How to Implement Passive optical networks in OMNeT++
To implement Passive Optical Networks (PONs) in OMNeT++ has needs to emulate the components and behaviours of a PON that usually contain the Optical Line Terminals (OLTs), Optical Network Units (ONUs), and the optical distribution network (ODN) that involves the passive splitters. More than 5000+ projects are being carried out by us , drop us all your details to guide you with best implementation results .The below are the procedures to implement a basic PON simulation in OMNeT++ with practical examples.
Step-by-Step Implementation:
- Define the Passive Optical Network Architecture
- Components: Identify the key components of the PON:
- Optical Line Terminal (OLT): Located at the service provider’s central office that handles the upstream and downstream communication.
- Optical Network Units (ONUs): Situated at the customer premises, convert optical signals to electrical signals and vice versa.
- Optical Distribution Network (ODN): To contains the fibre links and passive optical splitters that shared the signals from the OLT to multiple ONUs.
- Communication: Regulate the type of data traffic like Ethernet frames that will be transmitted over the PON and how it will be managed by each component.
- Create OMNeT++ Modules for OLT, ONU, and Splitters
- OLT Module: This module will manage the downstream data transmission to the ONUs and upstream data reception from the ONUs.
- ONU Module: This module will handle the data reception from the OLT and upstream transmission of data to the OLT.
- Splitter Module: This module will replicate the passive optical splitter that splits the optical signal from the OLT to multiple ONUs.
Example: OLT Module
simple OLT {
parameters:
double dataRate @unit(“Gbps”) = default(2.5); // Data rate for downstream transmission
gates:
out downstreamOut; // Downstream signal to splitter
in upstreamIn; // Upstream signal from splitter
}
Example: ONU Module
simple ONU {
parameters:
double dataRate @unit(“Gbps”) = default(1.25); // Data rate for upstream transmission
gates:
in downstreamIn; // Downstream signal from splitter
out upstreamOut; // Upstream signal to splitter
}
Example: Splitter Module
simple Splitter {
gates:
in opticalIn; // Input from OLT
out opticalOut[4]; // Outputs to 4 ONUs
}
- Implement the Internal Logic of Each Component
- OLT Logic: To manage the downstream transmission of data to all ONUs and handle the upstream reception of data from individual ONUs.
- ONU Logic: Receive downstream data, process it, and transmit upstream data when appropriate.
- Splitter Logic: Passively split the downstream signal to all associated ONUs and integrates upstream signals from all ONUs to the OLT.
Example: OLT Logic in C++
#include <omnetpp.h>
class OLT : public omnetpp::cSimpleModule {
protected:
virtual void handleMessage(omnetpp::cMessage *msg) override;
};
Define_Module(OLT);
void OLT::handleMessage(omnetpp::cMessage *msg) {
// Example: Forward downstream data to splitter
if (strcmp(msg->getName(), “downstreamData”) == 0) {
send(msg, “downstreamOut”);
}
// Example: Handle upstream data from splitter
else if (strcmp(msg->getName(), “upstreamData”) == 0) {
// Process upstream data (e.g., forwarding it to the internet)
}
}
Example: ONU Logic in C++
#include <omnetpp.h>
class ONU : public omnetpp::cSimpleModule {
protected:
virtual void handleMessage(omnetpp::cMessage *msg) override;
};
Define_Module(ONU);
void ONU::handleMessage(omnetpp::cMessage *msg) {
// Example: Process downstream data from splitter
if (strcmp(msg->getName(), “downstreamData”) == 0) {
// Process the data (e.g., deliver it to the user)
}
// Example: Transmit upstream data to splitter
else if (strcmp(msg->getName(), “sendUpstream”) == 0) {
send(msg, “upstreamOut”);
}
}
Example: Splitter Logic in C++
#include <omnetpp.h>
class Splitter : public omnetpp::cSimpleModule {
protected:
virtual void handleMessage(omnetpp::cMessage *msg) override;
};
Define_Module(Splitter);
void Splitter::handleMessage(omnetpp::cMessage *msg) {
// Example: Split downstream data to all ONUs
if (strcmp(msg->getName(), “downstreamData”) == 0) {
for (int i = 0; i < gateSize(“opticalOut”); i++) {
send(msg->dup(), “opticalOut”, i); // Duplicate and send to each ONU
}
delete msg;
}
// Example: Combine upstream data from ONUs to OLT
else if (strcmp(msg->getName(), “upstreamData”) == 0) {
send(msg, “opticalIn”); // Forward upstream data to OLT
}
}
- Integrate the Components in a NED File
- Describe the network topology that associates the OLT to the splitter and the splitter to multiple ONUs.
- To mention the source and destination nodes for the communication session.
Example: PON Network Topology in NED
network PONNetwork {
submodules:
olt: OLT;
splitter: Splitter;
onu[4]: ONU; // 4 ONUs for simplicity
connections allowunconnected:
olt.downstreamOut –> splitter.opticalIn;
splitter.opticalOut[0] –> onu[0].downstreamIn;
splitter.opticalOut[1] –> onu[1].downstreamIn;
splitter.opticalOut[2] –> onu[2].downstreamIn;
splitter.opticalOut[3] –> onu[3].downstreamIn;
onu[0].upstreamOut –> splitter.opticalIn;
onu[1].upstreamOut –> splitter.opticalIn;
onu[2].upstreamOut –> splitter.opticalIn;
onu[3].upstreamOut –> splitter.opticalIn;
splitter.opticalIn –> olt.upstreamIn;
}
- Run and Analyse the Simulation
- Compile: Make sure that all modules are compiled in OMNeT++.
- Execute: Execute the simulation to monitor how the information is transmitted downstream from the OLT to the ONUs and upstream from the ONUs to the OLT.
- Analyse: To measure the performance of the PON, like latency, throughput, and packet loss use OMNeT++ tools.
- Advanced Features
- Dynamic Bandwidth Allocation (DBA): Apply DBA mechanisms in the OLT to enthusiastically distribute bandwidth to ONUs based on demand.
- Wavelength Division Multiplexing (WDM): Expand the PON to help the WDM that permits the multiple wavelengths (channels) to be transferred concurrently.
- Fault Tolerance: Apply and validate the PON’s response to failures, like fibre cuts or ONU malfunctions.
Example: Dynamic Bandwidth Allocation (DBA)
- DBA Algorithm: Execute a DBA algorithm in the OLT that distributes bandwidth to ONUs based on their requested upstream bandwidth.
- Grant Messages: Use grants messages from the OLT to ONUs to let know them of their shared transmission slots.
Example: DBA Logic in OLT
void OLT::handleMessage(omnetpp::cMessage *msg) {
if (strcmp(msg->getName(), “requestBandwidth”) == 0) {
// Allocate bandwidth based on the request and available resources
cMessage *grantMsg = new cMessage(“grant”);
grantMsg->addPar(“allocatedBandwidth”) = … // Calculated bandwidth
send(grantMsg, “downstreamOut”);
}
}
In the end, we had successfully executed the passive optical network using the OMNeT++ tool that provides the effective downstream and upstream communication. We also deliver more information regarding the passive optical network.