSI layer protocol in OMNeT++;
Step-by-Step Implementation:
Step 1: Set Up OMNeT++ and INET Framework
- Install OMNeT++: Download and install the latest version of OMNeT++ from the OMNeT++
- Install INET Framework: Download and install the INET framework from the INET repository.
Step 2: Define the OSI Layer Protocol
We need to execute a protocol at the transport layer, same as a simplified version of TCP.
Define the Module in .ned File
Create a .ned file for the transport layer protocol module.
simple TransportLayerProtocol
{
parameters:
@display(“i=block/layer3”);
gates:
input fromNetworkLayer;
output toNetworkLayer;
input fromApplicationLayer;
output toApplicationLayer;
}
Implement the Module in C++
Create the corresponding .cc and .h files.
TransportLayerProtocol.h
#ifndef __TRANSPORTLAYERPROTOCOL_H_
#define __TRANSPORTLAYERPROTOCOL_H_
#include <omnetpp.h>
#include “inet/common/INETDefs.h”
#include “inet/networklayer/contract/INetfilter.h”
#include “inet/networklayer/common/L3Address.h”
#include “inet/networklayer/common/L3AddressResolver.h”
#include “inet/transportlayer/contract/TransportHeader_m.h”
#include <map>
using namespace omnetpp;
using namespace inet;
class TransportLayerProtocol : public cSimpleModule
{
private:
std::map<int, L3Address> connectionTable; // Stores connection info
int nextConnId;
protected:
virtual void initialize() override;
virtual void handleMessage(cMessage *msg) override;
void handleAppMessage(cMessage *msg);
void handleNetworkMessage(cMessage *msg);
void sendToNetwork(cPacket *packet, const L3Address &destAddr);
void sendToApp(cPacket *packet, int connId);
public:
TransportLayerProtocol();
virtual ~TransportLayerProtocol();
};
#endif
TransportLayerProtocol.cc
#include “TransportLayerProtocol.h”
Define_Module(TransportLayerProtocol);
TransportLayerProtocol::TransportLayerProtocol() : nextConnId(0)
{
}
TransportLayerProtocol::~TransportLayerProtocol()
{
}
void TransportLayerProtocol::initialize()
{
}
void TransportLayerProtocol::handleMessage(cMessage *msg)
{
if (msg->arrivedOn(“fromApplicationLayer”))
{
handleAppMessage(msg);
}
else if (msg->arrivedOn(“fromNetworkLayer”))
{
handleNetworkMessage(msg);
}
else
{
delete msg;
}
}
void TransportLayerProtocol::handleAppMessage(cMessage *msg)
{
cPacket *packet = check_and_cast<cPacket *>(msg);
int connId = nextConnId++;
L3AddressdestAddr=L3AddressResolver().resolve(packet>par(“destAddr”).stringValue());
connectionTable[connId] = destAddr;
sendToNetwork(packet, destAddr);
}
void TransportLayerProtocol::handleNetworkMessage(cMessage *msg)
{
cPacket *packet = check_and_cast<cPacket *>(msg);
int connId = packet->par(“connId”).intValue();
if (connectionTable.find(connId) != connectionTable.end())
{
sendToApp(packet, connId);
}
else
{
delete packet;
}
}
void TransportLayerProtocol::sendToNetwork(cPacket *packet, const L3Address &destAddr)
{
packet->addPar(“connId”) = nextConnId – 1;
send(packet, “toNetworkLayer”);
}
void TransportLayerProtocol::sendToApp(cPacket *packet, int connId)
{
send(packet, “toApplicationLayer”);
}
Step 3: Integrate with Simulation Model
Incorporate TransportLayerProtocol module inside a network simulation model.
Network Configuration .ned File
Create a .ned file to define the network topology.
network OSIModelNetwork
{
parameters:
@display(“bgb=600,400”);
submodules:
host1: StandardHost {
parameters:
@display(“p=100,200”);
}
host2: StandardHost {
parameters:
@display(“p=300,200”);
}
router: Router {
parameters:
@display(“p=200,100”);
}
connections:
host1.pppg++ <–> Eth10M <–> router.pppg++;
host2.pppg++ <–> Eth10M <–> router.pppg++;
}
Step 4: Configure the Simulation
Configure the simulation parameters in the omnetpp.ini file.
network = OSIModelNetwork
*.host*.pppg[*].queue.typename = “DropTailQueue”
*.host*.ipv4.routingTable = “inet.networklayer.routing.manet.Router”
*.host*.networkLayer.networkProtocol.typename = “Ipv4NetworkLayer”
*.host*.transportLayer.tcp.typename = “Tcp”
*.host*.transportLayer.udp.typename = “Udp”
*.host*.application[*].typename = “UdpBasicApp”
*.host*.application[*].destAddresses = “host1” // Set destination as needed
*.host*.application[*].destPort = 2000
*.host*.application[*].startTime = uniform(0s, 10s)
*.host*.application[*].sendInterval = uniform(1s, 2s)
*.host*.application[*].packetLength = 512B
*.host1.app[0].typename = “TransportLayerProtocol”
*.host2.app[0].typename = “TransportLayerProtocol”
Step 5: Test and Debug
- Run Simulations: Implement simulations to validate the characteristics of TransportLayerProtocol module under numerous network conditions.
- Analyse Results: Validate the correctness and performance of implementation.
- Debugging: Use OMNeT++’s debugging tools to troubleshoot any difficulties.
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