How to Begin Implement Epidemic Protocol in NS3

To execute an Epidemic Protocol using NS3 which needs to replicate the probabilistic and opportunistic communication protocol behavior that frequently utilized within delay-tolerant networks (DTNs). The Epidemic Protocol enables message broadcasting by simulating the messages once nodes meet each other, which is same to how infections broadcast within an epidemic.

Here’s a detailed instruction on how we can execute it in NS3:

Steps to Begin Implement Epidemic Protocol in NS3

Step 1: Understand the Epidemic Protocol

1. Protocol Overview:
   • Nodes are swap messages which is named as “carriers” once they inherit contact.
   • Messages are simulated for increasing the delivery probability within networks including intermittent connectivity.
   • A message is removed when it attains their destination or a time-to-live (TTL) expires.
2. Key Components:
   • Message Buffer: Every single node sustains a buffer to save messages.
   • Encounter Detection: Nodes are determining the other nodes in broadcast range.
   • Message Exchange: Nodes opportunistically swap and simulate the messages.

Step 2: Set Up NS3

1. Download and Install NS3:
   • Replicate the repository and construct 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 simple example simulation script:

./ns3 run examples/tutorial/first

Step 3: Design the Epidemic Protocol

1. Data Structures:
   • Message Buffer: Save messages using metadata such as ID, TTL, and destination.
   • Encounter History: Monitor which nodes already contain inherited messages.
2. Behavior:
   • Once two nodes meet each other, then:
     • Swap the buffers for computing which messages absences the other node.
     • Export the lost messages.
   • Eliminate the messages, which are passed away.
3. Core Functions:
   • Message Creation: Make messages on the source nodes.
   • Message Propagation: During node meets, we distribute messages.
   • Message Expiry: Eliminate messages once TTL pass away.

Step 4: Implement the Epidemic Protocol

Step 4.1: Define the Protocol Class

Make a new protocol class to prolong an Application in the network:

#include “ns3/application.h”

#include “ns3/node.h”

#include “ns3/socket.h”

#include “ns3/mobility-module.h”

using namespace ns3;

class EpidemicProtocol : public Application {

public:

static TypeId GetTypeId(void);

EpidemicProtocol();

virtual ~EpidemicProtocol();

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 SendMessages(Ptr<Node> otherNode);

void ReceiveMessages();

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

Ptr<Socket> m_socket;

};

Step 4.2: Implement Protocol Logic

• Start and Stop the Protocol:

void EpidemicProtocol::StartApplication() {

// Initialize socket and schedule encounter detection

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

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

}

void EpidemicProtocol::StopApplication() {

m_socket->Close();

}

• Detect and Handle Encounters:

void EpidemicProtocol::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 encounter range

HandleEncounter(node);

}

}

}

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

}

• Exchange Messages:

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

// Send missing messages to the encountered node

SendMessages(otherNode);

}

void EpidemicProtocol::SendMessages(Ptr<Node> otherNode) {

// Implement message exchange logic here

}

Step 5: Simulate the Protocol

Step 5.1: Set Up Simulation Topology

Make a simulation topology in which nodes transfer and it can be met each other:

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<EpidemicProtocol> protocol = CreateObject<EpidemicProtocol>();

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

protocol->SetStartTime(Seconds(1.0));

protocol->SetStopTime(Seconds(100.0));

}

Simulator::Run();

Simulator::Destroy();

return 0;

}

Step 6: Test and Analyze

1. Testing:
   • Record the message transmissions and responses.
   • Confirm the functionality of protocol to leverage tracing.
2. Performance Metrics:
   • Delivery ratio: Estimate the volume of messages / total messages which are effectively distributed.
   • Overhead: Count the amount of copying message.
   • Latency: Measure the duration to attain the destination for messages.

Step 7: Extend and Optimize

1. Enhancements:
   • Integrate the message prioritization based on TTL.
   • Execute probabilistic forwarding for minimizing overhead.
   • Launch buffer management to manage the restricted storage.
2. Validation:
   • Experiment with diverse mobility patterns and node densities.
   • Replicate the real-world scenarios such as disaster recovery networks.

In conclusion, we comprehensively offered the brief explanation with their examples coding on how to approach the implementation of Epidemic Protocol which is executed and analyzed in NS3 environment. We plan to offer additional insights through another manual, if necessary.