How to Start Hybrid Topology Projects Using OMNeT++

To start a Hybrid Topology project using OMNeT++ which needs to integrate the modules from various kinds of network topologies like star, mesh, or bus, for making a hybrid network, which is more adaptable and suitable for complex scenarios.

For example, a Hybrid Topology might be utilised a star topology for interaction with a central node and mesh topology for interaction among the other nodes. This type of topology is frequently utilised for real-world networks, which integrate centralized control including decentralized communication.

Following is a comprehensive technique to get started with making a Hybrid Topology project in OMNeT++:

Steps to Start Hybrid Topology Projects in OMNeT++

Step 1: Install OMNeT++ and INET Framework

Initially we make sure that OMNeT++ and the INET framework are installed correctly, before executing the Hybrid Topology simulation.

  1. Install OMNeT++:
    • We shall download the new version of OMNeT++ and we adhere to the installation instruction based on the OS like Windows, Linux, or macOS.
  2. Install INET Framework:
    • We can download the INET Framework using INET GitHub repository.
    • Adhere to the provided guidance for incorporating INET with OMNeT++.

Step 2: Create a New OMNeT++ Project

  1. Go to OMNeT++ IDE.
  2. Make a New Project:
    • By navigating File → New → OMNeT++ Project.
    • Name it to the project as HybridTopologySimulation and then choose the position of the project.

Step 3: Define the Hybrid Topology

Network topology is created to utilise NED files in OMNeT++. For a Hybrid Topology, we need to integrate several sub-topologies like star and mesh for making a custom network.

Example: Hybrid Topology with Star + Mesh Components

Now, we make a hybrid topology in which:

  • One central node (star topology) links to numerous nodes.
  • These nodes contain direct interaction links among them (mesh topology).
  1. Make a hybrid network structure using .ned file as HybridTopology.ned:

network HybridTopology

{

parameters:

int numNodes = 4;  // Number of nodes in the network

int centralNode = 1; // Index of central node

submodules:

// Central node (hub)

centralNode: Node;

// Peripheral nodes (leaf nodes)

nodes[par(numNodes-1): Node];

connections:

// Connect all peripheral nodes to the central node (star topology)

for i = 0..numNodes-2 {

nodes[i].ethg++ <–> EtherInterface <–> centralNode.ethg++;

}

// Connect peripheral nodes to each other (mesh topology)

for i = 0..numNodes-2 {

for j = i+1..numNodes-2 {

nodes[i].ethg++ <–> EtherInterface <–> nodes[j].ethg++;

}

}

}

Explanation:

  • centralNode: In the network, this denotes the central node (typically the hub within a star topology).
  • nodes: A peripheral nodes array, which associates to the central node and also to each other, to make the mesh topology.
  • Connections:
    • Initially, link every peripheral node to the central node that making the star topology.
    • Then, associate the peripheral nodes to each other which are creating a mesh topology.

Step 4: Define the Node Module

Now, we will need to specify the each node behavior within the network. In this example, we make a simple Node module, which each device will be utilised.

  1. Make a .ned file like Node.ned for the node module:

module Node

{

parameters:

@display(“i=block/server”);

submodules:

ethg: EtherHost;  // Ethernet interface for communication

connections:

ethg++ <–> EtherInterface <–> ethg++;

}

Explanation:

  • EtherHost: It specifies the network interface for every node.
  • EtherInterface: Mimics the physical interface of the network via which nodes interact.

Step 5: Configure Simulation Parameters

Set the simulation settings using omnetpp.ini file. This file will be indicate diverse metrics like simulation time, the volume of nodes, and the type of traffic to make.

  1. Create or edit omnetpp.ini:

network = HybridTopology   # Specify the NED file to use

# Simulation settings

sim-time-limit = 100s      # Total simulation time

*.numNodes = 4             # Number of peripheral nodes

*.centralNode = 1          # The central node in the topology

# Define application behavior for the nodes

*.nodes[*].app.packetRate = 100pkts/s   # Packet rate for the nodes

Explanation:

  • network: It indicates which network model using in the .ned file.
  • sim-time-limit: Describes the total time for the replication.
  • *.numNodes: It manages the volume of peripheral nodes within the network.
  • *.centralNode: Configures the central node’s index.
  • app.packetRate: Describes the packet generation rate for the nodes.

Step 6: Build and Run the Simulation

  1. Build the Project:
    • Right-click on the project and then click Build Project. It will be compiled the network set up and any component we have made.
  2. Run the Simulation:
    • When the build execution is accomplish then we select the Run button within OMNeT++. It will be executed the simulation.
  3. Visualize the Simulation:
    • OMNeT++ environment offers a GUI in which we can envision the network behavior, monitor the packet transmission, and then observe the performance parameters like latency, throughput, and packet loss.

Step 7: Enhance the Hybrid Topology

When executing the simple hybrid topology then ewe can prolong it within numerous ways according to the simulation targets.

  1. Routing Protocols:
  • Integrate the routing protocols for mesh nodes like AODV, OLSR, or RIP, to allow interaction among the mesh-connected nodes and to enhance traffic flow.
  1. Traffic Models:
  • Launch various traffic generation models like TCP or UDP for all nodes. It will support to replicate the real-time scenarios in which nodes transmit the packets including various features.
  1. Mobility:
  • We need to design the mobile nodes in the mesh or peripheral nodes. Mobility models such as Random Walk or Gauss-Markov can be utilised for replicating dynamic modifications within the network topology.
  1. Security Attacks:
  • Mimic security attacks like DoS, MITM, or routing attacks for examining how the hybrid topology executes in critical conditions.
  1. Error Handling:
  • Launch node failures or link failures for analysing the hybrid topology’s resilience and observe how the network manages the failures that particularly in the portion of the mesh topology.

Step 8: Analyze the Results

We will want to examine the outcomes to utilise OMNeT++’s built-in tools after execution the simulation for analysis. These tools permit us:

  • To estimate the performance parameters such as packet delay, throughput, packet loss, and so on.
  • Observing network behavior and monitor how successfully the network retrieves from failures.
  • Analyse packet-level interaction to utilise Wireshark (if we are configured packet capture).

Through this procedure, we can get more knowledge about how to set up and replicate the Hybrid Topology Projects using OMNeT++. We can also offer additional information to extend it further according to the certain use case.