To simulate a Bus Topology using OMNeT++, which contains making a network in which all the devices (nodes) share a general communication medium. In a bus topology, for each node is associated to the similar transmission line, and communication is broadcasted to all nodes, however only the intended receiver processes the message. The following steps is helps you to simulate a bus topology in OMNeT++:
Steps to Simulate Bus Topology Projects in OMNeT++
- Create a Simple Network Topology
In a bus topology, all nodes (hosts) are associated to a single communication channel (the bus). The physical medium can be replicated as a shared link in OMNeT++.
- Define the Network Structure (NED File)
Make a NED file to define the network topology. This file will describe the nodes (e.g., computers or devices) and the shared medium (e.g., an Ethernet bus).
Sample NED File (BusTopology.ned)
network BusTopology
{
submodules:
// Define multiple hosts (nodes) in the network
host[5]: Node {
@display(“p=100,100”);
}
// Define a central bus link for shared communication
busLink: Link {
parameters:
datarate = 10Mbps;
delay = 10us;
}
connections allowunconnected:
// Connect each host to the bus link
host[0].out++ –> busLink.in++;
host[0].in++ <– busLink.out++;
host[1].out++ –> busLink.in++;
host[1].in++ <– busLink.out++;
host[2].out++ –> busLink.in++;
host[2].in++ <– busLink.out++;
host[3].out++ –> busLink.in++;
host[3].in++ <– busLink.out++;
host[4].out++ –> busLink.in++;
host[4].in++ <– busLink.out++;
}
- Create the Node (Host) Module (Node.ned)
Describe the behaviour of each node in the bus topology. It is where nodes are transmit and receive packets over the shared bus.
Sample Node Module (Node.ned)
simple Node
{
parameters:
@display(“i=device/laptop”);
gates:
input in[];
output out[];
}
- Implement Node Behavior (Node.cc)
Each node will transmit and receive messages. When a message is transmitted then it will be broadcasted to all nodes, and only the intended receiver will process the message.
Sample Node Behaviour (Node.cc)
#include <omnetpp.h>
using namespace omnetpp;
class Node : public cSimpleModule
{
protected:
virtual void initialize() override;
virtual void handleMessage(cMessage *msg) override;
void sendMessage(); // Function to send messages on the bus
};
Define_Module(Node);
void Node::initialize()
{
// Schedule a self-message to trigger sending a message
if (getIndex() == 0) {
cMessage *msg = new cMessage(“sendMessage”);
scheduleAt(simTime() + 1.0, msg); // Send after 1 second
}
}
void Node::handleMessage(cMessage *msg)
{
if (msg->isSelfMessage()) {
sendMessage(); // Send a message over the bus
} else {
// Process received message
EV << “Node[” << getIndex() << “] received: ” << msg->getName() << “\n”;
delete msg;
}
}
void Node::sendMessage()
{
// Create a new message and send it on the bus
cMessage *msg = new cMessage(“Hello from Node”);
send(msg, “out”, 0); // Send message out to the shared bus
}
- Run the Simulation
- Make an INI configuration file to identify parameters, like the amount of nodes and the bus link configuration.
- Describe how many nodes are in the network, and what type of messages they will transmit.
Sample OMNeT++ Configuration (omnetpp.ini)
[General]
network = BusTopology
sim-time-limit = 10s
# Network-specific parameters
*.host[*].numGates = 2 # Two gates for each host to connect to the bus
- Analysis of Bus Topology Behavior
- Packet Broadcast: When a node transmits a message then it will be broadcasted to all nodes. We can check it by searching the message transmission logs in the simulation output.
- Performance Metrics: We can estimate the parameters like packet delay, throughput, and message collisions (optional), particularly in the case of several nodes are transmitting messages at the similar time.
- Potential Enhancements
- Collision Detection: Execute logic to replicate collisions when two or more nodes are transmit data at the similar time, same to Ethernet’s CSMA/CD (Carrier Sense Multiple Access/Collision Detection).
- Bus Saturation: We can be replicated network saturation by increasing the traffic on the bus and monitoring the influence on performance.
In this given module, we had concentrated the simulation method on how to execute and simulate the Bus Topology projects using OMNeT++. If you require more facts concerning this process we will explain it based on your requests. phdprime.com will serve as your reliable partner in navigating best simulation and network evaluation outcomes.
