To simulate an Extended Star Topology within OMNeT++ that contains configuring a hierarchical network in which numerous star topologies are interconnected. In an extended star topology, several star networks are connected through central nodes or switches that permits communication among distinct sub-networks. This topology is generally utilized in larger networks like enterprise networks in which local star topologies are connected via a backbone network.
Now, we deliver a step-by-step instructions on how to simulate an Extended Star Topology in OMNeT++:
Steps to Simulate Extended Star Topology Projects in OMNeT++
- Design the Extended Star Topology
An extended star topology is fundamentally numerous star topologies are connected to a central node or hub. For instance:
- Each star topology involves multiple nodes are connected to a central switch or hub.
- The central hubs or switches of each star are then connected to a backbone switch or router.
- Define the Extended Star Network Structure (NED File)
In this instance, we will make two local star topologies, each connected to a central hub. Then, these hubs are associated to a backbone switch, forming the extended star topology.
Sample NED File (ExtendedStarTopology.ned)
network ExtendedStarTopology
{
submodules:
// Define the backbone switch that connects the two star networks
backboneSwitch: Node {
@display(“p=300,100”);
}
// Define the central switches for each star topology
starSwitch1: Node {
@display(“p=150,200”);
}
starSwitch2: Node {
@display(“p=450,200”);
}
// Define nodes for Star Topology 1 (connected to starSwitch1)
star1Node1: Node {
@display(“p=100,300”);
}
star1Node2: Node {
@display(“p=200,300”);
}
star1Node3: Node {
@display(“p=150,350”);
}
// Define nodes for Star Topology 2 (connected to starSwitch2)
star2Node1: Node {
@display(“p=400,300”);
}
star2Node2: Node {
@display(“p=500,300”);
}
star2Node3: Node {
@display(“p=450,350”);
}
connections allowunconnected:
// Connect each node in Star 1 to starSwitch1
star1Node1.out++ –> starSwitch1.in++;
starSwitch1.out++ –> star1Node1.in++;
star1Node2.out++ –> starSwitch1.in++;
starSwitch1.out++ –> star1Node2.in++;
star1Node3.out++ –> starSwitch1.in++;
starSwitch1.out++ –> star1Node3.in++;
// Connect each node in Star 2 to starSwitch2
star2Node1.out++ –> starSwitch2.in++;
starSwitch2.out++ –> star2Node1.in++;
star2Node2.out++ –> starSwitch2.in++;
starSwitch2.out++ –> star2Node2.in++;
star2Node3.out++ –> starSwitch2.in++;
starSwitch2.out++ –> star2Node3.in++;
// Connect the two central star switches to the backbone switch
starSwitch1.out++ –> backboneSwitch.in++;
backboneSwitch.out++ –> starSwitch1.in++;
starSwitch2.out++ –> backboneSwitch.in++;
backboneSwitch.out++ –> starSwitch2.in++;
}
- Define the Node Module (Node.ned)
Each node will require input and output gates for transmitting and receiving messages. Here is the Node.ned file, which describes these gates.
Sample Node Module (Node.ned)
simple Node
{
parameters:
@display(“i=device/laptop”); // Use a device icon for visualization
gates:
input in[];
output out[];
}
- Implement Node Behavior (Node.cc)
Each node in the star topology will transmit messages to its central switch, and the switches will forward messages to other nodes in their star topology or across to the other star through the backbone switch.
Sample Node Behavior (Node.cc)
#include <omnetpp.h>
using namespace omnetpp;
class Node : public cSimpleModule
{
private:
bool isSwitch; // If the node is a switch (central node in the star topology)
bool isBackboneSwitch; // If the node is the backbone switch
protected:
virtual void initialize() override;
virtual void handleMessage(cMessage *msg) override;
void forwardToStar(cMessage *msg); // Function to send messages within the star
void forwardToBackbone(cMessage *msg); // Function to send messages across stars
};
Define_Module(Node);
void Node::initialize()
{
// Determine if the node is a central switch or backbone switch
isSwitch = (strcmp(getName(), “starSwitch1”) == 0 || strcmp(getName(), “starSwitch2”) == 0);
isBackboneSwitch = (strcmp(getName(), “backboneSwitch”) == 0);
// Initiate a message from one of the nodes
if (strcmp(getName(), “star1Node1”) == 0) {
// Node in the first star initiates communication
cMessage *msg = new cMessage(“Message from star1Node1″);
scheduleAt(simTime() + 1.0, msg); // Send after 1 second
}
}
void Node::handleMessage(cMessage *msg)
{
if (isSwitch) {
// Central switch in the star forwards messages to other star nodes or backbone
forwardToBackbone(msg); // Forward the message to the backbone switch
} else if (isBackboneSwitch) {
// Backbone switch forwards messages to the other star network
forwardToStar(msg); // Forward message to the appropriate star switch
} else {
// Regular nodes process the received message
EV << getName() << ” received: ” << msg->getName() << “\n”;
delete msg; // Process the message and delete it
}
}
void Node::forwardToStar(cMessage *msg)
{
// Forward the message to all connected star nodes (broadcast within star)
for (int i = 0; i < gateSize(“out”); i++) {
cMessage *dupMsg = msg->dup(); // Duplicate the message for each node
EV << “Backbone switch forwarding to star node.\n”;
send(dupMsg, “out”, i);
}
delete msg;
}
void Node::forwardToBackbone(cMessage *msg)
{
// Forward the message to the backbone switch
EV << “Star switch forwarding to backbone switch.\n”;
send(msg, “out”, 0); // Send to the backbone
}
- Run the Simulation
We require an omnetpp.ini configuration file to identify the simulation parameters, containing the amount of gates each node will have and how long the simulation should run.
Sample OMNeT++ Configuration (omnetpp.ini)
[General]
network = ExtendedStarTopology
sim-time-limit = 10s
# Node-specific configurations
*.backboneSwitch.numGates = 2 # Backbone switch connects to two central star switches
*.starSwitch1.numGates = 3 # StarSwitch1 connects to 3 star nodes and the backbone switch
*.starSwitch2.numGates = 3 # StarSwitch2 connects to 3 star nodes and the backbone switch
*.star1Node*.numGates = 1 # Star nodes connect to only their star switch
*.star2Node*.numGates = 1 # Star nodes connect to only their star switch
- Visualize and Analyze
- Message Flow: We should observe messages originating from star1Node1 being forwarded to the central star switch (starSwitch1), and then to the backbone switch that routes it to the second star network (starSwitch2), in which other nodes can receive it.
- Performance Metrics: We can examine message delays, network congestion, and message propagation across distinct star networks in the extended star topology.
- Enhance the Simulation
Here are some ways to improve this simulation:
- Bidirectional Communication
Permit the nodes to react to messages, making bidirectional communication among the nodes in distinct star networks.
void Node::handleMessage(cMessage *msg)
{
if (!isSwitch && !isBackboneSwitch) {
// Leaf node processes the message and sends a reply
EV << “Node ” << getName() << ” processing and replying.\n”;
cMessage *response = new cMessage(“Response from ” + std::string(getName()));
send(response, “out”, 0); // Send response to the star switch
} else {
// Regular forwarding behavior for switches
…
}
}
- Load Balancing
We can replicate traffic load balancing by distributing messages across distinct links and observing network performance.
- Failure Simulation
Replicate node or link failures to investigate the robustness of the network. For instance, replicate a failure in the backbone switch and observe how it affects communication.
void Node::handleMessage(cMessage *msg)
{
if (isBackboneSwitch && uniform(0, 1) < 0.1) {
// Simulate a failure with a 10% probability
EV << “Backbone switch failed to process message.\n”;
delete msg;
} else {
// Normal processing
…
}
}
- Traffic Load Simulation
Make a distinct traffic patterns to replicate real-world network load, for instance, by having several nodes are transmit messages at random intervals.
void Node::initialize()
{
if (!isSwitch && !isBackboneSwitch) {
cMessage *msg = new cMessage(“Random Traffic”);
scheduleAt(simTime() + uniform(1, 5), msg); // Random traffic generation
}
}
- Example Use Case: Enterprise Network Simulation
An extended star topology can be replicated an enterprise network in which distinct departments (each represented by a local star network) are connected via a central backbone network. Each department communicates internally through its own star topology and externally via the backbone.
We distributed the appropriate technique to easily understand the core ideas on how to execute and simulate the Extended Star Topology projects then we also offered essential instances for this projects. If you acquire any queries on this topic, feel free to ask!
We will assist you with the detailed steps to conduct simulations in Extended Star Topology Projects using the OMNeT++ tool and ensure optimal results. If required, we will provide additional information on this topic in your specified area, along with the simulation results
