To simulate an Overlay Topology in OMNeT++ has needs to generate a virtual network that performs on top of a physical network. In an overlay topology, nodes form logical connections on top of a base network that cannot correspond directly to the physical connections. This kind of topology is usual in peer-to-peer (P2P) networks, content delivery networks (CDNs), and virtual private networks (VPNs), in which nodes in the overlay form a virtual network for certain communication tasks while depend on the primary physical organization for actual data transmission. Send all your details to phdprime.com we will aid you with best simulation guidance for your projects.
Here’s a step-by-step guide to simulating an Overlay Topology in OMNeT++ using the INET framework:
Steps to Simulate Overlay Topology in OMNeT++
- Install OMNeT++ and INET Framework:
Make sure that we have OMNeT++ and the INET framework installed, by way of the INET framework deliver the essential tools and modules for network simulation, has P2P overlays, routing protocols, and virtual layers.
- Download and install OMNeT++.
- Download and install the INET Framework.
- Define the Physical Network Topology in NED File:
The physical network is the primary infrastructure upon which the overlay will operate. Here’s an instance NED file for a simple physical network of interconnected nodes:
network PhysicalNetwork
{
parameters:
int numNodes = default(5); // Number of physical nodes
submodules:
// Define the physical network nodes
node[numNodes]: <NodeType> {
@display(“p=100+200*i,100”);
}
connections allowunconnected:
// Connect all nodes in a basic physical network (fully connected or a mesh)
for i=0..numNodes-2 {
for j=i+1..numNodes-1 {
node[i].ethg++ <–> Eth100M <–> node[j].ethg++;
}
}
}
In this example:
- numNodes defines the number of physical nodes.
- The node[numNodes] array signifies the physical nodes.
- Eth100M signifies a 100 Mbps Ethernet link among the nodes, forming a basic physical network.
- Define Overlay Topology in NED:
An overlay topology is a logical network generated on top of the physical network. Overlay nodes have virtual links that do not correspond directly to the physical connections. Below is an instance of how to describe an overlay network:
network OverlayNetwork extends PhysicalNetwork
{
submodules:
// Define overlay network nodes as a subset of physical network nodes or new virtual nodes
overlayNode[5]: <OverlayNodeType> {
@display(“p=100+200*i,300”);
}
connections:
// Logical connections between overlay nodes (may not correspond to physical links)
overlayNode[0].overlayg++ <–> OverlayLink <–> overlayNode[1].overlayg++;
overlayNode[1].overlayg++ <–> OverlayLink <–> overlayNode[2].overlayg++;
overlayNode[2].overlayg++ <–> OverlayLink <–> overlayNode[3].overlayg++;
overlayNode[3].overlayg++ <–> OverlayLink <–> overlayNode[4].overlayg++;
// Additional logical overlay connections as needed
}
In this example:
- overlayNode[5] describes the overlay nodes that form the virtual network.
- OverlayLink signify a virtual link among nodes in the overlay.
- The overlayg++ gate is utilized to handle connections in the overlay network.
- Define Node Types for the Physical and Overlay Networks:
We need to utilize INET’s StandardHost for both the physical and overlay nodes, or describe custom node types.
Here’s an example for defining node types:
import inet.node.inet.StandardHost;
module PhysicalNodeType extends StandardHost
{
parameters:
@display(“i=device/router”); // Use router icon for physical nodes
}
module OverlayNodeType extends StandardHost
{
parameters:
@display(“i=device/laptop”); // Use laptop icon for overlay nodes
gates:
input overlayg; // Gate for overlay traffic
output overlayg;
}
Here, PhysicalNodeType describes the physical layer node by the way of a router, since OverlayNodeType signifies a virtual overlay node that interacts through an overlay link.
- Configure the INI File:
In the omnetpp.ini file, setup simulation parameters like traffic patterns, IP addressing, and overlay behaviour.
Here’s an instance INI file for setting up communication in the overlay network:
network = OverlayNetwork
sim-time-limit = 50s # Set simulation time
# Configure IP addresses for the physical and overlay nodes
*.node[*].networkLayer.ipv4.address = “10.0.0.x” # Physical network IPs
*.overlayNode[*].networkLayer.ipv4.address = “192.168.0.x” # Overlay network IPs
# Configure TCP traffic between overlay nodes
*.overlayNode[0].numApps = 1
*.overlayNode[4].numApps = 1
# Define a TCP client on overlayNode[0] and a TCP server on overlayNode[4]
*.overlayNode[0].app[0].typename = “TcpBasicClientApp”
*.overlayNode[0].app[0].connectAddress = “192.168.0.4” # IP of the destination overlay node
*.overlayNode[0].app[0].startTime = 2s
*.overlayNode[0].app[0].stopTime = 48s
*.overlayNode[4].app[0].typename = “TcpBasicServerApp” # TCP server on overlayNode[4]
In this configuration:
- IP addresses are assigned isolated for physical and overlay nodes.
- TCP traffic is created among two overlay nodes (overlayNode[0] and overlayNode[4]).
- Simulate Traffic Using TCP or UDP:
We need to replicate traffic over the overlay network using either TCP or UDP. Here’s an instance of configuring UDP traffic in the overlay network:
# Configuring UDP traffic from overlayNode[0] to overlayNode[4]
*.overlayNode[0].app[0].typename = “UdpBasicApp”
*.overlayNode[0].app[0].destAddresses = “192.168.0.4” # IP address of overlayNode[4]
*.overlayNode[0].app[0].destPort = 5000
*.overlayNode[0].app[0].packetLength = 1024B
*.overlayNode[0].app[0].sendInterval = uniform(1s, 2s)
*.overlayNode[0].app[0].startTime = 2s
*.overlayNode[0].app[0].stopTime = 48s
# Configure overlayNode[4] as a UDP sink
*.overlayNode[4].app[0].typename = “UdpSink”
*.overlayNode[4].app[0].localPort = 5000
This configuration creates an UDP traffic from overlayNode[0] to overlayNode[4] in the overlay network.
- Run the Simulation:
- Open OMNeT++ IDE, compile the project, and execute the simulation.
- Utilize Qtenv to envision both the physical and overlay networks and track packet transmissions.
During the simulation, traffic will flow logically among overlay nodes that are mapped onto physical nodes.
- Analyse the Results:
OMNeT++ deliver detailed logs and statistics to measure network performance. We need to observe:
- Throughput: Assess the data flow among overlay nodes.
- Latency: Evaluate the latency in sending packets among overlay nodes.
- Packet Loss: Monitor lost packets within the overlay network.
We need to utilize Plove or Scave to plot graphs and measure the data collected in the period of the simulation.
- Advanced Features (Optional):
- Routing in the Overlay: Execute routing algorithms (e.g., DHT-based routing) in the overlay network to handle packet forwarding among overlay nodes.
- Mobility Models: incorporate mobility to overlay nodes if we are replicating mobile overlay networks (e.g., MANETs).
- Security in Overlays: Apply an encryption or tunnelling protocols to replicate secure overlay networks like VPNs.
- Multi-Layer Protocols: Utilize multi-layer communication in which overlay packets are encapsulated in the physical network packets.
Example of Adding Overlay Routing:
# Enable OLSR routing for overlay nodes
*.overlayNode[*].hasNetworkLayer = true
*.overlayNode[*].ipv4.routingProtocol = “Olsr”
*.overlayNode[*].olsr.interfaceTableModule = “^.interfaceTable”
*.overlayNode[*].olsr.routingTableModule = “^.routingTable”
This allows OLSR routing within the overlay network, enabling nodes to enthusiastically route packets.
Summary:
- Define Physical and Overlay Topologies: Utilize NED to describe both the physical network and the overlay network.
- Node Configuration: Describe separate node types for physical and overlay layers.
- Traffic Simulation: Replicate communication among overlay nodes using TCP or UDP.
- Run and Analyse: Execute the simulation and utilize OMNeT++ tools to evaluate throughput, latency, and packet loss.
From this demonstration, we deliver the basic process for Overlay Topology project that includes installation procedure, analyse and envision the results using OMNeT++ analysis tool. Further specific details will be added later.
