To implement large-scale networks in ns3, we need to simulate a network with a large number of nodes, that can represent different network scenarios like large wireless networks, data centers, or IoT environments.
We have shared the complete guide to set up a large-scale network simulation in ns3.
Steps to implementation
- Set up your ns3
Make sure that ns3 is installed in the computer. If not, install it from the official ns3 website.
- Create a new ns3 script
On your ns3 installation, create a new C++ simulation script.
- Include necessary headers
Include all the required headers in the ns3 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/csma-module.h”
#include “ns3/mobility-module.h”
#include “ns3/applications-module.h”
#include “ns3/flow-monitor-module.h”
- Define the Network Topology
Create a basic network topology, that includes nodes, devices, and links. In our example, we will set up a large-scale CSMA (Ethernet) network.
using namespace ns3;
NS_LOG_COMPONENT_DEFINE (“LargeScaleNetworkExample”);
int main (int argc, char *argv[]) {
CommandLine cmd;
uint32_t numNodes = 1000;
cmd.AddValue (“numNodes”, “Number of nodes in the network”, numNodes);
cmd.Parse (argc, argv);
// Create nodes
NodeContainer nodes;
nodes.Create (numNodes);
// Set up CSMA (Ethernet) network
CsmaHelper csma;
csma.SetChannelAttribute (“DataRate”, StringValue (“1Gbps”));
csma.SetChannelAttribute (“Delay”, TimeValue (NanoSeconds (6560)));
NetDeviceContainer devices;
devices = csma.Install (nodes);
// 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);
// Set mobility
MobilityHelper mobility;
mobility.SetPositionAllocator (“ns3::GridPositionAllocator”,
“MinX”, DoubleValue (0.0),
“MinY”, DoubleValue (0.0),
“DeltaX”, DoubleValue (5.0),
“DeltaY”, DoubleValue (5.0),
“GridWidth”, UintegerValue (100),
“LayoutType”, StringValue (“RowFirst”));
mobility.SetMobilityModel (“ns3::ConstantPositionMobilityModel”);
mobility.Install (nodes);
// Install applications
uint16_t port = 9;
OnOffHelper onoff (“ns3::UdpSocketFactory”, InetSocketAddress (interfaces.GetAddress (numNodes – 1), port));
onoff.SetAttribute (“OnTime”, StringValue (“ns3::ConstantRandomVariable[Constant=1]”));
onoff.SetAttribute (“OffTime”, StringValue (“ns3::ConstantRandomVariable[Constant=0]”));
onoff.SetAttribute (“DataRate”, DataRateValue (DataRate (“50Mbps”)));
onoff.SetAttribute (“PacketSize”, UintegerValue (1024));
ApplicationContainer apps = onoff.Install (nodes.Get (0));
apps.Start (Seconds (1.0));
apps.Stop (Seconds (10.0));
PacketSinkHelper sink (“ns3::UdpSocketFactory”, InetSocketAddress (Ipv4Address::GetAny (), port));
ApplicationContainer sinkApps = sink.Install (nodes.Get (numNodes – 1));
sinkApps.Start (Seconds (0.0));
sinkApps.Stop (Seconds (10.0));
// Enable pcap tracing
csma.EnablePcap (“large-scale-network”, devices.Get (0), true);
// Set up flow monitor
FlowMonitorHelper flowmon;
Ptr<FlowMonitor> monitor = flowmon.InstallAll();
// Run simulation
Simulator::Stop (Seconds (10.0));
Simulator::Run ();
// Print flow monitor statistics
monitor->CheckForLostPackets ();
Ptr<Ipv4FlowClassifier> classifier = DynamicCast<Ipv4FlowClassifier> (flowmon.GetClassifier ());
std::map<FlowId, FlowMonitor::FlowStats> stats = monitor->GetFlowStats ();
for (std::map<FlowId, FlowMonitor::FlowStats>::const_iterator i = stats.begin (); i != stats.end (); ++i) {
Ipv4FlowClassifier::FiveTuple t = classifier->FindFlow (i->first);
NS_LOG_UNCOND (“Flow ” << i->first << ” (” << t.sourceAddress << ” -> ” << t.destinationAddress << “)”);
NS_LOG_UNCOND (” Tx Bytes: ” << i->second.txBytes);
NS_LOG_UNCOND (” Rx Bytes: ” << i->second.rxBytes);
NS_LOG_UNCOND (” Throughput: ” << i->second.rxBytes * 8.0 / (i->second.timeLastRxPacket.GetSeconds () – i->second.timeFirstTxPacket.GetSeconds ()) / 1024 << ” Kbps”);
}
Simulator::Destroy ();
return 0;
}
Explanation
- Network Topology: Sets up a large-scale CSMA network with a specified number of nodes.
- CSMA Setup: Use CsmaHelper to configure the CSMA network with a data rate of 1 Gbps and a delay of 6560 ns.
- Internet Stack: Use InternetStackHelper to install the IP stack on all nodes.
- Mobility: Use ConstantPositionMobilityModel to give nodes fixed positions in a grid layout.
- Applications: On the first node, an OnOff application is installed to generate UDP traffic to the last node. A PacketSink application is installed on the last node to receive the traffic.
- PCAP Tracing: Enable pcap to capture packets for analysis.
- Flow Monitor: Use FlowMonitorHelper to monitor network performance metrics such as throughput and packet loss.
- Build and Run the Script
Save the script and build it using the ns3 build system (waf).
./waf configure
./waf build
./waf –run large-scale-network
Extending the Example
We can extend this example by including more complex scenarios, such as:
- Wireless Networks: create large-scale wireless networks by using Wi-Fi or LTE modules.
- Dynamic Mobility Models: simulate node movement by using more advanced mobility models such as RandomWaypointMobilityModel or GaussMarkovMobilityModel.
- Routing Protocols: Use routing protocols like OLSR or AODV to handle multi-hop communication.
- Network Monitoring: Use the FlowMonitor module for monitoring additional network performance metrics such as delay, jitter, and packet loss.
- Energy Models: Include energy models to simulate battery consumption and energy-efficient communication protocols.
Here is an example of setting up a large-scale Wi-Fi network:
#include “ns3/wifi-module.h”
// In your main function, after creating the nodes
YansWifiChannelHelper wifiChannel = YansWifiChannelHelper::Default ();
YansWifiPhyHelper wifiPhy = YansWifiPhyHelper::Default ();
wifiPhy.SetChannel (wifiChannel.Create ());
WifiHelper wifi;
wifi.SetStandard (WIFI_STANDARD_80211n);
wifi.SetRemoteStationManager (“ns3::AarfWifiManager”);
WifiMacHelper wifiMac;
wifiMac.SetType (“ns3::AdhocWifiMac”);
NetDeviceContainer devices = wifi.Install (wifiPhy, wifiMac, nodes);
// Continue with the rest of the script
Overall, we had an analysis on the implementation of large scale networks using ns3 by simulating a network with a large number of nodes, which can represent a variety of network scenarios such as large wireless networks, data centers, or IoT environments.
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