How to Begin Implement Network Bridging in NS3

To begin implementing the network bridging using ns3 that encompasses to replicate a network scenario in which numerous nodes perform like bridges transmitting the packets among diverse network segments. It permits devices within various network segments for interacting while they were portion of the similar network. Below is a detailed stepwise approach to execute the network bridging in ns3:

Steps to Begin Implement Network Bridging in NS3

1. Understand Network Bridging in ns3

• At the data link layer (Layer 2), Network Bridge is utilized for connecting two or more network segments.
• Bridging is achieved with the support of BridgeNetDevice class in ns3 that permits a node to perform like a bridge through sending the packets among network devices.

2. Set Up the ns3 Environment

• Make sure that we have installed ns3 and working properly on the system:

git clone https://gitlab.com/nsnam/ns-3-dev.git

cd ns-3-dev

./ns3 configure –enable-examples –enable-tests

./ns3 build

• Confirm the installation by executing:

./ns3 run hello-simulator

3. Design the Network Topology

• Make a network topology including several network segments which are associated via a bridge node.
• For instance:
  • Segment 1: Node1 <-> BridgeNode.
  • Segment 2: Node2 <-> BridgeNode.

4. Create the Bridge Node

• Combine numerous network devices at bridge node to leverage the BridgeNetDevice class.
• Integrate BridgeNetDevice to the node and then link it to other nodes or networks.

5. Steps to Implement Bridging

(a) Create Nodes

• Make nodes for the network communication.

NodeContainer nodes;

nodes.Create(3); // Node 0 and Node 2 will communicate via Node 1 (BridgeNode)

(b) Install Network Devices

• We can install network devices using CsmaHelper or PointToPointHelper.

CsmaHelper csma;

NetDeviceContainer dev1 = csma.Install(NodeContainer(nodes.Get(0), nodes.Get(1)));

NetDeviceContainer dev2 = csma.Install(NodeContainer(nodes.Get(1), nodes.Get(2)));

(c) Configure the Bridge

• Integrate a BridgeNetDevice to the bridge node and also connect the devices.

Ptr<BridgeNetDevice> bridge = CreateObject<BridgeNetDevice>();

nodes.Get(1)->AddDevice(bridge);

bridge->AddBridgePort(dev1.Get(1)); // Port connected to Segment 1

bridge->AddBridgePort(dev2.Get(0)); // Port connected to Segment 2

(d) Install Internet Stack

• For higher-layer interaction, we need to install the InternetStackHelper at nodes.

InternetStackHelper stack;

stack.Install(nodes);

(e) Assign IP Addresses

• Allocate an IP addresses to utilize Ipv4AddressHelper.

Ipv4AddressHelper address;

address.SetBase(“192.168.1.0”, “255.255.255.0”);

address.Assign(dev1);

address.Assign(dev2);

(f) Install Applications

• Replicate traffic through the bridged segments to apply UdpEchoClient and UdpEchoServer or other applications.

UdpEchoServerHelper echoServer(9);

ApplicationContainer serverApp = echoServer.Install(nodes.Get(2));

serverApp.Start(Seconds(1.0));

serverApp.Stop(Seconds(10.0));

UdpEchoClientHelper echoClient(Ipv4Address(“192.168.1.2”), 9);

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

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

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

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

clientApp.Start(Seconds(2.0));

clientApp.Stop(Seconds(10.0));

6. Example Code for Network Bridging

Here’s a comprehensive instance that illustrating the network bridging using ns3:

#include “ns3/core-module.h”

#include “ns3/network-module.h”

#include “ns3/csma-module.h”

#include “ns3/internet-module.h”

#include “ns3/applications-module.h”

#include “ns3/bridge-module.h”

using namespace ns3;

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

CommandLine cmd;

cmd.Parse(argc, argv);

// Create nodes

NodeContainer nodes;

nodes.Create(3); // Node 0 and Node 2 communicate via Node 1 (Bridge)

// Install CSMA devices

CsmaHelper csma;

NetDeviceContainer dev1 = csma.Install(NodeContainer(nodes.Get(0), nodes.Get(1)));

NetDeviceContainer dev2 = csma.Install(NodeContainer(nodes.Get(1), nodes.Get(2)));

// Configure the Bridge on Node 1

Ptr<BridgeNetDevice> bridge = CreateObject<BridgeNetDevice>();

nodes.Get(1)->AddDevice(bridge);

bridge->AddBridgePort(dev1.Get(1)); // Port for Segment 1

bridge->AddBridgePort(dev2.Get(0)); // Port for Segment 2

// Install Internet stack

InternetStackHelper stack;

stack.Install(nodes);

// Assign IP addresses

Ipv4AddressHelper address;

address.SetBase(“192.168.1.0”, “255.255.255.0”);

address.Assign(dev1);

address.Assign(dev2);

// Set up applications

UdpEchoServerHelper echoServer(9);

ApplicationContainer serverApp = echoServer.Install(nodes.Get(2));

serverApp.Start(Seconds(1.0));

serverApp.Stop(Seconds(10.0));

UdpEchoClientHelper echoClient(Ipv4Address(“192.168.1.2”), 9);

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

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

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

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

clientApp.Start(Seconds(2.0));

clientApp.Stop(Seconds(10.0));

// Run simulation

Simulator::Run();

Simulator::Destroy();

return 0;

}

7. Validate the Bridging

• Confirm that packets are sent via the bridge to leverage packet traces or logs.
• Observe the traffic through the bridge with FlowMonitor.

8. Enhance the Simulation

• Integrate additional network segments or nodes for analysing the scalability.
• To monitor the behavior of bridging, we need to test with link failures or node failures.

By using NS3, we built a thorough implementation procedure for executing the Network Bridging and refining the simulation with sample coding. We have the capacity to enhance it further for additional understanding regarding this Network Bridging if necessary.