How to Calculate Network Load balance factor in ns3

To calculate the network load balance factor h in ns3, we have to measure the distribution of traffic across various nodes or links in the network. A well-balanced network will have a more uniform distribution of traffic and an unbalanced network will have some nodes or links more heavily loaded comparing to others.

The load balance factor hhh can be calculated using the formula: h=Max LoadAverage Loadh = \frac{\text{Max Load}}{\text{Average Load}}h=Average LoadMax Load​ where:

• Max Load\text{Max Load}Max Load is the maximum load on any node or link.
• Average Load\text{Average Load}Average Load is the average load across all nodes or links.

Steps for calculating network load Balance Factor

1. Set Up the Simulation Environment:
   • Make sure that ns3 is installed in the computer. If not, install it and include necessary modules.
2. Create Network Topology:
   • Create nodes and configure the network topology.
   • Set up point-to-point links, Wi-Fi devices, and mobility models for the nodes if required.
3. Implement Load Measurement:
   • Measure the load on every node or link. We can achieve this by tracking the number of packets or bytes processed by each node or link.
4. Enable Tracing and Metrics Collection:
   • To capture relevant metrics such as packet counts or byte counts on nodes or links, enable tracing.
5. Run the Simulation:
   • Execute the simulation and collect the trace data.
6. Calculate Load Balance Factor:
   • Post-process the trace data to calculate the maximum load and average load.
   • Calculate the load balance factor hhh.

Example of a simple Network Load Balance Factor

Create a basic set up of network, measure the load on nodes, and calculate the load balance factor in ns3.

#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/mobility-module.h”

#include “ns3/log.h”

using namespace ns3;

NS_LOG_COMPONENT_DEFINE (“LoadBalanceFactorExample”);

std::map<uint32_t, uint64_t> nodePacketCounts;

void PacketReceived (Ptr<const Packet> packet, const Address &address)

{

uint32_t nodeId = InetSocketAddress::ConvertFrom (address).GetIpv4 ().Get ();

nodePacketCounts[nodeId]++;

}

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

{

// Set up logging

LogComponentEnable (“UdpClient”, LOG_LEVEL_INFO);

LogComponentEnable (“UdpServer”, LOG_LEVEL_INFO);

// Create nodes

NodeContainer nodes;

nodes.Create (4);

// Install Mobility model

MobilityHelper mobility;

mobility.SetMobilityModel (“ns3::ConstantPositionMobilityModel”);

mobility.Install (nodes);

// Set node positions

nodes.Get (0)->GetObject<MobilityModel> ()->SetPosition (Vector (0, 0, 0));

nodes.Get (1)->GetObject<MobilityModel> ()->SetPosition (Vector (50, 0, 0));

nodes.Get (2)->GetObject<MobilityModel> ()->SetPosition (Vector (100, 0, 0));

nodes.Get (3)->GetObject<MobilityModel> ()->SetPosition (Vector (150, 0, 0));

// Create point-to-point links

PointToPointHelper pointToPoint;

pointToPoint.SetDeviceAttribute (“DataRate”, StringValue (“5Mbps”));

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

NetDeviceContainer devices;

devices.Add (pointToPoint.Install (nodes.Get (0), nodes.Get (1)));

devices.Add (pointToPoint.Install (nodes.Get (1), nodes.Get (2)));

devices.Add (pointToPoint.Install (nodes.Get (2), nodes.Get (3)));

// Install Internet stack

InternetStackHelper internet;

internet.Install (nodes);

// Assign IP addresses

Ipv4AddressHelper address;

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

Ipv4InterfaceContainer interfaces = address.Assign (devices);

// Install and start applications on nodes

uint16_t port = 9; // Discard port (RFC 863)

UdpServerHelper server (port);

ApplicationContainer serverApp = server.Install (nodes.Get (3));

serverApp.Start (Seconds (1.0));

serverApp.Stop (Seconds (10.0));

UdpClientHelper client (interfaces.GetAddress (3), port);

client.SetAttribute (“MaxPackets”, UintegerValue (320));

client.SetAttribute (“Interval”, TimeValue (MilliSeconds (50)));

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

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

clientApp.Start (Seconds (2.0));

clientApp.Stop (Seconds (10.0));

// Trace received packets

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

{

nodes.Get (i)->GetObject<Ipv4> ()->GetObject<Ipv4L3Protocol> ()->TraceConnectWithoutContext (“Rx”, MakeCallback (&PacketReceived));

}

// Run the simulation

Simulator::Stop (Seconds (11.0));

Simulator::Run ();

// Calculate load balance factor

uint64_t maxLoad = 0;

uint64_t totalLoad = 0;

for (const auto &entry : nodePacketCounts)

{

uint64_t load = entry.second;

if (load > maxLoad)

{

maxLoad = load;

}

totalLoad += load;

}

double averageLoad = static_cast<double> (totalLoad) / nodes.GetN ();

double loadBalanceFactor = static_cast<double> (maxLoad) / averageLoad;

NS_LOG_UNCOND (“Max Load: ” << maxLoad);

NS_LOG_UNCOND (“Average Load: ” << averageLoad);

NS_LOG_UNCOND (“Load Balance Factor: ” << loadBalanceFactor);

// Clean up

Simulator::Destroy ();

return 0;

}

Explanation:

1. Setup Logging:
   • To track activities, enable logging for the UDP applications.
2. Create Nodes:
   • Create a set of nodes representing devices in the network.
3. Install Mobility Model:
   • On the nodes, install a mobility model (e.g., ConstantPositionMobilityModel).
4. Set Node Positions:
   • Set the positions of the nodes manually for simplicity.
5. Create Point-to-Point Links:
   • Install point-to-point links between the nodes.
6. Install Internet Stack:
   • On the nodes, install the Internet stack.
7. Assign IP Addresses:
   • To the network interfaces, assign IP addresses.
8. Install Applications:
   • On the nodes, install UDP server and client applications.
9. Trace Received Packets:
   • To trace received packets and log their counts for each node, Use a callback function.
10. Run Simulation:
    • Run the simulation for the specified duration.
11. Calculate Load Balance Factor:
    • After the simulation, calculate the maximum load and average load.
    • Calculate the load balance factor as the ratio of the maximum load to the average load.

Analyzing the Results:

• Max Load:
  • The maximum load on any node in terms of packet count.
• Average Load:
  • The average load across all nodes.
• Load Balance Factor:
  • The load balance factor hhh is calculated as the ratio of the maximum load to the average load.
  • A lower load balance factor indicates a more evenly distributed load across the network.

Totally, we had went through the calculation of network load balance factor hhh in ns3 by measuring the distribution of traffic across various nodes or links in the network. Also, we provide more topics related to Network load balance factor h.

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