How to Start Centralized Routing Projects Using OMNeT++

To start a Centralized Routing project using OMNeT++ environment has need s to replicate a network where routing decisions are created by a central entity instead of individual routers. Routers transmit its network topology and link-state data to a central server or controller, which then calculates the best routing paths and delivers them again to the routers in a centralized routing mechanisms.

Below is a general method for Centralized Routing project using OMNeT++:

Steps to Start Centralized Routing Projects in OMNeT++

Step 1: Install OMNeT++ and INET Framework

  1. Download OMNeT++:
    • We should download and install the new version of OMNeT++ on the computer.
  2. Verify Installation:
    • After installation, we need to make and execute a basic example project to make sure that OMNeT++ is properly installed.
  3. Install INET Framework:
    • INET framework is a popular simulation framework for OMNeT++, which offers network protocols and models with routing protocols, traffic generators, and network devices.
    • We need to download and install INET using GitHub.
    • We can install INET via OMNeT++’s module manager or by coping the repository.

Step 2: Set Up a New OMNeT++ Project

  1. Create a New OMNeT++ Project:
    • Go to OMNeT++ IDE and select File > New > OMNeT++ Project.
    • Choose the “Simple Project” and name it to the project as CentralizedRouting.
  2. Create Network Topology:
    • We need to make the network topology using a .ned file. In this example, the topology can be contained the routers that are associated to each other and to hosts. We will require a centralized controller to perform like the routing server that will be compute the routes and interact with the routers.

Below is an instance of a simple network topology in .ned:

network CentralizedRoutingNetwork {

submodules:

controller: CentralizedController;

router1: Router;

router2: Router;

router3: Router;

host1: Host;

host2: Host;

connections:

host1.ethg++ <–> EthernetInterface <–> router1.ethg++;

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

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

router3.ethg++ <–> EthernetInterface <–> host2.ethg++;

}

In this example:

  • This is a centralized controller module (controller), which will manage the routing decisions.
  • It has 3 routers such as router1, router2, router3, and 2 hosts (host1, host2).

Step 3: Implement the Centralized Routing Logic

  1. Centralized Controller:
    • The central controller will be gathered the network topology data from routers, determine the best routing paths with the help of Dijkstra’s algorithm, and then transmit the routing data again to each router.
  2. Router Module:
    • Routers will perform like simple forwarding devices. They will be transmitted its link-state data or network topology data to the central controller and rely on the data that are obtained from the controller, modernize its routing table.

Example C++ Implementation

CentralizedController Module (C++)

class CentralizedController : public cSimpleModule {

private:

// Store link-state information received from routers

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

protected:

virtual void initialize() override {

// Initialization of the controller

}

virtual void handleMessage(cMessage *msg) override {

if (msg->isSelfMessage()) {

// Periodic control actions or link-state updates

} else {

// Handle received link-state information from routers

processLinkStateInformation(msg);

}

}

void processLinkStateInformation(cMessage *msg) {

// This function will parse the received link-state information and update the controller’s topology

// The message could be a custom message like LinkStateInformation

// After receiving the link-state information from routers, compute the routing table

// Example of computing the shortest paths using Dijkstra’s algorithm

computeRoutingTable();

}

void computeRoutingTable() {

// Implement Dijkstra’s algorithm or another centralized routing algorithm to calculate optimal paths

// The controller computes the routing table and sends it to the routers

// Example: For simplicity, assume we send routing updates to routers

sendRoutingUpdates();

}

void sendRoutingUpdates() {

// Send the computed routing information back to each router

// The routing table can be sent as a custom message with routing info

for (int routerId : getRouterIds()) {

cMessage *routingUpdate = new cMessage(“RoutingUpdate”);

// Fill the message with routing table information

send(routingUpdate, “out”);

}

}

std::vector<int> getRouterIds() {

// Return a list of router IDs (can be hardcoded or dynamically managed)

return {1, 2, 3};

}

};

Router Module (C++)

class Router : public cSimpleModule {

protected:

virtual void initialize() override {

// Initialization of the router (waiting for routing updates from the controller)

}

virtual void handleMessage(cMessage *msg) override {

if (msg->isSelfMessage()) {

// Handle periodic events (if any)

} else {

// Handle routing information update from the centralized controller

processRoutingUpdate(msg);

}

}

void processRoutingUpdate(cMessage *msg) {

// Process the routing table update from the centralized controller

// Update the router’s routing table

}

};

Centralized Routing Steps:

  1. Router Sends Link-State Information:
    • Every single router transmits their link-state data periodically that is its neighbors and link costs to the centralized controller.
  2. Controller Computes the Routing Table:
    • The centralized controller utilises the received link-state data determining the best routing paths with the support of Dijkstra’s or Bellman-Ford algorithms.
    • When the routing table is calculated then the controller transmits the updated routing paths again to the routers.
  3. Router Updates Its Routing Table:
    • Based on receiving the routing update from the controller, each router modernizes their routing table and it can be transmitted packets consequently.

Step 4: Define Custom Messages for Routing Updates

For link-state data or routing updates, delineate a custom message type. It might be a LinkStateInformation or RoutingUpdate message.

Example of a custom message class:

class RoutingUpdate : public cPacket {

public:

std::map<int, std::string> routingTable;  // Map of destination to next hop

RoutingUpdate() : cPacket(“RoutingUpdate”) {}

};

In this instance, the RoutingUpdate message should include the routing table that the router will be utilised to send packets.

Step 5: Configure the Simulation in omnetpp.ini

Set the simulation metrics like the network configuration, router settings, and application settings using the omnetpp.ini file.

Example omnetpp.ini configuration:

network = CentralizedRoutingNetwork

sim-time-limit = 100s

[Config CentralizedRouting]

*.controller.routingAlgorithm = “Centralized”

*.router1.routingProtocol = “Centralized”

*.router2.routingProtocol = “Centralized”

*.router3.routingProtocol = “Centralized”

# 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

This set up describes the routers and configures its routing protocol to Centralized. Also, it sets traffic for the hosts.

Step 6: Run and Observe the Simulation

  1. Compile and Run:
    • In OMNeT++ IDE, compile the project then execute the simulation.
    • Envision the routing decisions and packet flows to utilise Tkenv which is OMNeT++’s graphical interface.
  2. Debugging and Logging:
    • Make use of logging (EV) to monitor the centralized controller and routers behavior.
    • Monitor the link-state advertisements (LSAs) flow and the routing table modernizes.

Step 7: Extend and Optimize

  1. Scalability:
    • Experiment the centralized routing method including a larger network to monitor how the system measures. Deliberate to enhance the link-state collection and route calculation processes.
  2. Failure Recovery:
    • We need to execute the network failures like link or node failures and then monitor how the centralized controller re-calculates routes and modernizes the routers.
  3. Traffic Patterns:
    • Test with various traffic patterns such as UDP, TCP and verify the effect of centralized routing decisions on packet delivery.
  4. Performance Metrics:
    • Estimate the performance parameters like convergence time of routing protocol, control message overhead, and routing stability.

Conclusion

To make a Centralized Routing project encompasses to describe a network in which routers transmit its link-state data to a central controller using OMNeT++. This controller calculates the routing table and sends the best routing paths back to the routers. The OMNeT++ environment and INET frameworks offer a basis to replicate such centralized routing protocols, and we can be prolonged the simulation to experiment diverse topologies, traffic patterns, and failure conditions. If you want more advanced process on this topic, we will be provided.

Feel free to reach out to us, and we will provide you with the best guidance. At phdprojects.org, we are dedicated to helping you kickstart your Centralized Routing Projects using OMNeT++. We offer personalized topics that align with your interests. Our team is here to assist you with network topology and link-state data management to a central server or controller, ensuring you receive the highest level of support.