How to Start Fibre Channel Arbitrated Loop Topology Using NS3

To start a Fibre Channel Arbitrated Loop (FC-AL) using NS3 tool which is a high-speed network topology mostly utilized within storage area networks (SANs). In a ring, this topology makes a unidirectional loop to associate the devices (nodes). For access, every single device medicates to the loop for data transmission.

While NS3 environment doesn’t have FC-AL then we can design their behavior getting through custom logic and the simple point-to-point or ring topology aspects within NS3 tool. Following is a basic structure to start and simulate the FC-AL Topology projects using NS3.

Steps to Start Fibre Channel Arbitrated Loop (FC-AL) Topology Project in NS3

Step 1: Set Up NS3

  1. Install NS3:
    • Go to NS3 webpage to download NS3 on the system.
    • We stick to the installation instructions.
  2. Verify Installation: We can execute a simple example to confirm NS3 is correctly installed:

./waf –run scratch/my_first

Step 2: Understand FC-AL

  • FC-AL Characteristics:
    • In a unidirectional loop (ring), nodes are associated
    • Single node sends at a time, which is discovered by arbitration.
    • In this topology, fault tolerance is attained via avoiding the failed nodes.

Step 3: Plan the Topology

  1. Define the number of devices:
    • For instance, we can describe the volume of devices that has 6 nodes within a ring.
  2. Set simulation goals:
    • We need to replicate the arbitration, data transfer, and fault handling.
  3. Use a logical ring structure:
    • Mimic the loop behavior by associating nodes within a circular manner to utilize logical ring structure.

Step 4: Set Up the Physical Ring Topology

  1. Create Nodes: In the FC-AL ring, we require to make the nodes.

NodeContainer nodes;

uint32_t numNodes = 6;

nodes.Create(numNodes);

  1. Set Up Point-to-Point Links: Generate unidirectional links to build a ring.

PointToPointHelper p2p;

p2p.SetDeviceAttribute(“DataRate”, StringValue(“4Gbps”)); // Fibre Channel speed

p2p.SetChannelAttribute(“Delay”, StringValue(“2ms”));     // Example delay

NetDeviceContainer devices;

for (uint32_t i = 0; i < numNodes; ++i) {

NetDeviceContainer link = p2p.Install(nodes.Get(i), nodes.Get((i + 1) % numNodes)); // Ring connection

devices.Add(link);

}

  1. Install Internet Stack: We able to insert a simple Internet stack to assist interaction.

InternetStackHelper stack;

stack.Install(nodes);

Ipv4AddressHelper address;

address.SetBase(“10.1.1.0”, “255.255.255.0”);

Ipv4InterfaceContainer interfaces = address.Assign(devices);

Step 5: Implement Arbitration Logic

  1. Arbitration Overview:
    • Every single node transmits an arbitration demand.
    • The node, which achieves the arbitration, sends information.
  2. Simulate Arbitration: We can replicate the arbitration to manage the access to the ring with the support of custom logic.

// Example pseudo-code for arbitration

for (uint32_t i = 0; i < numNodes; ++i) {

if (/* Node i wins arbitration */) {

// Transmit data

} else {

// Wait for next arbitration cycle

}

}

  1. NS3 Implementation: We execute the arbitration within the application layer to apply a custom application class or timers.

Step 6: Set Up Data Transmission

  1. Install Applications: Mimic data transfer among the nodes.
    • Server Application:

UdpEchoServerHelper echoServer(9); // Port 9

ApplicationContainer serverApp = echoServer.Install(nodes.Get(0)); // First node as server

serverApp.Start(Seconds(1.0));

serverApp.Stop(Seconds(10.0));

    • Client Applications:

for (uint32_t i = 1; i < numNodes; ++i) {

UdpEchoClientHelper echoClient(Ipv4Address(“10.1.1.1”), 9); // Server’s IP

echoClient.SetAttribute(“MaxPackets”, UintegerValue(10));

echoClient.SetAttribute(“Interval”, TimeValue(Seconds(1.0)));

echoClient.SetAttribute(“PacketSize”, UintegerValue(1024));

ApplicationContainer clientApp = echoClient.Install(nodes.Get(i));

clientApp.Start(Seconds(2.0));

clientApp.Stop(Seconds(10.0));

}

Step 7: Simulate Fault Handling

  1. Bypass Mechanism: Replicate the bypassing failed nodes exploiting logic.

for (uint32_t i = 0; i < numNodes; ++i) {

if (/* Node i fails */) {

// Skip node i in the ring

}

}

  1. Dynamic Link Changes: Inactivate or reconfigure links to utilize NS3’s NetDevice or Ipv4 API.

Step 8: Run and Analyze

  1. Run the Simulation: Now, we should execute the simulation using below command.

Simulator::Run();

Simulator::Destroy();

  1. Enable Packet Capture: Allow packet to seize and store .pcap files for analysis.

p2p.EnablePcapAll(“fc_al_topology”);

  1. Trace Logs: Allow logging for debugging:

export NS_LOG=”UdpEchoClientApplication=level_all|prefix_func”

./waf –run scratch/fc_al_topology

Example: Minimal NS3 Script for FC-AL Topology

#include “ns3/core-module.h”

#include “ns3/network-module.h”

#include “ns3/internet-module.h”

#include “ns3/point-to-point-module.h”

#include “ns3/applications-module.h”

using namespace ns3;

int main(int argc, char *argv[]) {

uint32_t numNodes = 6;

// Create nodes

NodeContainer nodes;

nodes.Create(numNodes);

// Set up Point-to-Point links for the ring

PointToPointHelper p2p;

p2p.SetDeviceAttribute(“DataRate”, StringValue(“4Gbps”));

p2p.SetChannelAttribute(“Delay”, StringValue(“2ms”));

NetDeviceContainer devices;

for (uint32_t i = 0; i < numNodes; ++i) {

NetDeviceContainer link = p2p.Install(nodes.Get(i), nodes.Get((i + 1) % numNodes));

devices.Add(link);

}

// Install Internet stack

InternetStackHelper stack;

stack.Install(nodes);

// Assign IP addresses

Ipv4AddressHelper address;

address.SetBase(“10.1.1.0”, “255.255.255.0”);

Ipv4InterfaceContainer interfaces = address.Assign(devices);

// Set up a UDP echo server on the first node

UdpEchoServerHelper echoServer(9);

ApplicationContainer serverApp = echoServer.Install(nodes.Get(0));

serverApp.Start(Seconds(1.0));

serverApp.Stop(Seconds(10.0));

// Set up UDP echo clients on other nodes

for (uint32_t i = 1; i < numNodes; ++i) {

UdpEchoClientHelper echoClient(interfaces.GetAddress(0), 9);

echoClient.SetAttribute(“MaxPackets”, UintegerValue(10));

echoClient.SetAttribute(“Interval”, TimeValue(Seconds(1.0)));

echoClient.SetAttribute(“PacketSize”, UintegerValue(1024));

ApplicationContainer clientApp = echoClient.Install(nodes.Get(i));

clientApp.Start(Seconds(2.0));

clientApp.Stop(Seconds(10.0));

}

// Enable packet capture

p2p.EnablePcapAll(“fc_al_topology”);

// Run the simulation

Simulator::Run();

Simulator::Destroy();

return 0;

}

Step 9: Compile and Run

  1. We want to save the script like fc_al_topology.cc.
  2. Then, we compile and execute it:

./waf –run fc_al_topology

Step 10: Enhance the Simulation

  • Dynamic Arbitration:
    • Mimic arbitration among the nodes to utilize timers or events.
  • Fault Tolerance:
    • We able to replicate the failure recovery by means of actively bypassing failed nodes.
  • Traffic Analysis:
    • Estimate the performance metrics like throughput, delay, and packet loss to use NS3’s flow monitor for traffic analysis.

Finally, the comprehensive simulation approach and example coding to Fibre Channel Arbitrated Loop Topology project is presented in a systematized manner and we are equipped to expand on it if desired.

To begin Fibre Channel Arbitrated Loop Topology projects with NS3, we will execute and simulate based on your specific requirements. We will support you throughout the entire process to ensure your project is completed successfully. Get best project performance from our developers.