How to Implement Intra Switching Protocols in ns3

To implement intra-switching protocols (such as STP, VLAN, etc.) in ns3, we follow several steps. Ns3 does not support these types of Layer 2 protocols so, we have to create a custom module for simulating this protocol. We can also model the behaviour of switches and extent some protocols using ns3. The following step will help to simulate the basic VLAN switching using ns-3.

Step-by-Step Guide to Implementing VLAN Switching in ns-3

1. Set Up Your Environment

Ensure that ns-3 is installed.

2. Create a New ns-3 Script

Create a new simulation script in the scratch directory of the ns3 installation. For example, create a file named vlan-switching-simulation.cc.

cd ns3.xx

cd scratch

touch vlan-switching-simulation.cc

3. Include Necessary Headers

In your vlan-switching-simulation.cc file, include the necessary headers for the simulation.

#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”

#include “ns3/csma-module.h”

 

using namespace ns3;

4. Set Up the Network Topology

Define the network topology. We will create a basic topology with a few nodes connected via CSMA (simulating a switch) and set up VLANs.

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

{

CommandLine cmd;

cmd.Parse (argc, argv);

// Create nodes

NodeContainer nodes;

nodes.Create (6);

// Create CSMA channels (simulating a switch)

CsmaHelper csma;

csma.SetChannelAttribute (“DataRate”, StringValue (“100Mbps”));

csma.SetChannelAttribute (“Delay”, TimeValue (NanoSeconds (6560)));

NetDeviceContainer devices = csma.Install (nodes);

// Install the internet stack on nodes

InternetStackHelper stack;

stack.Install (nodes);

// Assign IP addresses to devices

Ipv4AddressHelper address;

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

Ipv4InterfaceContainer interfaces = address.Assign (devices);

// Set up applications (e.g., a UDP echo server and client)

UdpEchoServerHelper echoServer (9);

ApplicationContainer serverApps = echoServer.Install (nodes.Get (5));

serverApps.Start (Seconds (1.0));

serverApps.Stop (Seconds (10.0));

UdpEchoClientHelper echoClient (interfaces.GetAddress (5), 9);

echoClient.SetAttribute (“MaxPackets”, UintegerValue (1));

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

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

ApplicationContainer clientApps = echoClient.Install (nodes.Get (0));

clientApps.Start (Seconds (2.0));

clientApps.Stop (Seconds (10.0));

// Enable tracing

AsciiTraceHelper ascii;

csma.EnableAsciiAll (ascii.CreateFileStream (“vlan-switching-simulation.tr”));

csma.EnablePcapAll (“vlan-switching-simulation”);

// Run the simulation

Simulator::Run ();

Simulator::Destroy ();

return 0;

}

5. Add VLAN Configuration

To simulate VLANs, we need to create separate CSMA channels for each VLAN. Let’s assume we have two VLANs (VLAN 10 and VLAN 20).

Update the script to create two separate CSMA channels:

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

{

CommandLine cmd;

cmd.Parse (argc, argv);

// Create nodes

NodeContainer vlan10Nodes, vlan20Nodes;

vlan10Nodes.Create (3);

vlan20Nodes.Create (3);

// Create CSMA channels (simulating a switch with VLANs)

CsmaHelper csma;

csma.SetChannelAttribute (“DataRate”, StringValue (“100Mbps”));

csma.SetChannelAttribute (“Delay”, TimeValue (NanoSeconds (6560)));

NetDeviceContainer vlan10Devices = csma.Install (vlan10Nodes);

NetDeviceContainer vlan20Devices = csma.Install (vlan20Nodes);

// Install the internet stack on nodes

InternetStackHelper stack;

stack.Install (vlan10Nodes);

stack.Install (vlan20Nodes);

// Assign IP addresses to devices

Ipv4AddressHelper address;

address.SetBase (“10.1.10.0”, “255.255.255.0”);

Ipv4InterfaceContainer vlan10Interfaces = address.Assign (vlan10Devices);

address.SetBase (“10.1.20.0”, “255.255.255.0”);

Ipv4InterfaceContainer vlan20Interfaces = address.Assign (vlan20Devices);

// Set up applications (e.g., a UDP echo server and client)

UdpEchoServerHelper echoServer (9);

ApplicationContainer serverApps = echoServer.Install (vlan20Nodes.Get (2));

serverApps.Start (Seconds (1.0));

serverApps.Stop (Seconds (10.0));

UdpEchoClientHelper echoClient (vlan20Interfaces.GetAddress (2), 9);

echoClient.SetAttribute (“MaxPackets”, UintegerValue (1));

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

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

ApplicationContainer clientApps = echoClient.Install (vlan10Nodes.Get (0));

clientApps.Start (Seconds (2.0));

clientApps.Stop (Seconds (10.0));

// Enable tracing

AsciiTraceHelper ascii;

csma.EnableAsciiAll (ascii.CreateFileStream (“vlan-switching-simulation.tr”));

csma.EnablePcapAll (“vlan-switching-simulation”);

// Run the simulation

Simulator::Run ();

Simulator::Destroy ();

return 0;

}

6. Build and Run the Simulation

After writing the script, we need to build and run it.

./waf build

./waf –run scratch/vlan-switching-simulation

7. Analyze the Results

After running the simulation, we can analyze the results using the generated trace files (vlan-switching-simulation.tr and vlan-switching-simulation-0-0.pcap).

Overall, from the steps and the examples scripts given above we all get know how to implement intra-switching protocol- VLAN switching in ns3 by creating a separate CSMA channels for each VLAN, which does not directly support in ns3 tool.

We offer support for all protocols involving ns3 in the switching process, including STP, VLAN, and more, to assist with your research endeavours.