To implement the task offloading decision in ns3 has needs to setup the network emulation and based on the certain conditions like CPU load, energy consumption, or network conditions have been measured then the tasks can be dynamically offloaded from one node to another. This procedure will cover how to setup up the network, generating traffic, and implementing a task offloading decision algorithm.
Step-by-step Implementation:
Step 1: Setup ns3 Environment
Make sure ns3 is installed in the system.
Step 2: Include Necessary Modules
Include the necessary ns3 modules in your script:
#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/energy-module.h”
#include “ns3/wifi-module.h”
#include “ns3/mobility-module.h”
Step 3: Create the Simulation Script
- Setup Nodes and Network:
using namespace ns3;
NS_LOG_COMPONENT_DEFINE (“TaskOffloadingSimulation”);
class OffloadingApplication : public Application
{
public:
OffloadingApplication ();
virtual ~OffloadingApplication ();
void Setup (Ptr<Socket> socket, Address address, uint32_t packetSize, uint32_t nPackets, DataRate dataRate);
void SetEnergySource (Ptr<BasicEnergySource> energySource);
void SetCpuLoad (double cpuLoad);
private:
virtual void StartApplication (void);
virtual void StopApplication (void);
void ScheduleTx (void);
void SendPacket (void);
void CheckOffloading (void);
Ptr<Socket> m_socket;
Address m_peer;
uint32_t m_packetSize;
uint32_t m_nPackets;
DataRate m_dataRate;
EventId m_sendEvent;
EventId m_offloadEvent;
bool m_running;
uint32_t m_packetsSent;
Ptr<BasicEnergySource> m_energySource;
double m_cpuLoad;
};
OffloadingApplication::OffloadingApplication ()
: m_socket (0),
m_peer (),
m_packetSize (0),
m_nPackets (0),
m_dataRate (0),
m_sendEvent (),
m_offloadEvent (),
m_running (false),
m_packetsSent (0),
m_energySource (0),
m_cpuLoad (0.0)
{
}
OffloadingApplication::~OffloadingApplication ()
{
m_socket = 0;
}
void
OffloadingApplication::Setup (Ptr<Socket> socket, Address address, uint32_t packetSize, uint32_t nPackets, DataRate dataRate)
{
m_socket = socket;
m_peer = address;
m_packetSize = packetSize;
m_nPackets = nPackets;
m_dataRate = dataRate;
}
void
OffloadingApplication::SetEnergySource (Ptr<BasicEnergySource> energySource)
{
m_energySource = energySource;
}
void
OffloadingApplication::SetCpuLoad (double cpuLoad)
{
m_cpuLoad = cpuLoad;
}
void
OffloadingApplication::StartApplication (void)
{
m_running = true;
m_packetsSent = 0;
m_socket->Bind ();
m_socket->Connect (m_peer);
SendPacket ();
ScheduleTx ();
m_offloadEvent = Simulator::Schedule (Seconds (1.0), &OffloadingApplication::CheckOffloading, this);
}
void
OffloadingApplication::StopApplication (void)
{
m_running = false;
if (m_sendEvent.IsRunning ())
{
Simulator::Cancel (m_sendEvent);
}
if (m_offloadEvent.IsRunning ())
{
Simulator::Cancel (m_offloadEvent);
}
if (m_socket)
{
m_socket->Close ();
}
}
void
OffloadingApplication::SendPacket (void)
{
Ptr<Packet> packet = Create<Packet> (m_packetSize);
m_socket->Send (packet);
if (++m_packetsSent < m_nPackets)
{
ScheduleTx ();
}
}
void
OffloadingApplication::ScheduleTx (void)
{
if (m_running)
{
Time tNext (Seconds (m_packetSize * 8 / static_cast<double> (m_dataRate.GetBitRate ())));
m_sendEvent = Simulator::Schedule (tNext, &OffloadingApplication::SendPacket, this);
}
}
void
OffloadingApplication::CheckOffloading (void)
{
if (m_energySource && m_cpuLoad > 0.8)
{
double remainingEnergy = m_energySource->GetRemainingEnergy ();
if (remainingEnergy < 20.0)
{
NS_LOG_UNCOND (“Offloading task from node due to low energy and high CPU load”);
// Implement offloading logic here
}
}
if (m_running)
{
m_offloadEvent = Simulator::Schedule (Seconds (1.0), &OffloadingApplication::CheckOffloading, this);
}
}
int main (int argc, char *argv[])
{
CommandLine cmd;
cmd.Parse (argc, argv);
// Create nodes
NodeContainer nodes;
nodes.Create (4);
// Create point-to-point links
PointToPointHelper pointToPoint;
pointToPoint.SetDeviceAttribute (“DataRate”, StringValue (“5Mbps”));
pointToPoint.SetChannelAttribute (“Delay”, StringValue (“2ms”));
NetDeviceContainer devices;
devices = pointToPoint.Install (nodes.Get (0), nodes.Get (1));
devices = pointToPoint.Install (nodes.Get (1), nodes.Get (2));
devices = pointToPoint.Install (nodes.Get (2), nodes.Get (3));
// Install Internet stack
InternetStackHelper stack;
stack.Install (nodes);
// Assign IP addresses
Ipv4AddressHelper address;
address.SetBase (“10.1.1.0”, “255.255.255.0”);
Ipv4InterfaceContainer interfaces = address.Assign (devices);
// Set up energy model
BasicEnergySourceHelper basicSourceHelper;
basicSourceHelper.Set (“BasicEnergySourceInitialEnergyJ”, DoubleValue (100.0));
EnergySourceContainer sources = basicSourceHelper.Install (nodes);
WifiRadioEnergyModelHelper radioEnergyHelper;
radioEnergyHelper.Set (“TxCurrentA”, DoubleValue (0.0174));
radioEnergyHelper.Set (“RxCurrentA”, DoubleValue (0.0197));
DeviceEnergyModelContainer deviceModels = radioEnergyHelper.Install (devices, sources);
// Set up applications
TypeId tid = TypeId::LookupByName (“ns3::UdpSocketFactory”);
Ptr<Socket> recvSink = Socket::CreateSocket (nodes.Get (3), tid);
InetSocketAddress local = InetSocketAddress (Ipv4Address::GetAny (), 80);
recvSink->Bind (local);
recvSink->SetRecvCallback (MakeCallback (&LogPacketReceive));
Ptr<Socket> source = Socket::CreateSocket (nodes.Get (0), tid);
InetSocketAddress remote = InetSocketAddress (interfaces.GetAddress (3), 80);
source->Connect (remote);
Ptr<OffloadingApplication> app = CreateObject<OffloadingApplication> ();
app->Setup (source, remote, 1024, 100, DataRate (“1Mbps”));
app->SetEnergySource (sources.Get (0));
app->SetCpuLoad (0.9); // Set initial CPU load
nodes.Get (0)->AddApplication (app);
app->SetStartTime (Seconds (1.0));
app->SetStopTime (Seconds (10.0));
Simulator::Stop (Seconds (10.0));
Simulator::Run ();
Simulator::Destroy ();
return 0;
}
Log Packet Receive: Implement the callback function to handle the reception of packets.
void LogPacketReceive (Ptr<Socket> socket)
{
Ptr<Packet> packet;
Address from;
while ((packet = socket->RecvFrom (from)))
{
NS_LOG_UNCOND (“Packet received at ” << Simulator::Now ().GetSeconds () << ” from ” << address);
}
}
Step 4: Run the Simulation
Compile and run your simulation script:
./waf configure
./waf build
./waf –run TaskOffloadingSimulation
Explanation
- Node Creation: Create nodes representing different devices in the network.
- Point-to-Point Links: Configure point-to-point links between nodes.
- Internet Stack: Install the Internet stack on all nodes.
- IP Configuration: Assign IP addresses to the nodes.
- Energy Model: Install an energy model on the nodes to simulate energy consumption.
- Applications: Use a custom OffloadingApplication that sends packets and logs received packets. The application also checks the energy levels and CPU load to decide whether to offload tasks.
- Logging: Implement a function to log packet reception events.
- Task Offloading Decision: Implement logic in the CheckOffloading function to make offloading decisions based on energy levels and CPU load.
Advanced Task Offloading Techniques
- Load-Based Offloading: Implement offloading based on node load (e.g., CPU usage or network traffic).
if (m_cpuLoad > 0.8) // Example condition for high CPU load
{
NS_LOG_UNCOND (“Offloading task from node due to high CPU load”);
// Implement offloading logic here
}
Network Condition-Based Offloading: Offload tasks based on network conditions like latency or bandwidth.
double networkLatency = …; // Implement logic to measure network latency
if (networkLatency > 100.0) // Example condition for high network latency
{
NS_LOG_UNCOND (“Offloading task from node due to high network latency”);
// Implement offloading logic here
}
Monitoring and Adaptation: Implement monitoring to adaptively manage task offloading.
void MonitorNetworkConditions ()
{
// Implement logic to monitor network conditions
double currentLatency = …; // Measure current network latency
double currentBandwidth = …; // Measure current network bandwidth
// Adapt task offloading based on monitored conditions
if (currentLatency > thresholdLatency || currentBandwidth < thresholdBandwidth)
{
NS_LOG_UNCOND (“Offloading task due to network condition”);
// Implement offloading logic here
}
Simulator::Schedule (Seconds (1.0), &MonitorNetworkConditions);
}
As a final point, we discussed about how to implement and process the task offloading decision in ns3 tool clearly. We also provide all kinds of task offloading decision information how it adjust in various environments.
ns3simulation.com conduct comparative analyses in networking and share a range of project topics associated with Task Offloading Decision using the ns3 tool, along with implementation support get in touch with us for more benefit.