How to start Network-on-Chip Topology Projects Using OMNeT++

To stimulate a Network-on-Chip (NoC) topology project in OMNeT++ has includes the design for communication among cores or nodes in a chip, often in an optimized grid or mesh topology. NoC is generally used for multi-core systems and integrates the high-speed, low-latency communication in a chip. OMNeT++ offers the flexibility in modeling like as complex topologies, nevertheless we want to describe the physical structure for sample mesh, ring and the communication protocols for instance packet switching, routing.

Here’s how you can start with a Network-on-Chip (NoC) project in OMNeT++:

Steps to start Network-on-Chip Topology Projects Using OMNeT++

  1. Install OMNeT++

If you have not already installed OMNeT++, follow the installation procedures on the official OMNeT++ website.

  1. Create a New OMNeT++ Project
  1. Open OMNeT++ IDE.
  2. Select File > New > OMNeT++ Project.
  3. Choose Simple Network as the template.
  4. Name your project for sample NoCTopology.
  5. Click Finish to build the new project.
  1. Define the Network-on-Chip Topology in NED Files

In NoC systems, cores are typically organized in a mesh or grid pattern. Nodes like as cores communicate through routers or switches which connect the mesh/grid topology.

Example: NoCTopology.ned

This sample will outline a 2D Mesh topology, in which every node is linked to adjacent nodes through routers, typical in NoC architecture.

network NoCTopology

{

parameters:

int numRows = 4;  // Number of rows in the mesh

int numCols = 4;  // Number of columns in the mesh

submodules:

router[numRows * numCols]: Router;

connections:

// Connect each router to its neighbors

for i=0..numRows-1 {

for j=0..numCols-1 {

// Horizontal connection

if (j < numCols – 1) {

router[i * numCols + j].out –> router[i * numCols + j + 1].in;

}

// Vertical connection

if (i < numRows – 1) {

router[i * numCols + j].down –> router[(i + 1) * numCols + j].up;

}

}

}

}

simple module Router

{

parameters:

@display(“i=device/router”);

gates:

input in;

input down;

output out;

output up;

}

Explanation of the NED File:

  • NoCTopology: This describes the overall topology and uses two parameters: numRows and numCols that determine the number of rows and columns in the 2D mesh.
  • router: Every node in the NoC is signified as a Router module.
    • Horizontal connections: Routers in the similar row are connected horizontally for sample rightward.
    • Vertical connections: Routers in the identical column are connected vertically for instance downward.

This topology defines a 2D mesh network of routers. Each router has four gates:

  • in: Receive the messages from other routers.
  • out: Forward the messages to adjacent routers.
  • up and down: Characterize the links among the routers on adjacent rows.
  1. Define Router Behavior in C++

We replicate the routing and message maintaining in every router, we will require applying its behavior in C++. Every router will receive and forward packets to the appropriate neighboring routers according to the routing logic.

Example: Router.cc

#include <omnetpp.h>

class Router : public cSimpleModule

{

private:

cMessage *msg; // Message object for periodic transmission

protected:

virtual void initialize() override;

virtual void handleMessage(cMessage *msg) override;

void forwardPacket(cMessage *msg);

void sendPacket(cMessage *msg, const char *gateName);

public:

~Router();

};

Define_Module(Router);

void Router::initialize()

{

msg = new cMessage(“dataMessage”);

if (getIndex() == 0) {  // Start transmission from the first router

forwardPacket(msg);

}

}

void Router::handleMessage(cMessage *msg)

{

// Handle the incoming message and forward it

forwardPacket(msg);

}

 

void Router::forwardPacket(cMessage *msg)

{

// Example of simple routing: send packet to the next router (horizontal or vertical)

if (hasGate(“out”)) {

// Forward to right (horizontal)

sendPacket(msg, “out”);

} else if (hasGate(“down”)) {

// Forward down (vertical)

sendPacket(msg, “down”);

}

}

void Router::sendPacket(cMessage *msg, const char *gateName)

{

send(msg, gateName);  // Send the packet to the specified gate

}

Router::~Router()

{

cancelAndDelete(msg);

}

Explanation of the C++ Code:

  • initialize(): Start the message transmission from the first router.
  • handleMessage(): maintain the incoming messages and forwards them using a forwardPacket() function.
  • forwardPacket(): Apply a basic routing procedure which forward the packet to either a horizontal or vertical neighbor for sample based on available gates.
  • sendPacket(): Forward the packet by the specified gate such as either out or down.

This C++ code maintains the simple forwarding logic for a 2D mesh network. We can further increase the routing logic through applying further complex algorithms like XY routing, Torus routing, or adaptive routing according to traffic patterns or link failure conditions.

  1. Configure Simulation Parameters in omnetpp.ini

Now, setting replication parameters in the omnetpp.ini file to describe replication behavior, including timing and message intervals.

Example: omnetpp.ini

[General]

network = NoCTopology

sim-time-limit = 100s

**.router*.msgInterval = 1s

**.router*.out.delay = 0.5s

**.router*.down.delay = 0.5s

Explanation:

  • network: Requires the NED file for instance NoCTopology.ned to be used.
  • sim-time-limit: Limits the replication to 100 seconds for sim-time-limit.
  • msgInterval: Outlines the interval for message transmission for every router such as 1 second.
  • delay: Expresses the delay for forwarding the messages through every gate such as out and down.
  1. Compile the Project

Later describing the NED and C++ files, compile the project:

  1. Right-click on your project in the OMNeT++ IDE and choose Build Project.
  2. OMNeT++ will compile the code, generate an executable.
  1. Run the Simulation

We process for the replication:

  1. Right-click on the project folder and choose Run As > OMNeT++ Simulation.
  2. The replication will initialize, and we can follow the routing and message flow in the Network-on-Chip replication.
  1. Visualize and Analyze Results

OMNeT++ permits to envision the replication for examine the outcomes:

  • Simulation GUI: Envision the network’s behavior during the replication. We can check on how messages are sending through the NoC and examine node behavior.
  • Result Analysis: Use tools like scavetool to examine the performance metrics like as message latency, throughput, and network load.
  1. Extend the Simulation

We can improve the replication by several advanced features:

  • Routing Algorithms: Apply further sophisticated routing procedures such as adaptive routing, multicast, or deflection routing.
  • Traffic Models: Replicate the various congestion design for instance random, bursty, periodic to view on how the NoC performs below the different surroundings.
  • Fault Tolerance: Replicate the connection failures and check on how the network adapts or recovers using alternate routes.
  • Quality of Service (QoS): Apply the QoS policies for congestion prioritization.

Conclusion

By following these steps, you’ll have a basic Network-on-Chip (NoC) topology project in OMNeT++ using a 2D mesh network. You can modify and extend this simulation for more complex topologies, advanced routing protocols, and performance evaluations, making it suitable for various NoC research and development applications.

By using the following procedures, we had done the simulation process successfully for network-on-chip project using the tool of OMNet++and it also deliver the comprehensive procedures to simulate the process, detailed explanation for the given code snippets and deliver the sample project ideas for future enhancement. If you need more details regarding this process we will offered it.