How to Start Tree Topology Projects Using OMNeT++

To start a Tree Topology Simulation using OMNeT++, we will create a hierarchical network in which nodes are organized including a central root node, which are associating to intermediate nodes that link to leaf nodes sequentially. Tree topology is generally utilised within networked systems such as IoT and hierarchical LANs.

We will guide you through these steps to configure and replicate the Tree Topology Project in OMNeT++:

Steps to Start Tree Topology Projects in OMNeT++

  1. Understand Tree Topology
  • Definition: A tree topology is a hierarchical network in which nodes are associated within a parent-child connection.
  • Characteristics:
    • A root node associates to middle nodes.
    • Leaf nodes link to intermediate nodes however it isn’t connect to other leaves.
    • High scalability since it is susceptible to root or intermediate node failure.
  • Applications:
    • Hierarchical communication networks.
    • Data aggregation systems.
    • IoT sensor networks.
  1. Set Up OMNeT++ and INET Framework
  • Install OMNeT++: We can install and download the OMNeT++ on the system.
  • Install INET Framework:
    • INET framework offers modules for wired and wireless interaction.
  1. Define Project Scope

Step 3.1: Goals

  • In a tree topology, replicate the hierarchical data flow.
  • Estimate the performance parameters like:
    • Packet delivery ratio.
    • Throughput.
    • Latency.

Step 3.2: Metrics

  • Packet Delivery Ratio (PDR): Rate of packets that are effectively distributed.
  • Latency: Regular time passing through the network for packets.
  • Throughput: Total data send over the network.
  1. Design the Tree Topology

We create a network topology including nodes that are hierarchically organized within a tree structure.

Example .ned File:

network TreeTopology {

submodules:

root: StandardHost;          // Root node

intermediate[2]: StandardHost; // Intermediate nodes

leaf[4]: StandardHost;       // Leaf nodes

connections allowunconnected:

root.ethg++ <–> EthernetLink <–> intermediate[0].ethg++;

root.ethg++ <–> EthernetLink <–> intermediate[1].ethg++;

intermediate[0].ethg++ <–> EthernetLink <–> leaf[0].ethg++;

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

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

intermediate[1].ethg++ <–> EthernetLink <–> leaf[3].ethg++;

}

  1. Configure Node Behavior

Step 5.1: Data Flow

Replicate the traffic from leaf nodes to the root node to utilise INET’s UdpBasicApp, and it denotes the hierarchical data aggregation.

Example .ini File Configuration:

[Config TreeTopologySimulation]

network = TreeTopology

# Traffic configuration for leaf nodes

**.leaf[0].numApps = 1

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

**.leaf[0].app[0].destAddress = “root”

**.leaf[0].app[0].startTime = uniform(1s, 2s)

**.leaf[0].app[0].sendInterval = uniform(1s, 3s)

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

**.leaf[1].numApps = 1

**.leaf[1].app[0].typename = “UdpBasicApp”

**.leaf[1].app[0].destAddress = “root”

**.leaf[1].app[0].startTime = uniform(2s, 3s)

**.leaf[1].app[0].sendInterval = uniform(2s, 4s)

**.leaf[1].app[0].packetLength = 512B

**.leaf[2].numApps = 1

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

**.leaf[2].app[0].destAddress = “root”

**.leaf[2].app[0].startTime = uniform(1s, 3s)

**.leaf[2].app[0].sendInterval = uniform(1s, 3s)

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

**.leaf[3].numApps = 1

**.leaf[3].app[0].typename = “UdpBasicApp”

**.leaf[3].app[0].destAddress = “root”

**.leaf[3].app[0].startTime = uniform(2s, 4s)

**.leaf[3].app[0].sendInterval = uniform(2s, 4s)

**.leaf[3].app[0].packetLength = 512B

# Root node configuration

**.root.numApps = 1

**.root.app[0].typename = “UdpSink”

# Simulation time

sim-time-limit = 100s

  1. Run and Visualize the Simulation
  • Run the Simulation: Use OMNeT++, we execute the simulation.
  • Monitor Behavior:
    • Packets are transmitted from leaf nodes via middle nodes to the root.
    • Examine the network performance parameters.
  1. Analyze Results

Metrics to Evaluate:

  1. Packet Delivery Ratio (PDR):
    • We need to compute the rate of packets that are effectively sent to the root.
  2. Latency:
    • Estimate the duration for packets to pass through from leaf nodes to the root.
  3. Throughput:
    • Measure the rates of data transfer.

Visualization:

  • Envision traffic flows and node communications to utilise OMNeT++’s built-in tools for visualization.
  1. Enhance the Project

Step 8.1: Wireless Tree Topology

  • Replicate a wireless tree topology to utilise INET’s wireless modules that are typically utilised within IoT networks.

Example Wireless Configuration:

*.leaf[*].wlan.radio.channelNumber = 11

*.leaf[*].wlan.snrThreshold = 10dB

*.leaf[*].wlan.txPower = 20mW

*.leaf[*].mobility.typename = “StationaryMobility”

Step 8.2: Add Fault Tolerance

  • We will need to replicate the intermediate nodes or links failure.
  • Execute the rerouting strategies, making sure data delivery.

Step 8.3: Dynamic Data Aggregation

  • Before sending data to the root, mimic scenarios in which intermediate nodes are combined information from leaves.

Step 8.4: Scale the Topology

  • Integrate additional nodes for making a larger tree network including several levels.

Step 8.5: Add Mobility

  • Replicate the dynamic movement of leaf nodes to utilise mobility models of INET framework.
  1. Example Output
  • Before Enhancements:
    • Through intermediate nodes, data floods from leaf nodes to the root.
  • After Enhancements:
    • Dynamic routing adjusts to the node failures or mobility after improvements.
    • Fault tolerance approaches enhance the data delivery.

We had explained the core approach, supported by sample coding for Tree Topology projects that was simulated and analysed with OMNeT++ tool and more information about wireless communication, fault tolerance, or dynamic routing within the tree topology will be provided.