To simulate a Hybrid Topology in OMNeT++, which includes aggregating several kinds of network topologies (such as Bus, Star, Ring, and Mesh) into one comprehensive network. A hybrid topology can be signified real-world networks more exactly, as they frequently utilize distinct topologies for distinct parts of the network. For instance, a company might use a star topology in individual departments however connect those departments using a ring topology.
We will guide you through simulation process on how to simulate a Hybrid Topology in OMNeT++:
Steps to Simulate Hybrid Topology Projects in OMNeT++
- Design the Hybrid Topology Structure
In this instance, we will be replicated a hybrid network, which aggregates a star topology and a ring topology. We can change this according to the particular requirements of the project by inserting or combining other topologies such as bus or mesh.
- Star Topology: Numerous nodes are connected to a central hub (switch/router).
- Ring Topology: Nodes are connected in a circular manner, in which each node connects to accurately two other nodes.
- Create the Network Structure (NED File)
We will be described the hybrid network in the .ned file. This hybrid network include two main parts:
- A star network segment in which numerous leaf nodes are connect to a central switch.
- A ring network, which connects distinct segments or clusters.
Sample NED File (HybridTopology.ned)
network HybridTopology
{
submodules:
// Define the star topology with a central switch
switch: Node {
@display(“p=300,100”);
}
// Define several nodes connected to the central switch
starNode1: Node {
@display(“p=150,200”);
}
starNode2: Node {
@display(“p=250,200”);
}
starNode3: Node {
@display(“p=350,200”);
}
starNode4: Node {
@display(“p=450,200”);
}
// Define the ring topology
ringNode1: Node {
@display(“p=200,300”);
}
ringNode2: Node {
@display(“p=300,300”);
}
ringNode3: Node {
@display(“p=400,300”);
}
connections allowunconnected:
// Connect the star nodes to the central switch
starNode1.out++ –> switch.in++;
switch.out++ –> starNode1.in++;
starNode2.out++ –> switch.in++;
switch.out++ –> starNode2.in++;
starNode3.out++ –> switch.in++;
switch.out++ –> starNode3.in++;
starNode4.out++ –> switch.in++;
switch.out++ –> starNode4.in++;
// Connect the ring nodes in a circular fashion
ringNode1.out++ –> ringNode2.in++;
ringNode2.out++ –> ringNode3.in++;
ringNode3.out++ –> ringNode1.in++;
// Connect the switch to the ring topology (Hybrid connection)
switch.out++ –> ringNode1.in++;
ringNode1.out++ –> switch.in++;
}
- Create Node Module (Node.ned)
Each node in the network will be required to transmit and receive messages. Here’s the Node definition:
Sample Node Module (Node.ned)
simple Node
{
parameters:
@display(“i=device/laptop”);
gates:
input in[];
output out[];
}
- Implement Node Behavior (Node.cc)
We will require to execute the behaviour of each node thus that it can forward messages to the accurate destination (either within the star or the ring topology).
Sample Node Behavior (Node.cc)
#include <omnetpp.h>
using namespace omnetpp;
class Node : public cSimpleModule
{
private:
int nodeId;
bool isSwitch; // If the node is a switch in the star topology
bool isRing; // If the node belongs to the ring topology
protected:
virtual void initialize() override;
virtual void handleMessage(cMessage *msg) override;
void forwardToRing(cMessage *msg); // Function to send message to ring
void forwardToStar(cMessage *msg); // Function to send message to star
};
Define_Module(Node);
void Node::initialize()
{
nodeId = getIndex();
isSwitch = (strcmp(getName(), “switch”) == 0);
isRing = (strcmp(getName(), “ringNode1”) == 0 || strcmp(getName(), “ringNode2”) == 0 || strcmp(getName(), “ringNode3”) == 0);
if (isSwitch) {
// Switch initiates communication by sending a message to the star nodes
cMessage *msg = new cMessage(“Message from Switch to Star”);
scheduleAt(simTime() + 1.0, msg); // Send after 1 second
}
}
void Node::handleMessage(cMessage *msg)
{
if (isSwitch) {
// The switch sends messages to star nodes
forwardToStar(msg);
} else if (isRing) {
// Ring nodes forward messages within the ring
forwardToRing(msg);
} else {
// Star nodes forward messages to the switch or respond
EV << “Node ” << getName() << ” received: ” << msg->getName() << ” and responding.\n”;
cMessage *response = new cMessage(“Response to Switch”);
send(response, “out”, 0); // Send response back to the switch
delete msg;
}
}
void Node::forwardToStar(cMessage *msg)
{
// Forward the message to all connected star nodes
for (int i = 0; i < gateSize(“out”); i++) {
cMessage *dupMsg = msg->dup(); // Duplicate message for each node
EV << “Switch sending message to Star Node ” << i << “.\n”;
send(dupMsg, “out”, i); // Forward to star nodes
}
delete msg;
}
void Node::forwardToRing(cMessage *msg)
{
// Forward the message to the next ring node
EV << “Ring node forwarding message to the next node in the ring.\n”;
send(msg, “out”, 0); // Forward within the ring
}
- Run the Simulation
To run the simulation, describe the network parameters and behaviour in the omnetpp.ini configuration file.
Sample OMNeT++ Configuration (omnetpp.ini)
[General]
network = HybridTopology
sim-time-limit = 10s
# Node-specific configurations
*.switch.numGates = 4 # Switch connects to 4 star nodes
*.ringNode*.numGates = 1 # Each ring node has one gate to connect to the next node in the ring
*.starNode*.numGates = 1 # Star nodes have one gate to connect to the switch
- Visualize and Analyze
- Message Flow: We will observe messages originating from the switch (central hub in the star topology) and propagating via both the star and ring sections of the hybrid network.
- Performance Metrics: We can be monitored message latency, throughput, and investigate how messages travel via the network from the star section to the ring section and vice versa.
- Enhance the Simulation
Here are a few ideas to prolong the simulation:
- Bi-directional Communication: Permit bidirectional communication among the star and ring topologies.
- Load Balancing: Execute load-balancing algorithms on the switch or ring nodes to distribute traffic more effectively.
- Error Detection: Launch an error detection mechanisms in the ring nodes to mimic failure recovery.
- Multi-level Hybrid Topology: We can prolong it by aggregating more topologies (like bus or mesh) into the network to replicate complex hybrid networks frequently discovered in real-world scenarios.
Example of Fault Tolerance in Hybrid Topology
We could execute the fault tolerance in the ring topology by verifying if a message attains a faulty node and then rerouting the message to a backup node.
void Node::handleMessage(cMessage *msg)
{
if (isRing) {
// Check for node failure
if (isNodeFaulty()) {
EV << “Node ” << getName() << ” is faulty, rerouting message.\n”;
forwardToBackup(msg); // Reroute message to backup node
} else {
forwardToRing(msg); // Forward normally
}
} else {
// Handle normal forwarding logic
…
}
}
Utilising the above sequential procedure that contains significant concepts with examples are supports you to simulate the Hybrid Topology projects within OMNeT++ tool. Likewise, we will deliver various approach to this projects if necessary. To get the best service, shoot us an email at phdprime.com with your details, and we’ll provide top-notch simulation services. If you’re looking to simulate Hybrid Topology Projects using the OMNeT++ tool, we’ve got everything you need to make sure your project is completed on time. Let us handle your comparison analysis, customized just for you. We also specialize in various network topologies like Bus, Star, Ring, and Mesh for your projects.
