To implement network resource allocation in ns3, we need to set-up a simulation. In this simulation based on certain criteria, the resources like bandwidth and power that has to be dynamically allocated to different nodes or applications. This application will be typically useful for simulating scenarios like bandwidth allocation in cellular networks, power control in wireless networks, or dynamic quality of service (QoS) management. The following steps will guide creating a basic simulation with network resource allocation in ns3:
Step-by-step guide to implement Network resource allocation
- Set Up ns3 Environment
Make sure ns3 is installed on the system.
- Create a New Simulation Script
Create a new C++ script for simulation. For this example, we will use C++.
- Include Necessary Headers
Include the necessary ns3 headers in the 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/flow-monitor-module.h”
#include “ns3/qos-wifi-mac-helper.h”
#include “ns3/yans-wifi-helper.h”
#include “ns3/ssid.h”
4. Define the Network Topology
Set up the basic network topology, including nodes, devices, and links.
using namespace ns3;
NS_LOG_COMPONENT_DEFINE (“ResourceAllocationExample”);
void AllocateResources (Ptr<NetDevice> device, DataRate dataRate) {
device->GetObject<PointToPointNetDevice> ()->SetDataRate (dataRate);
NS_LOG_UNCOND (“Allocated ” << dataRate.GetBitRate () << ” bps to ” << device->GetNode ()->GetId ());
}
int main (int argc, char *argv[]) {
CommandLine cmd;
cmd.Parse (argc, argv);
// Create nodes
NodeContainer nodes;
nodes.Create (4); // 4 nodes: 2 for one link, 2 for another
// Set up 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));
NetDeviceContainer devices2;
devices2 = pointToPoint.Install (nodes.Get (2), nodes.Get (3));
// Install the internet stack
InternetStackHelper stack;
stack.Install (nodes);
Ipv4AddressHelper address;
address.SetBase (“10.1.1.0”, “255.255.255.0”);
Ipv4InterfaceContainer interfaces = address.Assign (devices);
address.SetBase (“10.1.2.0”, “255.255.255.0”);
Ipv4InterfaceContainer interfaces2 = address.Assign (devices2);
// Set up applications
uint16_t port = 9; // Discard port
UdpServerHelper server (port);
ApplicationContainer serverApp = server.Install (nodes.Get (1));
serverApp.Start (Seconds (1.0));
serverApp.Stop (Seconds (10.0));
UdpClientHelper client (interfaces.GetAddress (1), port);
client.SetAttribute (“MaxPackets”, UintegerValue (320));
client.SetAttribute (“Interval”, TimeValue (Seconds (0.05)));
client.SetAttribute (“PacketSize”, UintegerValue (1024));
ApplicationContainer clientApp = client.Install (nodes.Get (0));
clientApp.Start (Seconds (2.0));
clientApp.Stop (Seconds (10.0));
UdpServerHelper server2 (port);
ApplicationContainer serverApp2 = server2.Install (nodes.Get (3));
serverApp2.Start (Seconds (1.0));
serverApp2.Stop (Seconds (10.0));
UdpClientHelper client2 (interfaces2.GetAddress (1), port);
client2.SetAttribute (“MaxPackets”, UintegerValue (320));
client2.SetAttribute (“Interval”, TimeValue (Seconds (0.05)));
client2.SetAttribute (“PacketSize”, UintegerValue (1024));
ApplicationContainer clientApp2 = client2.Install (nodes.Get (2));
clientApp2.Start (Seconds (2.0));
clientApp2.Stop (Seconds (10.0));
// Enable pcap tracing
pointToPoint.EnablePcapAll (“resource-allocation”);
// Schedule resource allocation
Simulator::Schedule (Seconds (3.0), &AllocateResources, devices.Get (0), DataRate (“10Mbps”));
Simulator::Schedule (Seconds (5.0), &AllocateResources, devices2.Get (0), DataRate (“1Mbps”));
// Run simulation
Simulator::Stop (Seconds (10.0));
Simulator::Run ();
Simulator::Destroy ();
return 0;
}
Explanation
- Network Topology: The script sets up two point-to-point links between four nodes.
- Applications: UDP servers are installed on the receiving nodes, and UDP clients are installed on the sending nodes to generate traffic.
- PCAP Tracing: PCAP tracing is enabled to capture packets for analysis.
- Resource Allocation: The AllocateResources function dynamically changes the data rate of the point-to-point link during the simulation. This function is scheduled to run at specific times to allocate different data rates to the links.
5. Build and Run the Script
Save the script and build it using the ns3 build system (waf).
./waf configure
./waf build
./waf –run resource-allocation
Extending the Example
This example can be extended to include more complex resource allocation schemes, such as:
- Dynamic Bandwidth Allocation: Adjust the data rate based on network conditions, traffic demand, or QoS requirements.
- Power Control: Adjust the transmission power of wireless devices to manage interference and save energy.
- Priority-Based Allocation: Based on the priority of the traffic or applications allocate the resources.
An example of dynamic resource allocation based on traffic demand has given below:
void DynamicResourceAllocation (Ptr<NetDevice> device) {
Ptr<PointToPointNetDevice> p2pDevice = device->GetObject<PointToPointNetDevice> ();
uint32_t currentQueueSize = p2pDevice->GetQueue ()->GetNPackets ();
if (currentQueueSize > 10) {
p2pDevice->SetDataRate (DataRate (“10Mbps”));
} else {
p2pDevice->SetDataRate (DataRate (“5Mbps”));
}
NS_LOG_UNCOND (“Queue size: ” << currentQueueSize << “, Data rate: ” << p2pDevice->GetDataRate ().GetBitRate () << ” bps”);
// Schedule the next check
Simulator::Schedule (Seconds (1.0), &DynamicResourceAllocation, device);
}
// Schedule the dynamic resource allocation
Simulator::Schedule (Seconds (2.0), &DynamicResourceAllocation, devices.Get (0));
At last, we have concluded that network resource allocation can be implemented in ns3 using resources under certain criteria and also it can extend to include more complex resource allocation schemes using dynamic bandwidth allocation, power control, priority-based allocation.
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