How to Simulate Network DTN architectures in OMNeT++

To implement the Delay-Tolerant Network (DTN) architectures in OMNeT++ required a nodes that should manage the high latency, intermittent connectivity and capable network partitions by simulating a network. This architecture is vital for the environments like traditional network protocol are inadequate includes in space communications, rural areas or disaster recovery situations. Here, we provided the step-by-step implementation of DTN architectures:

Step-by-Step Implementation:

1. Set Up OMNeT++ and INET Framework

• Install OMNeT++: Make certain that OMNeT++ is installed and configured on your system.
• Install INET Framework: For network communication, mobility and other essential elements, we have to set up a INET framework that offers some models.

2. Define the Network Topology

Start by generating a network topology in which their nodes are linked sporadically or have the capability of being disconnected. It will denote a DTN, where nodes use store-and-forward methods to pass messages.

Example NED File (DTNArchitecture.ned):

package mynetwork;

import inet.node.inet.StandardHost;

import inet.mobility.trails.TrailedMobility;

network DTNArchitecture

{

parameters:

int numNodes = default(5); // Number of DTN nodes

submodules:

dtnNode[numNodes]: StandardHost {

@display(“p=100,100;is=square,red”);

mobility: TrailedMobility {

displayStringTextFormat = “mov. t=${mobilityState}”;

trailId = default(“”);

anchorNode = default(“”);

updateInterval = 1s;

}

}

}

In this sample:

• dtnNode[]: Denotes different nodes that will execute DTN architecture, with mobility models that permit intermittent connectivity.

3. Implement DTN Architecture Protocol

You need to generate a custom protocol that executes the DTN architecture. This protocol should manage data storage, routing decisions, and the forwarding of messages when  connection turn out to be available.

Example: DTN Architecture Protocol (DTNProtocol.ned)

package mynetwork;

import inet.applications.base.ApplicationBase;

simple DTNProtocol extends ApplicationBase

{

gates:

input upperLayerIn;

output upperLayerOut;

input lowerLayerIn;

output lowerLayerOut;

}

DTNProtocol.cc (Basic Implementation)

#include “inet/common/INETDefs.h”

#include “inet/applications/base/ApplicationBase.h”

#include “inet/common/queue/FIFOQueue.h”

Define_Module(DTNProtocol);

void DTNProtocol::initialize(int stage) {

ApplicationBase::initialize(stage);

if (stage == INITSTAGE_LOCAL) {

storageCapacity = par(“storageCapacity”).intValue();

maxRetries = par(“maxRetries”).intValue();

bundleTimeout = par(“bundleTimeout”).doubleValue();

messageQueue = new cQueue(“messageQueue”);

scheduleAt(simTime() + bundleTimeout, processQueueEvent);

}

}

void DTNProtocol::handleMessageWhenUp(cMessage *msg) {

if (msg == processQueueEvent) {

processQueue();

scheduleAt(simTime() + bundleTimeout, processQueueEvent);

} else if (msg->getArrivalGate() == upperLayerIn) {

handleUpperMessage(msg);

} else {

handleLowerMessage(msg);

}

}

void DTNProtocol::handleUpperMessage(cMessage *msg) {

if (messageQueue->getLength() < storageCapacity) {

messageQueue->insert(msg);

EV << “Message stored. Queue size: ” << messageQueue->getLength() << “\n”;

} else {

EV << “Storage full. Dropping message.\n”;

delete msg;  // Drop the message if storage is full

}

}

void DTNProtocol::handleLowerMessage(cMessage *msg) {

// Handle message received from other DTN nodes

EV << “Received message: ” << msg->getName() << “\n”;

// You can decide to store, forward, or process the message

delete msg;

}

void DTNProtocol::processQueue() {

if (!messageQueue->isEmpty()) {

cMessage *message = check_and_cast<cMessage *>(messageQueue->pop());

if (canTransmit()) {

sendDown(message);

EV << “Message forwarded to the next node.\n”;

} else {

messageQueue->insert(message);  // Reinsert the message if it can’t be sent

EV << “No connection available. Reinserted message into the queue.\n”;

}

}

}

bool DTNProtocol::canTransmit() {

// Simulate the decision to transmit based on connection availability

return uniform(0, 1) > 0.5;  // Randomly allow or disallow transmission

}

void DTNProtocol::finish() {

// Clean up and finalize the simulation

delete messageQueue;

}

In this sample:

• messageQueue: Stores messages until they can be transmitted.
• processQueue(): Intermittently authorize the queue and tries to transmit messages if a connection is available.
• canTransmit(): States whether transmission is possible, simulating intermittent connectivity.

4. Configure the Simulation

Setting up the simulation in the omnetpp.ini file to use the custom DTN protocol.

Example Configuration in omnetpp.ini:

network = DTNArchitecture

**.dtnNode[*].applications[0].typename = “DTNProtocol”

**.dtnNode[*].applications[0].storageCapacity = 10

**.dtnNode[*].applications[0].maxRetries = 5

**.dtnNode[*].applications[0].bundleTimeout = 10s

5. Simulate and Monitor the DTN Architecture

Run the simulation and observe the DTN architecture in action. Find metrics like message delivery success rate, delay, and storage usage at the nodes.

Example Configuration for Monitoring Metrics:

network = DTNArchitecture

**.dtnNode[*].applications[0].numMessagesStored.recordScalar = true

**.dtnNode[*].applications[0].numMessagesForwarded.recordScalar = true

**.dtnNode[*].applications[0].numRetries.recordScalar = true

This configuration logs the number of messages stored, forwarded, and the number of retries, helping testing the efficiency of the DTN protocol.

6. Analyze and Optimize the DTN Architecture

After running the simulation, analyze the results to assess the performance of your DTN architecture. Consider factors like:

• Message Delivery Ratio: The percentage of successfully delivered messages.
• Delay: The average time taken to deliver messages.
• Storage Utilization: The efficiency of message storage at each node.

7. Extend the DTN Architecture

You can expand the simple DTN architecture with extra features like:

• Priority-based Message Handling: Execute priority levels for messages, making sure critical data is transmitted first.
• Multi-hop Routing: Implement routing algorithms that permit messages to traverse different nodes before reaching their destination.
• Adaptive Protocols: Generating protocols that adapt to varying network conditions, like changing node density or mobility patterns.

Example: Multi-hop Routing

void DTNProtocol::handleLowerMessage(cMessage *msg) {

EV << “Received message: ” << msg->getName() << “\n”;

if (isFinalDestination(msg)) {

EV << “Message delivered to final destination.\n”;

delete msg;

} else {

EV << “Forwarding message to the next hop.\n”;

messageQueue->insert(msg);  // Reinsert the message to forward later

}

}

bool DTNProtocol::isFinalDestination(cMessage *msg) {

// Placeholder logic for determining if the current node is the final destination

return uniform(0, 1) < 0.2;  // 20% chance that this node is the final destination

}

8. Document and Report Findings

After running the simulations, document the DTN strategies tested, the results gotten, and any optimizations made. This documentation will help in understanding the trade-offs and efficiency of several DTN architectures in wavering conditions.

Through this approach, we offered the overall information regarding the implementation of Network DTN architectures in OMNeT++ and the execution of some protocols which are provided by the INET framework. The specialists at Omnet-manual.com offer distinctive topics and insights, as well as support for network comparison analysis. To implement Network DTN architectures using the OMNeT++ tool, we are committed to providing you with exceptional guidance while we focus on traditional network protocols, ensuring personalized assistance throughout the process.