How to Start Circular Topology Projects Using OMNeT++

To stimulate a Circular Topology Simulation in OMNeT++ has been includes their connecting a nodes in a loop in which the every node is linked to two other nodes, forming a closed circular network. This topology is frequently used in token-based systems or for redundancy in networking.

Here’s a step-by-step guide to start a Circular Topology Project in OMNeT++:

Steps to Start Circular Topology Projects Using OMNeT++

  1. Understand Circular Topology
  • Definition: A circular topology considers as the ring topology it connects the every node to two adjacent nodes, forming a closed-loop structure.
  • Characteristics:
    • Data flows either in one direction such as unidirectional or both directions bidirectional.
    • It provides the redundancy in bidirectional settings.
    • A failure in unidirectional setting can disrupt the whole network unless mitigated.
  • Applications:
    • It includes the Token-passing networks such as Token Ring.
    • The system is redundant.
    • Fibre optic networks
  1. Set Up OMNeT++ and INET Framework
  • Install OMNeT++: Download and set up OMNeT++ from the official website.
  • Install INET Framework:
    • INET offers the modules for wired and wireless communication.
  1. Define Project Scope

Step 3.1: Goals

  • Replicate the data flow in a circular topology in which the packets traverse with several nodes.
  • Estimate the parameter metrics such as:
    • Packet delivery ratio (PDR).
    • Latency.
    • Throughput.

Step 3.2: Metrics

  • Packet Delivery Ratio (PDR): Rate for successfully delivered in the packets.
  • Latency: Take the normal time for packets we traverse the network.
  • Throughput: Number of data throughput is transferred with the network.
  1. Design the Circular Topology

Describe the network in which nodes are linked in a circular structure.

Example .ned File:

network CircularTopology {

submodules:

node[6]: StandardHost;  // Nodes in the circular topology

connections allowunconnected:

node[0].ethg++ <–> EthernetLink <–> node[1].ethg++;

node[1].ethg++ <–> EthernetLink <–> node[2].ethg++;

node[2].ethg++ <–> EthernetLink <–> node[3].ethg++;

node[3].ethg++ <–> EthernetLink <–> node[4].ethg++;

node[4].ethg++ <–> EthernetLink <–> node[5].ethg++;

node[5].ethg++ <–> EthernetLink <–> node[0].ethg++;  // Close the loop

}

  1. Configure Node Behavior

Step 5.1: Data Transmission

Use INET’s UdpBasicApp to simulate traffic between nodes.

Example .ini File Configuration:

[Config CircularTopologySimulation]

network = CircularTopology

# Traffic configuration for node[0] (source)

**.node[0].numApps = 1

**.node[0].app[0].typename = “UdpBasicApp”

**.node[0].app[0].destAddress = “node[3]”

**.node[0].app[0].startTime = 1s

**.node[0].app[0].sendInterval = uniform(1s, 2s)

**.node[0].app[0].packetLength = 512B

# Traffic configuration for node[3] (destination)

**.node[3].numApps = 1

**.node[3].app[0].typename = “UdpSink”

# Additional traffic configuration for other nodes

**.node[2].numApps = 1

**.node[2].app[0].typename = “UdpBasicApp”

**.node[2].app[0].destAddress = “node[5]”

**.node[2].app[0].startTime = 2s

**.node[2].app[0].sendInterval = uniform(2s, 4s)

**.node[2].app[0].packetLength = 512B

**.node[5].numApps = 1

**.node[5].app[0].typename = “UdpSink”

# Simulation time

sim-time-limit = 50s

  1. Run and Visualize the Simulation
  • Run the Simulation: Introduce the replication for the process of OMNeT++.
  • Monitor Behavior:
    • Follow the data flowing with the circular network for behaviour.
    • Monitor the parameter metrics such as latency and packet delivery ratio.
  1. Analyze Results

Metrics to Evaluate:

  1. Packet Delivery Ratio (PDR):
    • Calculate the rate of packets delivered successfully with the circular topology in a PDR.
  2. Latency:
    • Measure the latency established through traversing several nodes.
  3. Throughput:
    • Study the throughput in data transfer rate with the network .

Visualization:

  • Used envision for OMNeT++’s tools we visualize the packet flows and node interactions.
  1. Enhance the Project

Step 8.1: Bidirectional Circular Topology

  • Enhance the connection in the different direction for redundancy and rapid communication.

Example Bidirectional Connections:

connections allowunconnected:

node[0].ethg++ <–> EthernetLink <–> node[1].ethg++;

node[1].ethg++ <–> EthernetLink <–> node[2].ethg++;

node[2].ethg++ <–> EthernetLink <–> node[3].ethg++;

node[3].ethg++ <–> EthernetLink <–> node[4].ethg++;

node[4].ethg++ <–> EthernetLink <–> node[5].ethg++;

node[5].ethg++ <–> EthernetLink <–> node[0].ethg++;

node[1].ethg++ <–> EthernetLink <–> node[0].ethg++;

node[2].ethg++ <–> EthernetLink <–> node[1].ethg++;

node[3].ethg++ <–> EthernetLink <–> node[2].ethg++;

node[4].ethg++ <–> EthernetLink <–> node[3].ethg++;

node[5].ethg++ <–> EthernetLink <–> node[4].ethg++;

node[0].ethg++ <–> EthernetLink <–> node[5].ethg++;

Step 8.2: Simulate Faults

  • Establish the node or connection failures and follow on the effect for the network. Step 8.3: Add Dynamic Routing
  • Used the dynamic routing protocols such as AODV, OSPF we adjust the variations in the network.

Step 8.4: Scale the Network

  • Improve the number of nodes and we replicate the larger circular topologies.

Step 8.5: Wireless Circular Topology

  • Used the topology for INET’s wireless components we replicate the circular topology deprived of physical connection.
  1. Example Output
  • Before Enhancements:
    • Data flows are smoothly in single direction.
    • Delay and throughput are fixed below the general environments.
    • After Enhancements:
    • Bidirectional connection decreases the delay and enhances the fault tolerance.
    • Routing protocols are dynamically adjusted their node or connection failures.

Would you like help implementing specific features like fault tolerance, wireless communication, or dynamic routing in the circular topology?

By OMNeT++ tool, we demonstrated the fundamental method with the sample coding for Circular Topology project that were simulated and visualized the outcomes. Additional queries regarding this project will be addressed in another document.