How to Start Grid Topology Projects Using OMNeT++

To start a Grid Topology project using OMNeT++, we will need to configure a network in which nodes are organized within in a grid-like structure. In this kind of topology, nodes are associated to its neighbouring nodes in horizontal and vertical directions for making a mesh of connections. Grid topology is helpful to replicate the networks such as wireless mesh networks, smart grids, or sensor networks.

Below is a comprehensive method to making a Grid Topology in OMNeT++:

Steps to Start Grid Topology Projects in OMNeT++

Step 1: Install OMNeT++ and INET Framework

Make sure that both OMNeT++ and the INET Framework are installed before executing the grid topology:

  1. Install OMNeT++:
    • We should download the new version of OMNeT++ on the system and we adhere to the installation guidance.
  2. Install INET Framework:
    • We can download the INET Framework using INET GitHub repository and follow the provided installation instructions.

Step 2: Create a New OMNeT++ Project

  1. Go to OMNeT++ IDE.
  2. Make a New OMNeT++ Project:
    • By navigating File → New → OMNeT++ Project.
    • Name it to the project as GridTopology and choose the project location to save it.

Step 3: Define the Grid Topology

Nodes are organized within a 2D grid, and every single node normally contains neighbors to the left, right, top, and bottom excepting the nodes at the borders or corners in a Grid Topology.

Example: Grid Topology with 3×3 Nodes

We need to make a 3×3 grid topology that has 9 nodes are organized within 3 rows and 3 columns.

  1. Make the network topology using .ned file as GridTopology.ned:

network GridTopology

{

parameters:

int numRows = 3;  // Number of rows in the grid

int numCols = 3;  // Number of columns in the grid

submodules:

nodes[numRows * numCols: Node];  // Array of nodes, total = rows * cols

connections:

// Loop through rows and columns to create grid connections

// Create connections between adjacent nodes horizontally (left-right)

for i=0..(numRows-1) {

for j=0..(numCols-2) {

nodes[i*numCols + j].ethg++ <–> EtherInterface <–> nodes[i*numCols + j + 1].ethg++;

}

}

// Create connections between adjacent nodes vertically (top-bottom)

for i=0..(numRows-2) {

for j=0..(numCols-1) {

nodes[i*numCols + j].ethg++ <–> EtherInterface <–> nodes[(i+1)*numCols + j].ethg++;

}

}

}

Explanation:

  • numRows: Specifies the volume of rows within the grid.
  • numCols: In the grid, describes the amount of columns.
  • nodes: An array to signify the total nodes which are computed like numRows * numCols.
  • connections: This segment describes the connections among the nodes.
    • The initial nested loop makes horizontal connections (left-right) for every row.
    • The second nested loop generates vertical connections (top-bottom) for each column.

This configuration will be made a 2D grid in which nodes are linked within horizontal and vertical directions; however the nodes at the borders like first and last rows, first and last columns will only need 2 neighbors.

Step 4: Define the Node Module

Now, we want to describe the node module for every node. In this example, from the INET framework we require utilise EtherHost module that replicates a basic Ethernet host for every node.

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

module Node

{

parameters:

@display(“i=block/server”);  // Display properties for visualization

submodules:

ethg: EtherHost;  // Ethernet host module for network communication

connections:

ethg++ <–> EtherInterface <–> ethg++;  // Ethernet interface connection

}

Explanation:

  • EtherHost: It denotes a network node, which can transmit and inherit the Ethernet packets.
  • EtherInterface: Offers the interaction interface for every single node.

It will need to describe the each node’s behaviour within the grid since an Ethernet host, which interacts with their nearby nodes.

Step 5: Configure Simulation Parameters

When the grid topology and node components are describing then set the simulation metrics using omnetpp.ini file. This file has simulation-specific settings like volume of nodes, traffic generation metrics, and simulation time.

  1. Create or edit the omnetpp.ini file:

network = GridTopology    # Name of the network model

# Simulation settings

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

*.numRows = 3                # Number of rows in the grid

*.numCols = 3                # Number of columns in the grid

# Packet generation configuration for each node

*.nodes[*].app.packetRate = 100pkts/s   # Example packet rate for each node

Explanation:

  • network: Indicates the network model utilising defined in the .ned file.
  • sim-time-limit: Describes the total simulation time.
  • numRows and numCols: It denotes the grid dimensions.
  • packetRate: It shows the packet generation rate for every node. Modify the value, if required.

Step 6: Build and Run the Simulation

  1. Build the Project:
    • In OMNeT++ IDE, right-click on the project and choose Build Project for compiling the .ned files and other essential modules.
  2. Run the Simulation:
    • When the project is constructing then we select the Run button to execute the simulation.
  3. Visualize the Simulation:
    • OMNeT++ offers a GUI, which permits for envisioning the network. The grid of nodes will show like a 2D array, and we will be capable of observe the packets to be swapped among them.

Step 7: Enhance the Grid Topology

When basic simulation functioning then we need to improve the grid topology including diverse aspects:

  1. Traffic Models:
  • Integrate the traffic models like TCP or UDP for replicating the packet exchange among certain nodes or over the complete grid.
  • We can make traffic patterns among the nearby nodes or arbitrarily among any nodes within the grid.
  1. Routing Protocols:
  • Execute the routing protocols like RIP, OSPF, or AODV for wireless grids to learn the influence of routing within grid-like topologies.
  1. Mobility:
  • If we will replicate the mobile networks then launch mobility models such as Random Waypoint or Gauss-Markov for replicating the movement of nodes in the grid.
  1. Node Failures and Fault Tolerance:
  • Launch the node or link failures to measure how the network replies when a node or connection drops.
  • We execute the fault tolerance policies to make sure that the network can even operate in spite of failures.
  1. Quality of Service (QoS):
  • Execute and estimate the QoS metrics such as latency, throughput, and packet loss in diverse traffic patterns and network sets up.
  1. Security Simulations:
  • Launch security attacks like Denial of Service (DoS) or packet sniffing for examining how the grid network performs in attack.

Step 8: Analyze the Results

When the simulation is executing then we can estimate the key performance indicators (KPIs) to utilise OMNeT++’s analysis tools:

  • Throughput: Measure the total volume of data that are effectively sent through the grid.
  • Latency: Compute the delay from source to destination nodes within packet transmission.
  • Packet Loss: Estimate the volume of packets which are dropped in the course of transmission.
  • Routing Performance: Calculate the routing protocols effectiveness (if used) within determining the best routes.

Analyse the packet-level details and collect insights to the performance of network to utilise Wireshark or OMNeT++’s built-in analysis tools.

Conclusion

In OMNeT++, making a Grid Topology:

  1. Create the network topology to utilise nested loops for associating nodes horizontally and vertically within a .ned file.
  2. Make node modules for estimating network interaction with the support of EtherHost.
  3. Set the simulation metrics to configure traffic patterns, simulation time, and other settings using omnetpp.ini configuration files.
  4. Compile and execute the simulation for envisioning the grid topology and monitoring the behaviour of network.
  5. Improve the network topology including routing protocols, QoS, mobility models, and security simulations.
  6. Finally, examine the simulation outcomes for estimating network’s performance and robustness.

With the help of OMNeT++ environment, we had presented the detailed simulation steps and sample coding for creating and testing the Grid Topology. If required, we will resolve the other queries through another manual.