How to Start Dijkstra’s Link State Projects Using OMNeT++

To start a Dijkstra’s Link-State Routing project using OMNeT++, we want to replicate a network in which nodes or routers distribute its link-state data including other nodes to build a routing table with the support of Dijkstra’s algorithm. Dijkstra’s algorithm is frequently utilised for determining the shortest path from one node to every other node rely on link costs within the network.

Below is a stepwise approach how we can begin a Dijkstra’s Link-State Routing project using OMNeT++:

Steps to Start Dijkstra’s Link-State Routing Project in OMNeT++:

Step 1: Install OMNeT++ and INET Framework

  1. Download OMNeT++:
    • We should download and install the new version of OMNeT++ on the system.
  2. Verify Installation:
    • After installing OMNeT++, we need to make and execute an example project confirming that everything is properly functioning.
  3. Install INET Framework:
    • INET is a popular simulation framework with OMNeT++ to replicate the network protocols with routing protocols such as Dijkstra’s Link-State Routing. We download and install the INET framework using its GitHub link.
    • We able to install it via OMNeT++’s module manager or manually from the INET GitHub repository.

Step 2: Set Up a New OMNeT++ Project

  1. Create a New OMNeT++ Project:
    • Go to OMNeT++ IDE, choose File > New > OMNeT++ Project.
    • Decide on the “Simple Project” template and name it to the project as DijkstraLinkStateRouting.
  2. Create Network Topology:
    • In a .ned file, we need to create the network topology. We will contain routers (network nodes) that are associated by links for a link-state routing simulation.

Below  is an example of a basic network topology including three routers:

network DijkstraLinkStateNetwork {

submodules:

router1: Router;

router2: Router;

router3: Router;

connections:

router1.ethg++ <–> EthernetInterface <–> router2.ethg++;

router2.ethg++ <–> EthernetInterface <–> router3.ethg++;

router3.ethg++ <–> EthernetInterface <–> router1.ethg++;

}

In this case:

  • It contains three routers such as router1, router2, router3, which are associated within a triangle topology.

Step 3: Implement Dijkstra’s Link-State Routing Algorithm

  1. Define the Router Module:
    • Make a new module in which the Dijkstra’s Link-State Routing protocol will be executed for the router. It comprise of exchanging link-state advertisements (LSAs) including neighbors and to determine the shortest path.
  2. Dijkstra Algorithm:
    • Dijkstra algorithm will be calculated the shortest path to every other node depends on the link costs in each router. Routers will be transmitted its link-state data to their neighbors, and each router will be determined the shortest path to all other nodes.

Below is a basic implementation in C++:

class LinkStateRouter : public cSimpleModule {

private:

// Data structure to store link state information (e.g., a routing table)

std::map<int, std::vector<std::pair<int, double>>> linkStateTable; // {node, {neighbor, cost}}

protected:

virtual void initialize() override {

// Initialize the router, exchange link state advertisements (LSAs)

}

virtual void handleMessage(cMessage *msg) override {

if (msg->isSelfMessage()) {

// Handle periodic link-state updates

sendLinkStateAdvertisement();

} else {

// Handle incoming LSA

processLinkStateAdvertisement(msg);

}

}

void sendLinkStateAdvertisement() {

// Broadcast the link state information (LSA) to neighbors

cMessage *lsa = new cMessage(“LSA”);

// Set LSA contents (this would include link cost and neighbors)

send(lsa, “out”);  // Send LSA to all neighbors

}

void processLinkStateAdvertisement(cMessage *msg) {

// Parse and update link state table from received LSA

// Apply Dijkstra’s algorithm to calculate the shortest path

// For simplicity, assume the received message contains a link-state advertisement

// Example: simple Dijkstra algorithm to compute shortest paths

computeShortestPaths();

}

void computeShortestPaths() {

// Implement Dijkstra’s algorithm to compute the shortest path

// to all other nodes based on the link state table

// This will update the router’s routing table

// Example Dijkstra implementation (simplified)

std::vector<int> nodes = getAllNodes();

std::map<int, double> dist;

std::map<int, int> prev;

for (int node : nodes) {

dist[node] = INFINITY;

prev[node] = -1;

}

dist[myNodeId()] = 0;

while (!nodes.empty()) {

// Find node with the minimum distance

int u = findMinDistanceNode(nodes, dist);

nodes.erase(std::remove(nodes.begin(), nodes.end(), u), nodes.end());

// Update distances for neighbors of u

for (auto neighbor : linkStateTable[u]) {

int v = neighbor.first;

double weight = neighbor.second;

if (dist[u] + weight < dist[v]) {

dist[v] = dist[u] + weight;

prev[v] = u;

}

}

}

// The “dist” map now holds the shortest distances from myNodeId() to all other nodes

}

int findMinDistanceNode(std::vector<int> &nodes, const std::map<int, double> &dist) {

// Return the node with the minimum distance

int minNode = -1;

double minDistance = INFINITY;

for (int node : nodes) {

if (dist.at(node) < minDistance) {

minDistance = dist.at(node);

minNode = node;

}

}

return minNode;

}

std::vector<int> getAllNodes() {

// Return the list of all nodes in the network

return {1, 2, 3};  // Simplified for this example

}

int myNodeId() {

// Return the ID of the current router (node)

return 1;  // Example node ID

}

};

In this execution:

  • Link-state table is a map in which each node save their neighbors and the cost attaining them.
  • Utilise Dijkstra’s algorithm for calculating the shortest path.
  • Self-messages are utilised to transmit the link-state advertisements (LSAs) periodically to neighbors.
  • LSAs are executed and the routing table is modernized.

Step 4: Define Link-State Advertisements (LSA)

The Link-State Advertisement (LSA) is the message swapped among the routers to update them of the network’s present state. Each LSA has:

  • The router ID.
  • A list of neighboring routers and link costs.

LSAs can be executed like custom message classes in OMNeT++. We can be described an LSA message as follows:

class LinkStateAdvertisement : public cPacket {

public:

int routerId;

std::vector<std::pair<int, double>> linkStateInfo; // {neighbor, cost}

LinkStateAdvertisement() : cPacket(“LSA”) {}

};

Then, we can be utilised this class to transmit and obtain the LSAs within router module.

Step 5: Configure Simulation in omnetpp.ini

Describe the simulation metrics such as routing protocols, network topology, link costs, and application settings within the omnetpp.ini file.

Example set up for a simple Dijkstra link-state simulation:

network = DijkstraLinkStateNetwork

sim-time-limit = 100s

[Config Router]

*.router1.routingProtocol = “Dijkstra”

*.router2.routingProtocol = “Dijkstra”

*.router3.routingProtocol = “Dijkstra”

# Define application traffic if necessary (e.g., UDP traffic between hosts)

*.host1.app[0].typename = “UdpBasicApp”

*.host1.app[0].destAddr = “host2”

*.host1.app[0].startTime = 1s

*.host1.app[0].messageLength = 1000B

*.host1.app[0].numMessages = 100

Step 6: Run and Observe the Simulation

  1. Compile and Run:
    • In OMNeT++ IDE, we execute the simulation.
    • Monitor the routing behavior and packet flow to utilise Tkenv which is OMNeT++’s graphical interface.
  2. Debugging and Logging:
    • In the C++ code, integrate the logging using EV to result debugging data.
    • Observe the routing table and the link-state advertisements (LSAs) flow.
  3. Metrics:
    • We need to monitor diverse parameters like the volume of forwarded packets, the routing table size, or the convergence time of the routing protocol.

Step 7: Extend and Optimize

  • Multiple Nodes: Maximize the volume of routers and then experiment the Dijkstra’s algorithm’s scalability.
  • Link Failures: We have to replicate link failures and also monitor how the network adjusts to new routes with the help of link-state protocol.
  • Performance Metrics: Estimate the convergence time, overhead by reason of link-state updates, and the Dijkstra’s algorithm effectiveness.
  • Traffic Patterns: Make use of various traffic patterns like UDP or TCP applications, to monitor how the routing protocol performs under pressure.

Conclusion

To make a Dijkstra’s Link-State Routing project needs to execute the Dijkstra algorithm for determining the shortest path within a network according to the link-state advertisements using OMNeT++. The INET framework make easier to several features of the network model whereas custom C++ code permits to replicate the Dijkstra algorithm and to handle the exchange of link-state data among the routers.

To kick off your Dijkstra’s Link-State Routing project, we at phdprojects.org are here to provide you with the best guidance and customized topics based on your interests. We handle network topology and link-state data to a central server or controller, ensuring you receive top-notch support. Just send us a message, and we’ll offer you the best advice possible.