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How to Implement Extended Star Topology in OMNeT++

To implement an extended star topology in OMNeT++ requires a network that has multiple star topologies are linked to one another by creating it. It includes the benefits of the star topology includes simplicity and ease of troubleshoot as well as the greater scalability of interrelating many star networks.

We offered the approach on how to implement an extended star topology in OMNeT++ using the INET framework:

Step-by-Step Implementation:

  1. Set Up OMNeT++ and INET Framework
  • Make sure OMNeT++ and the INET framework is properly installed and configured. To simulate different network topologies like star and extended star networks, we can use the necessary modules provided by the INET framework.
  1. Define the Extended Star Topology in a NED File
  • State the network topology by creating a .ned file. Numerous star networks are linked to a central node (like a router or switch) in an extended star topology.

Example:

package extendedStarTopologyExample;

import inet.node.inet.StandardHost;

import inet.node.inet.Router;

network ExtendedStarTopology

{

parameters:

int numClusters = default(3);  // Number of star networks (clusters)

int numNodesPerCluster = default(4);  // Number of nodes per star network

submodules:

centralNode: Router {

parameters:

@display(“p=400,300”);

}

cluster[numClusters]: Router {

parameters:

@display(“p=200+400*cos(pi/2+i*2*pi/numClusters),200+300*sin(pi/2+i*2*pi/numClusters)”);

}

node[numClusters][numNodesPerCluster]: StandardHost {

parameters:

@display(“p=200+200*cos(pi/2+j*2*pi/numNodesPerCluster)+200*cos(pi/2+i*2*pi/numClusters),300+200*sin(pi/2+j*2*pi/numNodesPerCluster)+300*sin(pi/2+i*2*pi/numClusters)”);

}

connections allowunconnected:

for i=0..numClusters-1 {

centralNode.ethg++ <–> Eth10G <–> cluster[i].ethg++;

for j=0..numNodesPerCluster-1 {

cluster[i].ethg++ <–> Eth10G <–> node[i][j].ethg++;

}

}

}

  • In this instance:
    • Router is used as the central node (centralNode) and as the hubs for each star network (cluster).
    • In every star network, StandardHost signifies a single node.
    • Use the Eth10G connections to link the central node to each cluster and to connect the nodes within each star to their corresponding cluster hub.
  1. Configure the Nodes in OMNeT++ INI File
  • In the omnetpp.ini file, configure the properties of the nodes like IP addresses and the applications they will run.

Example:

network = extendedStarTopologyExample.ExtendedStarTopology

# Configure IP addresses and routing

*.centralNode.ipv4.arp.typename = “GlobalArp”

*.cluster[*].ipv4.arp.typename = “GlobalArp”

*.node[*][*].ipv4.arp.typename = “GlobalArp”

*.node[*][*].ppp[0].ipv4.address = “10.0.0.x”

*.node[*][*].ppp[0].ipv4.netmask = “255.255.255.0”

# Example application setup: node[0][0] in the first cluster sends data to node[2][0] in another cluster

*.node[0][0].numApps = 1

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

*.node[0][0].app[0].destAddresses = “10.0.0.2”  # IP address of node[2][0]

*.node[0][0].app[0].destPort = 5000

*.node[0][0].app[0].messageLength = 1024B

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

*.node[2][0].numApps = 1

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

*.node[2][0].app[0].localPort = 5000

  • In this sample:
    • node[0][0], which belongs to the first star network (cluster), is configured to send UDP packets to node[2][0], which belongs to another star network.
    • node[2][0] is configured to receive and process the packets.
  1. Configure Routing Protocols
  • We might need to generate routing protocols to handle how data is forwarded over the network based on the difficulty of the extended star topology. For instance, we can enable OSPF (Open Shortest Path First) or another suitable protocol.

Instance:

*.centralNode.hasOspf = true

*.cluster[*].hasOspf = true

*.node[*][*].hasOspf = true

  • This configuration enables OSPF on all routers and nodes permitting dynamic routing through the extended star network.
  1. Run the Simulation
  • After setting up the network topology and configuration, compile and run the simulation in OMNeT++. We could see the central node joining multiple star networks, with data being routed amongst various nodes over the clusters.
  1. Analyze the Results
  • Visualize and analyze the network traffic using OMNeT++’s built-in tools. Examine how data flows among the various star networks, how the central node handles the traffic, and the overall performance of the extended star topology.
  1. Enhancements and Variations
  • Traffic Analysis: Based on throughput, latency and load balancing through various traffic conditions, we have to evaluate the performance of the network.
  • Fault Tolerance: Simulate the failure of one or more links or nodes and monitor how the network reroutes traffic and keeps connectivity.
  • Scalability: Experiment with adding more clusters or nodes to see how the extended star topology scales with increasing network size.

Example Files

  1. ExtendedStarTopology.ned: Describe the extended star topology.
  2. omnetpp.ini: Contains configuration settings for the simulation.

From this procedure, we successfully learned the information about how to implement the extended star topologies and how it handles the network traffic using some techniques in the OMNeT++. Whenever, you have doubt about this approach we will clarify it.

Reach out to us for further assistance with your comparison analysis in this field. Our team at omnet-manual.com is ready to provide you with implementation and simulation support for Extended Star Topology using the OMNeT++ tool.

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