How to Start Link Aggregation Control Protocol Projects Using NS3

To start the Link Aggregation Control Protocol (LACP) in NS3 that is described by IEEE 802.3ad, which allow integrating many physical network links to a single logical link. It maximizes bandwidth and also it offers redundancy for fault tolerance. Although NS3 doesn’t support LACP directly then we can be replicated their behavior by means of handling the link aggregation and traffic distribution manually or through a custom execution. The following is a step-by-step guide to start and simulate the LACP projects using NS3.

Steps to Start LACP Projects in NS3

  1. Understand LACP
  • Key Features of LACP:
    • It integrates numerous physical links to a single logical link like Link Aggregation Group or LAG.
    • LACP offers load balancing over combined links.
    • Makes sure that fault tolerance by redeploying traffic as per link failure.
  • Applications:
    • It supports for bandwidth scaling within data centers and enterprise networks.
    • LACP used in resilient network designs including redundancy.
  1. Set Up NS3
  1. Install NS3:

sudo apt update

sudo apt install g++ python3 git cmake

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

cd ns-3-dev

./waf configure

./waf build

  1. Verify Installation:

./waf –run scratch/my-first

  1. Simulate LACP in NS3

While NS3 doesn’t have built-in LACP then we can simulate it to utilize:

  1. Logical Link Aggregation:
    • We can use several PointToPoint links among the nodes and then combine them on the application level.
  2. Traffic Distribution:
    • Depends on the hashing (e.g., IP, port) or round-robin logic to deliver traffic over links.
  3. Fault Tolerance:
    • To replicate the link failures and actively redeploy traffic.
  1. Example: LACP Simulation

Topology:

  • Two nodes such as Node A and Node B are linked through three physical links.
  • Traffic is load-balanced over the links.

Code:

#include “ns3/core-module.h”

#include “ns3/network-module.h”

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

#include “ns3/internet-module.h”

#include “ns3/applications-module.h”

using namespace ns3;

void SimulateLinkFailure(Ptr<NetDevice> link) {

link->SetDown();

NS_LOG_UNCOND(“Simulated link failure at ” << Simulator::Now().GetSeconds() << “s”);

}

int main() {

// Enable logging

LogComponentEnable(“LacpSimulation”, LOG_LEVEL_INFO);

// Create nodes

NodeContainer nodes;

nodes.Create(2); // Node A and Node B

// Create multiple links between nodes

PointToPointHelper pointToPoint;

pointToPoint.SetDeviceAttribute(“DataRate”, StringValue(“1Gbps”));

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

NetDeviceContainer link1 = pointToPoint.Install(nodes);

NetDeviceContainer link2 = pointToPoint.Install(nodes);

NetDeviceContainer link3 = pointToPoint.Install(nodes);

// Install Internet stack

InternetStackHelper stack;

stack.Install(nodes);

// Assign IP addresses for each link

Ipv4AddressHelper ipv4;

ipv4.SetBase(“10.1.1.0”, “255.255.255.0”);

Ipv4InterfaceContainer interfaces1 = ipv4.Assign(link1);

ipv4.SetBase(“10.1.2.0”, “255.255.255.0”);

Ipv4InterfaceContainer interfaces2 = ipv4.Assign(link2);

ipv4.SetBase(“10.1.3.0”, “255.255.255.0”);

Ipv4InterfaceContainer interfaces3 = ipv4.Assign(link3);

// Simulate traffic

uint16_t port = 9;

OnOffHelper onOff(“ns3::UdpSocketFactory”, Address(InetSocketAddress(interfaces1.GetAddress(1), port)));

onOff.SetAttribute(“DataRate”, StringValue(“500Mbps”));

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

ApplicationContainer app = onOff.Install(nodes.Get(0));

app.Start(Seconds(1.0));

app.Stop(Seconds(10.0));

PacketSinkHelper sink(“ns3::UdpSocketFactory”, Address(InetSocketAddress(Ipv4Address::GetAny(), port)));

ApplicationContainer sinkApp = sink.Install(nodes.Get(1));

sinkApp.Start(Seconds(1.0));

sinkApp.Stop(Seconds(10.0));

// Simulate link failure

Simulator::Schedule(Seconds(5.0), &SimulateLinkFailure, link2.Get(0));

// Run simulation

Simulator::Run();

Simulator::Destroy();

return 0;

}

  1. Explanation of the Code
  1. Multiple Links:
    • From above code, three PointToPoint links mimic a link aggregation group.
  2. Traffic Distribution:
    • The application transmits traffic across main link and redundancy can be inserted through the custom distribution logic or manual routing.
  3. Link Failure:
    • At runtime, replicate link failure by setting a link down using SetDown() method.
  1. Custom Traffic Distribution Logic

We can be executed load balancing through the links:

  1. Round-Robin Distribution:
    • Alternative packets over available links.
  2. Hash-Based Distribution:
    • In this distribution, we can utilize a hash function on packet attributes such as source/destination IP and port.

Example Hash-Based Distribution:

uint32_t HashFunction(Ipv4Address src, Ipv4Address dest, uint16_t port) {

return (src.Get() + dest.Get() + port) % 3; // Assuming 3 links

}

  1. Advanced Features

Monitor Link Utilization

We need to observe the traffic across each link estimating the load balancing:

Ptr<NetDevice> device = link1.Get(0);

device->TraceConnectWithoutContext(“PhyRxDrop”, MakeCallback(&RxDropTrace));

Fault Tolerance

Once a link flops then redeploy traffic automatically:

void HandleLinkFailure(Ptr<NetDevice> failedLink) {

NS_LOG_UNCOND(“Handling failure for link: ” << failedLink);

// Redistribute traffic across other links

}

As a finial point, you can get to know more about how to approach and simulate the Link Aggregation Control Protocol (LACP) Projects through above steps that contains relevant example snippets with explanation using NS3 environment. If you want any more information on this topic, we will send it to you.

We give you a comprehensive guide to help you initiate and simulate LACP projects using the NS3 tool. We’ll walk you through the essential steps and provide detailed explanations along the way.