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How to Implement Extended Bus Topology in OMNeT++

To implement an Extended Bus Topology in OMNeT++, we need to make a network that contains many bus segmented are connected directly or via repeaters or switches. We have to add more segments to extend the basic bus topology to help us in scaling the network during the management of relatively simple structure.  Here’s a step-by-step instructions to implement the extended bus topology:

Step-by-Step Implementation:

  1. Set Up OMNeT++ and INET Framework
  • Make sure that OMNeT++ and the INET framework are installed and properly configured. The INET framework offers the important modules for simulating multiple network topologies as well as extended bus topologies.
  1. Define the Extended Bus Topology in a NED File
  • Define the network topology by creating a .ned file. The extended bus topology contains multiple bus segments linked by repeaters, switches, or directly.

Sample: An Extended Bus Topology with 2 Bus Segments and a Repeater

package extendedBusTopologyExample;

import inet.node.inet.StandardHost;

import inet.node.ethernet.EtherSwitch;  // Alternatively, use a repeater or hub

network ExtendedBusTopology

{

parameters:

int numSegments = default(2);  // Number of bus segments

int numHostsPerSegment = default(3);  // Number of hosts per bus segment

submodules:

busNode[numSegments][numHostsPerSegment]: StandardHost {

parameters:

@display(“p=100+200*i,200+100*j”);

}

repeater: EtherSwitch {  // Can also be a hub or custom repeater module

parameters:

@display(“p=400,300”);

}

connections allowunconnected:

// Connect hosts within each bus segment

for i=0..numSegments-1 {

for j=0..numHostsPerSegment-2 {

busNode[i][j].ethg++ <–> EtherBus <–> busNode[i][j+1].ethg++;

}

}

// Connect bus segments through the repeater

busNode[0][numHostsPerSegment-1].ethg++ <–> EtherChannel <–> repeater.ethg++;

busNode[1][0].ethg++ <–> EtherChannel <–> repeater.ethg++;

}

  • Bus Segments: Every segment is a traditional bus topology, where hosts are connected in a linear fashion.
  • Repeater/Switch: A central repeater or switch links the bus segments, extending the overall network.
  1. Configure the Nodes in OMNeT++ INI File
  • In the omnetpp.ini file, organize the properties of the nodes like IP addresses, routing, and the applications they will run.

Example:

network = extendedBusTopologyExample.ExtendedBusTopology

# Configure IP addresses for the hosts

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

*.busNode[*][*].eth[0].ipv4.address = “10.0.x.y”

*.busNode[*][*].eth[0].ipv4.netmask = “255.255.255.0”

# Example application setup: busNode[0][0] communicates with busNode[1][2]

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

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

*.busNode[0][0].app[0].destAddresses = “10.0.1.3”  # IP address of busNode[1][2]

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

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

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

*.busNode[1][2].numApps = 1

*.busNode[1][2].app[0].typename = “UdpSink”

*.busNode[1][2].app[0].localPort = 5000

  • IP Addressing: Allocating the IP addresses to all host in the network, certifying that each bus segment has a distinctive subnet if needed.
  • Applications: Across the extended bus topology, we have to simulate a network by configuring the applications on the hosts.
  1. Implement Routing and Switching Logic
  • Routing Protocols: we should configure routing amongst the subnets with the help of dynamic routing protocols like OSPF or static routing, if the extended bus topology spans many subnets.

 Example: Enabling OSPF on all nodes

*.busNode[*][*].hasOspf = true

*.repeater.hasOspf = true

  • Switching Logic: The repeater or switch manages the forwarding of packets between the various bus segments.
  1. Run the Simulation
  • Compile and run the simulation in OMNeT++, after setting up the network topology and configuration,. monitor how traffic flows amongst hosts on various bus segments via the repeater or switch.
  1. Analyze the Results
  • Visualize and analyze the network traffic using OMNeT++’s built-in tools. Examine how data is transferred between hosts on different bus segments, how the repeater/switch handles traffic, and how the extended bus topology performs under different conditions.
  1. Enhancements and Variations
  • Scalability Testing: We need to examine the scalability of the extended bus topology by raising the count of bus segments and hosts. Analyze how the network manages increased traffic and node density.
  • Failure Scenarios: Introduce repeater, switch, or link failures to see how the network acts and how resilient it is to disruptions.
  • Load Balancing: If needed, we have to execute load balancing methods to spread the traffic evenly throughout the bus segments.

Example Files

  1. ExtendedBusTopology.ned: State the extended bus topology.
  2. omnetpp.ini: It has the configuration settings for the simulation.

In this demonstration, we helped you to know more about how to implement the extended bus topology and how to use it in the INET framework and we also have to examine whether it works properly or not in the OMNeT++. Please contact us for further assistance with project ideas and comparative analysis in this field. Additionally, receive implementation and simulation support for Extended Bus Topology in the OMNeT++ tool from the developers at omnet-manual.com.

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