How to Begin Implement DTN Protocols in NS3

To execute the Delay Tolerant Network (DTN) protocols utilising NS3, we focusing on making or prolonging the routing and transmitting approaches, which contain intermittent connectivity, long delays, and asynchronous interaction. DTN protocols such as Epidemic, Spray and Wait, or Prophet are frequently utilized within scenarios like disaster recovery, deep-space interaction, or mobile ad hoc networks.

Below is a series of steps to start executing the DTN protocols in NS3:

Steps to Begin Implement DTN Protocols in NS3

Step 1: Understand DTN Concepts

1. Core DTN Features:
   • Bundle Protocol: It is a DTN-specific protocol, which manages the message forwarding.
   • Store-and-Forward Mechanism: Nodes save messages within buffers in anticipation of a forwarding opportunity occurs.
   • Custody Transfer: Makes sure that data is consistently delivered to the next node.
2. DTN Protocol Variants:
   • Epidemic Routing: It transmits messages to every encountered node.
   • Spray and Wait: Restricts the volume of message copies for managing the overhead.
   • Prophet Routing: It utilizes probabilistic parameters to send decisions.

Step 2: Set Up NS3

1. Download and Install NS3:

git clone https://gitlab.com/nsnam/ns-3-dev.git

cd ns-3-dev

./ns3 configure –enable-examples –enable-tests

./ns3 build

1. Verify Installation: Execute a basic example simulation script for verifying the installation:

./ns3 run examples/tutorial/first

Step 3: Plan Your DTN Protocol

1. Define Protocol Goals:
   • Specify type of DTN protocol to execute like Epidemic, Spray and Wait.
   • Describe the parameters or heuristics will direct the message transmitting decisions.
2. Core Functionalities:
   • Buffer Management: Save messages uisng metadata such as TTL, destination.
   • Encounter Handling: Describe how nodes are swap messages based on the contact.
   • Forwarding Strategy: Execute the logic to selecting which messages to send.

Step 4: Implement the DTN Protocol

Step 4.1: Define the Protocol Class

Make a new protocol class, which prolongs an Application or a related NS3 base class:

#include “ns3/application.h”

#include “ns3/node.h”

#include “ns3/socket.h”

using namespace ns3;

class DtnProtocol : public Application {

public:

static TypeId GetTypeId(void);

DtnProtocol();

virtual ~DtnProtocol();

void AddMessage(uint32_t messageId, uint32_t destination, uint32_t ttl);

void HandleEncounter(Ptr<Node> otherNode);

private:

virtual void StartApplication() override;

virtual void StopApplication() override;

void DetectEncounters();

void ForwardMessages(Ptr<Node> otherNode);

void ReceiveMessages();

std::map<uint32_t, std::pair<uint32_t, uint32_t>> m_messageBuffer; // MessageID -> (Destination, TTL)

Ptr<Socket> m_socket;

};

Step 4.2: Implement Protocol Logic

• Start and Stop Methods: Set sockets and schedule which meet detection using these mechanisms.

void DtnProtocol::StartApplication() {

m_socket = Socket::CreateSocket(GetNode(), TypeId::LookupByName(“ns3::UdpSocketFactory”));

Simulator::Schedule(Seconds(1.0), &DtnProtocol::DetectEncounters, this);

}

void DtnProtocol::StopApplication() {

m_socket->Close();

}

• Detect and Handle Encounters: Confirm periodically for neighbouring nodes and swap messages.

void DtnProtocol::DetectEncounters() {

Ptr<MobilityModel> mobility = GetNode()->GetObject<MobilityModel>();

for (auto node : NodeList::GetNodeList()) {

if (node != GetNode()) {

Ptr<MobilityModel> otherMobility = node->GetObject<MobilityModel>();

double distance = mobility->GetDistanceFrom(otherMobility);

if (distance < 10.0) { // Example contact range

HandleEncounter(node);

}

}

}

Simulator::Schedule(Seconds(1.0), &DtnProtocol::DetectEncounters, this);

}

void DtnProtocol::HandleEncounter(Ptr<Node> otherNode) {

ForwardMessages(otherNode);

}

• Forward and Receive Messages: Execute the logic for message exchange and buffer modernizes.

void DtnProtocol::ForwardMessages(Ptr<Node> otherNode) {

// Send messages that the other node lacks

}

void DtnProtocol::ReceiveMessages() {

// Add received messages to the buffer

}

Step 5: Simulate the DTN Protocol

Step 5.1: Define the Topology

Replicate an intermittent connectivity utilising mobility patterns:

int main(int argc, char *argv[]) {

NodeContainer nodes;

nodes.Create(10); // Create 10 nodes

MobilityHelper mobility;

mobility.SetMobilityModel(“ns3::RandomWalk2dMobilityModel”);

mobility.Install(nodes);

InternetStackHelper stack;

stack.Install(nodes);

for (uint32_t i = 0; i < nodes.GetN(); ++i) {

Ptr<DtnProtocol> dtn = CreateObject<DtnProtocol>();

nodes.Get(i)->AddApplication(dtn);

dtn->SetStartTime(Seconds(1.0));

dtn->SetStopTime(Seconds(100.0));

}

Simulator::Run();

Simulator::Destroy();

return 0;

}

Step 6: Validate and Test

1. Validation:
   • Record message exchanges, making sure that the protocol properly functions.
   • Confirm message delivery rates, latency, and overhead for validation.
2. Metrics to Analyze:
   • Delivery Ratio: Compare the delivered messages vs. total messages.
   • Overhead Ratio: Count the volume of message copies which are created.
   • Latency: Estimate duration for a message, attaining their destination.

Step 7: Extend and Optimize

1. Enhance Features:
   • For restricted storage, we can execute the buffer management.
   • Integrate probabilistic parameters or heuristic-based forwarding decisions.
   • Mimic realistic contact models such as social network-inspired mobility patterns.
2. Performance Optimization:
   • Experiment the protocol within larger networks.
   • Assess their performance in various node densities and mobility models.

As demonstrated above regarding the entire implementation process with example and its extension that helps you to execute the DTN Protocols in NS3 tool. If you want any details about DTN or the execution steps, we will offer you.