To simulate a Fibre Channel Arbitrated Loop (FC-AL) Topology using OMNeT++, which contains modeling a closed-loop architecture in which all devices (nodes) are distribute the similar physical medium and use arbitration to obtain control of the loop for communication. This kind of topology is usually used in storage area networks (SANs) and high-speed interconnects, where several devices are communicate over a unique loop without a dedicated switch.
Here’s a step-by-step method on how to replicate a Fibre Channel Arbitrated Loop (FC-AL) Topology in OMNeT++ using the INET framework.
Steps to Simulate Fibre Channel Arbitrated Loop (FC-AL) in OMNeT++
- Install OMNeT++ and INET Framework:
Make certain OMNeT++ and the INET framework are installed and appropriately configured. The INET framework is needed for describing nodes, links, and the network environment. For Fibre Channel specifics, we may require to make a custom protocols and behaviours for FC-AL arbitration.
- We can download and install OMNeT++.
- Download and install the INET Framework.
- Understand Fibre Channel Arbitrated Loop Topology:
Before configuring the simulation, it’s significant to comprehend that in FC-AL:
- Devices are connected in a closed-loop (ring) topology.
- Only one device can send data at a time after winning arbitration.
- Devices must request permission (arbitrate) to access the loop.
- The loop can comprise up to 126 nodes (devices), with each node performing as a sender or receiver at distinct times.
- Define the FC-AL Topology in NED File:
The NED file describes how devices are connected in the loop. Each device is connected to its next neighbour, and the last device associates back to the initial one, forming a loop.
network FibreChannelALNetwork
{
parameters:
int numNodes = default(5); // Number of devices on the Fibre Channel loop
submodules:
// Define Fibre Channel nodes (devices)
node[numNodes]: <FCNodeType> {
@display(“p=100+200*i,100”);
}
connections allowunconnected:
// Connect nodes in a loop (ring topology)
for i=0..numNodes-2 {
node[i].fcg++ <–> FibreChannelLink <–> node[i+1].fcg++;
}
// Complete the loop by connecting the last node back to the first node
node[numNodes-1].fcg++ <–> FibreChannelLink <–> node[0].fcg++;
}
In this example:
- numNodes describes the number of nodes (devices) on the loop.
- node[numNodes] denotes the Fibre Channel devices.
- FibreChannelLink signifies the Fibre Channel connection among the nodes.
- The ring topology is formed by connecting the last node back to the initial node.
- Define Node Types for FC-AL Devices:
As INET framework doesn’t natively support Fibre Channel, we will be required to make a custom node types and behaviour to replicate FC-AL arbitration and data transmission. The nodes must manage the arbitration mechanism in which one node manages the loop at a time.
Here’s an instance of describing a custom FCNodeType:
simple FCNodeType
{
parameters:
@display(“i=device/pc”); // Icon for Fibre Channel nodes
gates:
input fcg; // Gate for Fibre Channel communication
output fcg;
}
This basic FCNodeType will denote each device on the Fibre Channel loop.
- Model Arbitration and Data Transmission:
We want to execute a custom protocol or logic to replicate the arbitration mechanism in FC-AL. For instance:
- Each node must “arbitrate” to request access to the loop.
- Only one node can send data at a time, and other nodes must wait.
- After transmission, the node issues control of the loop, and other nodes can arbitrate for the loop.
This can be executed in the C++ modules or behavior scripts in OMNeT++. Here’s a sample of how we can model arbitration behaviour in a basic form:
class FCNode : public cSimpleModule
{
private:
bool isArbitrating;
cMessage *arbitrateMsg;
cMessage *transmitMsg;
protected:
virtual void initialize() override {
// Set up arbitration message
arbitrateMsg = new cMessage(“arbitrate”);
transmitMsg = new cMessage(“transmit”);
scheduleAt(simTime() + uniform(1, 3), arbitrateMsg); // Start arbitration after a random delay
}
virtual void handleMessage(cMessage *msg) override {
if (msg == arbitrateMsg) {
// Request to gain control of the loop
isArbitrating = true;
EV << “Node ” << getId() << ” is arbitrating for the loop\n”;
scheduleAt(simTime() + 1, transmitMsg); // Wait for arbitration result
}
else if (msg == transmitMsg && isArbitrating) {
// Simulate data transmission if this node won arbitration
EV << “Node ” << getId() << ” won arbitration and is transmitting data\n”;
send(createDataPacket(), “fcg”); // Send data packet on the loop
scheduleAt(simTime() + uniform(1, 2), arbitrateMsg); // Re-arbitrate after a delay
}
delete msg;
}
cPacket *createDataPacket() {
cPacket *pkt = new cPacket(“DataPacket”);
pkt->setByteLength(1024); // Set packet size
return pkt;
}
};
This is a simple model where each node requests arbitration and sends data when it acquires control of the loop.
- Configure INI File for Simulation:
In the omnetpp.ini file, we can set up the parameters for the simulation, like arbitration intervals, transmission rates, and the amount of nodes.
[General]
network = FibreChannelALNetwork
sim-time-limit = 60s # Set simulation time
# Configuring FC-AL behavior (random delays for arbitration and transmission)
*.node[*].arbitrateInterval = uniform(1s, 2s)
*.node[*].transmissionTime = uniform(1s, 3s)
This configuration:
- Sets the simulation time to 60 seconds.
- Randomizes the arbitration and transmission intervals to mimic real-world behaviour in which devices contend for the loop.
- Run the Simulation:
- We can open OMNeT++ IDE, compile the project, and run the simulation.
- Utilize Qtenv to visualize the network and monitor how nodes arbitrate and send data on the Fibre Channel loop.
In the course of the simulation, we can be monitor how only one device sends at a time after arbitration and how the loop make certain that the devices are distributes the communication medium.
- Analyze the Results:
OMNeT++ offers detailed logs and statistical information to examine the behaviour of the simulation. Parameters to track contain:
- Arbitration success rate: How frequently each node wins control of the loop.
- Throughput: Assess the amount of data sent by each node.
- Latency: Calculate the time from arbitration request to data transmission.
- Packet Loss: Detect any dropped packets or transmission errors in the course of arbitration.
Utilize Plove or Scave to make a graphs and investigate the simulation data.
- Advanced Features (Optional):
We can prolong the simulation by inserting more advanced aspects such as:
- Error Handling: Execute an error scenarios like failed arbitration or dropped packets.
- Priority Arbitration: Replicate distinct priority levels for devices, in which some nodes have higher priority during arbitration.
- Physical Layer Simulation: Mimic lower-layer features like signal propagation delay or noise in the physical medium.
Example of Adding Error Handling:
We can launch errors in arbitration or data transmission, in which nodes are occasionally fail to acquire control of the loop:
if (uniform(0, 1) < 0.1) {
EV << “Node ” << getId() << ” failed arbitration\n”;
isArbitrating = false; // Arbitration failed
} else {
EV << “Node ” << getId() << ” won arbitration\n”;
isArbitrating = true;
}
Summary:
- Topology Definition: Utilize NED to describe a closed-loop architecture where nodes are associated in a ring.
- Node Behavior: Execute FC-AL arbitration and transmission behaviour in C++ or OMNeT++ behaviour scripts.
- Simulation Configuration: We can use the INI file to set up arbitration intervals, transmission times, and node parameters.
- Run and Analyze: Run the simulation, and utilize OMNeT++ tools to examine arbitration success, throughput, and latency.
Through this brief approach, you can obtain to comprehend more about the simulation process and their examples regarding Fibre Channel Arbitrate Loop Topology projects using OMNeT++ platform. We plan to offer the more information concerning this projects, if needed. To continue modeling in projects involving fiber channel arbitrate loop topology We will give you detailed instructions with the best outcomes using the OMNeT++ tool. If required, we will provide additional information on this subject in your designated area along with the simulation’s findings. To help you get the best results from phdprime.com, we work on high-speed interconnects and storage area networks (SANs) related to your projects.
