How to Begin Implement Link Aggregation Protocol in NS3

To implement a Link Aggregation Control Protocol (LACP) is part of the IEEE 802.3ad standard, calculated for associate the numerous physical connections in single logical connection for redundancy and improved the bandwidth. Applying LACP in NS3 has includes the replicate a dynamic negotiation and aggregation of connection among network devices.

Here’s how to begin implementing LACP in NS-3:

Steps to Begin Implement Link Aggregation Protocol in NS3

Step 1: Understand LACP

1. Key Features:
   • Associate the numerous physical connections in single logical connection.
   • It delivers the redundancy and load balancing.
   • Dynamically handles the connection aggregation using LACP communication.
2. Core Concepts:
   • Actor: Device is starting the LACP.
   • Partner: Device is response the LACP.
   • LACPDU (LACP Data Unit): Packet are replaced the negotiate connection aggregation.
     • It contains the system ID, port ID, and aggregation status.

Step 2: Set Up NS-3 Environment

1. Create a Protocol Directory:
   • Make a new directory below src/, e.g., src/lacp/.
2. Add Necessary Files:
   • lacp-protocol.h: LACP has includes a Header file.
   • lacp-protocol.cc: then execute a file.
   • lacp-helper.h and lacp-helper.cc: Helper classes for incorporate.
3. Update Build System:
   • Alter the wscript in src/ for involves the new LACP module.

Step 3: Design LACP Protocol

Define the Protocol Class

Make a class for LACP which maintain the LACPDU altercation and connection aggregation logic.

Header File (lacp-protocol.h)

#include “ns3/application.h”

#include <map>

class LacpProtocol : public ns3::Application {

public:

static ns3::TypeId GetTypeId (void);

LacpProtocol ();

virtual ~LacpProtocol ();

void StartApplication () override;

void StopApplication () override;

void SendLacpdu ();

void ReceiveLacpdu (ns3::Ptr<ns3::Packet> packet);

void AggregateLinks ();

private:

struct LinkInfo {

uint32_t portId;

bool active; // Indicates if the link is part of the aggregation

};

uint32_t m_systemId;                       // System ID for LACP

std::map<uint32_t, LinkInfo> m_links;      // List of links and their states

ns3::Ptr<ns3::Socket> m_socket;            // Communication socket

};

Implement Core Functions

Start and Stop the Protocol

Set and clean up the LACP during replication.

void LacpProtocol::StartApplication () {

m_socket = ns3::Socket::CreateSocket(GetNode(), ns3::TypeId::LookupByName(“ns3::UdpSocketFactory”));

m_socket->Bind();

m_socket->SetRecvCallback(MakeCallback(&LacpProtocol::ReceiveLacpdu, this));

SendLacpdu(); // Start sending LACPDUs

}

void LacpProtocol::StopApplication () {

if (m_socket) {

m_socket->Close();

}

}

Send LACPDU

Propagate the LACPDU communication has encompassing the connection information.

void LacpProtocol::SendLacpdu () {

for (const auto& link : m_links) {

ns3::Ptr<ns3::Packet> lacpdu = ns3::Create<ns3::Packet> ();

// Serialize LACPDU (System ID, Port ID, Active Status)

// …

// Broadcast LACPDU

m_socket->SendTo(lacpdu, 0, ns3::InetSocketAddress(ns3::Ipv4Address::GetBroadcast(), 9999));

}

// Schedule the next LACPDU

ns3::Simulator::Schedule(ns3::Seconds(1.0), &LacpProtocol::SendLacpdu, this);

}

Receive LACPDU

Develop the incoming LACPDU messages and bring up-to-date connection states.

void LacpProtocol::ReceiveLacpdu (ns3::Ptr<ns3::Packet> packet) {

// Deserialize LACPDU

uint32_t partnerSystemId = …; // Extract partner’s system ID

uint32_t partnerPortId = …;   // Extract partner’s port ID

bool partnerActive = …;       // Extract partner’s active status

// Update link states

for (auto& link : m_links) {

if (link.second.portId == partnerPortId) {

link.second.active = partnerActive;

}

}

AggregateLinks(); // Recalculate aggregated links

}

Aggregate Links

Define that connections for aggregate according to LACPDU negotiation.

void LacpProtocol::AggregateLinks () {

// Aggregate links with active status

for (auto& link : m_links) {

if (link.second.active) {

// Mark the link as aggregated

// …

} else {

// Mark the link as inactive

// …

}

}

}

Step 4: Write a Helper Class

Make a helper class for incorporating LACP in replication.

#include “lacp-protocol.h”

class LacpHelper {

public:

void Install (ns3::NodeContainer nodes, uint32_t systemIdStart) {

uint32_t systemId = systemIdStart;

for (auto it = nodes.Begin(); it != nodes.End(); ++it, ++systemId) {

ns3::Ptr<LacpProtocol> lacp = ns3::CreateObject<LacpProtocol>();

lacp->SetSystemId(systemId);

(*it)->AddApplication(lacp);

}

}

};

Step 5: Write a Simulation Script

Example Simulation Script

#include “ns3/core-module.h”

#include “ns3/network-module.h”

#include “ns3/internet-module.h”

#include “lacp-helper.h”

using namespace ns3;

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

NodeContainer nodes;

nodes.Create(4);

PointToPointHelper p2p;

p2p.SetDeviceAttribute(“DataRate”, StringValue(“100Mbps”));

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

for (uint32_t i = 0; i < nodes.GetN() – 1; ++i) {

p2p.Install(nodes.Get(i), nodes.Get(i + 1));

}

LacpHelper lacpHelper;

lacpHelper.Install(nodes, 1);

Simulator::Run();

Simulator::Destroy();

return 0;

}

Step 6: Compile and Run

1. Build the Protocol:

./waf configure

./waf build

1. Run the Simulation:

./waf –run your-script

Step 7: Analyze and Extend

1. Tracing:
   • AsciiTraceHelper or PcapHelper to use and examine the LACPDU exchanges.
2. Enhancements:
   • Apply the changed load-balancing approaches.
   • Investigate by dynamic connection failures and recoveries.

We have showcased the valuable information on how to simulate the Link Aggregation Control Protocol project in the ns3 simulation environment. A complementary manual will be issued to answer further queries.