How to Implement network line switching in OMNeT++

To implement the network line switching in OMNeT++, we have to simulate a communication system in which the dedicated routes (circuits) are accomplished amongst nodes during communication session. It is usually used in out-dated telephone networks, however we can also be applied in data networks in particular situations.

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We offer the step-by-step guide to implementing network line switching in OMNeT++ with examples:

Step-by-Step Implementation:

Define the Network Topology

Nodes: Detect the nodes in the network that will behave as switches or routers.
Links: State the physical or logical links amongst these nodes.
Traffic: Define the type of traffic that will be switched across the network.

Create OMNeT++ Modules for Switches and Links

Switch Module: This module will handle the setup, management, and teardown of connections.
Link Module: Indicates the physical or logical connection amongst two switches, managing data transmission once a path is established.

Example: Switch Module

simple Switch {

gates:

inout lineIn[4]; // Four bidirectional links for simplicity

parameters:

@display(“i=block/switch”);

}

Example: Link Module

simple Link {

gates:

inout linkIn; // Input from one switch

inout linkOut; // Output to another switch

parameters:

double dataRate @unit(“bps”) = default(1Gbps); // Data rate of the link

}

Implement the Internal Logic of Switches

Path Setup: Execute the logic to accomplish a path among the source and destination nodes.
Data Transmission: Once the path is established, the switches should forward data along the reserved path.
Path Teardown: After communication is complete, the path should be released.

Example: Switch Logic in C++

#include <omnetpp.h>

class Switch : public omnetpp::cSimpleModule {

protected:

virtual void handleMessage(omnetpp::cMessage *msg) override;

virtual void setupPath(int src, int dest); // Example method to set up a path

};

Define_Module(Switch);

void Switch::handleMessage(omnetpp::cMessage *msg) {

// Process incoming messages to establish, forward, or tear down a path

int src = msg->par(“src”);

int dest = msg->par(“dest”);

if (strcmp(msg->getName(), “setup”) == 0) {

// Setup path logic

setupPath(src, dest);

} else {

// Forward data along the established path

int nextHop = … // Determine next hop based on the established path

send(msg, “lineIn”, nextHop);

}

void Switch::setupPath(int src, int dest) {

// Logic to establish a path from src to dest

// This may involve reserving resources on links and setting routing tables

}

Implement the Link Logic

Data Transmission: Simulate the transmission of data packets over the link, containing any delays as per the data rate.
Error Handling: Optionally, simulate link failures or errors and how they are managed.

Example: Link Logic in C++

#include <omnetpp.h>

class Link : public omnetpp::cSimpleModule {

protected:

virtual void handleMessage(omnetpp::cMessage *msg) override;

};

Define_Module(Link);

void Link::handleMessage(omnetpp::cMessage *msg) {

// Simulate data transmission delay

double dataRate = par(“dataRate”).doubleValue();

simtime_t transmissionDelay = msg->getBitLength() / dataRate;

sendDelayed(msg, transmissionDelay, “linkOut”);

}

Integrate the Components in a NED File

State the network topology, linking switches through links.
Specify the source and destination nodes for the communication session.

Example: Network Topology in NED

network LineSwitchedNetwork {

submodules:

switchA: Switch;

switchB: Switch;

switchC: Switch;

switchD: Switch;

linkAB: Link;

linkBC: Link;

linkCD: Link;

connections allowunconnected:

switchA.lineIn[0] –> linkAB.linkIn;

linkAB.linkOut –> switchB.lineIn[0];

switchB.lineIn[1] –> linkBC.linkIn;

linkBC.linkOut –> switchC.lineIn[0];

switchC.lineIn[1] –> linkCD.linkIn;

linkCD.linkOut –> switchD.lineIn[0];

}

Run and Analyze the Simulation

Compile: Make certain that all modules are compiled in OMNeT++.
Execute: Run the simulation to see how the network executes and tears down connections, and how data is transmitted over the established paths.
Analyze: Use OMNeT++ tools to evaluate the performance like connection setup time, transmission delay, and throughput.

Advanced Features

Dynamic Path Setup: Implement more difficult path configuration mechanisms like using signaling protocols to establish paths dynamically based on network conditions.
Multiple Connections: Simulate multiple simultaneous connections and assess the performance impact on the network.
Failure Handling: Execute and examine how the network reacts to link or switch failures as well as redirecting of connections.

Example: Dynamic Path Setup

Signaling Protocol: Execute a signaling protocol like RSVP to dynamically establish paths based on network conditions.
Resource Reservation: Simulate resource reservation along the path, making certain that each link has adequate bandwidth for the connection.

Example: Dynamic Path Setup in C++

void Switch::setupPath(int src, int dest) {

// Example logic for dynamic path setup using a signaling protocol

cMessage *setupMsg = new cMessage(“setup”);

setupMsg->addPar(“src”) = src;

setupMsg->addPar(“dest”) = dest;

// Forward the setup message to the next switch

int nextHop = … // Determine next hop

send(setupMsg, “lineIn”, nextHop);

}

In this manual, we gathered the essential details which will help you to implement the Network Line Switching in OMNeT++ with sample snippets. It includes how to generate a topology and how to set up the modules for switch and link with examples. We were intent to provide the future enhancement techniques into this approach.