How to Simulate Low Latency Communication Projects Using NS3

To simulate Low Latency Communication projects in NS3 has concentrates on reducing the end-to-end latency in data transmission that is critical in applications like real-time communications, industrial automation, autonomous vehicles, and augmented/virtual reality (AR/VR).

Here’s how you can simulate such a scenario:

Steps to Simulate Low Latency Communication in NS3

  1. Install NS3:

Initiate by installing NS3 by following the NS3 installation guide.

  1. Understand Low Latency Communication:

Low latency is essential in scenarios in which real-time response is critical. The primary goals have contained to reduce:

  • Propagation delay: The time it takes for data to travel across the network.
  • Transmission delay: The time it takes to push all the bits onto the transmission medium.
  • Queuing delay: The time data spends waiting in queues.
  • Processing delay: The time to process the data.
  1. Set Up the Simulation Environment:
  • Create nodes signify devices such as users, servers, sensors that will interact in a low-latency setup.
  • Install communication protocols: Utilize technologies such as Wi-Fi, LTE, or Ethernet, rely on the type of network that need to simulate such as 5G, real-time industrial networks.
  1. Use High-Speed Networking Technologies:
  • LTE/5G: Use LteHelper to replicate high-speed mobile networks that needs low latency.
  • Wi-Fi: Use WifiHelper to replicate low-latency wireless communication.
  • Ethernet: Utilize CsmaHelper to replicate low-latency wired connections, that can be helpful in industrial or data centre environments.

Example for using LTE:

LteHelper lteHelper;

NodeContainer enbNodes;

NodeContainer ueNodes;

enbNodes.Create (1); // eNodeB node

ueNodes.Create (4);  // User Equipment (UE) nodes

NetDeviceContainer enbDevs = lteHelper.InstallEnbDevice (enbNodes);

NetDeviceContainer ueDevs = lteHelper.InstallUeDevice (ueNodes);

// Attach UEs to the eNodeB

lteHelper.Attach (ueDevs, enbDevs.Get (0));

Example for using Wi-Fi:

WifiHelper wifi;

YansWifiChannelHelper channel = YansWifiChannelHelper::Default ();

YansWifiPhyHelper phy = YansWifiPhyHelper::Default ();

phy.SetChannel (channel.Create ());

WifiMacHelper mac;

mac.SetType (“ns3::AdhocWifiMac”);

NodeContainer wifiNodes;

wifiNodes.Create (4); // 4 nodes in the network

NetDeviceContainer devices = wifi.Install (phy, mac, wifiNodes);

  1. Traffic Generation with Low Latency Requirements:

To replicate low-latency applications, utilize OnOffApplication, UdpEchoClient, or UdpServer to generate real-time traffic. These applications can create continuous or bursty traffic with strict delay constraints.

Example of UDP Echo Communication:

UdpEchoServerHelper echoServer (9);

ApplicationContainer serverApps = echoServer.Install (nodes.Get (0)); // Server node

serverApps.Start (Seconds (1.0));

serverApps.Stop (Seconds (10.0));

UdpEchoClientHelper echoClient (interfaces.GetAddress (0), 9);

echoClient.SetAttribute (“MaxPackets”, UintegerValue (1000));

echoClient.SetAttribute (“Interval”, TimeValue (Seconds (0.001))); // Interval for low latency

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

ApplicationContainer clientApps = echoClient.Install (nodes.Get (1)); // Client node

clientApps.Start (Seconds (2.0));

clientApps.Stop (Seconds (10.0));

  1. Network Configuration for Low Latency:
  • Set Low Latency Parameters:
    • Data Rate: Use high data rates to make sure fast transmission of data.
    • Delay Model: Utilize low propagation delay models.
    • Queue Sizes: Limit buffer sizes to avoid queuing delays.

Example for setting a low delay channel:

PointToPointHelper pointToPoint;

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

pointToPoint.SetChannelAttribute (“Delay”, StringValue (“1ms”)); // Low delay link

  1. Optimize Queue Management:

In low-latency networks, controlling queuing delay is essential. Utilize queue management approaches to reduce queuing delays:

  • Tail Drop Queuing: This is the default queue management approch but can lead to higher delays when queues get full.
  • Active Queue Management (AQM): Approaches such as RED (Random Early Detection) can support to handle queues better to prevent latency issues.

Example of configuring a queue:

PointToPointHelper p2p;

p2p.SetQueue (“ns3::DropTailQueue”, “MaxPackets”, UintegerValue (5)); // Small queue for low latency

  1. Mobility Models for Real-Time Low Latency Applications:

For scenarios like autonomous driving or UAV-based communication, utilize mobility models such as ConstantPositionMobilityModel or RandomWalk2dMobilityModel to emulate movement while making sure that low-latency communication remains unaffected.

MobilityHelper mobility;

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

mobility.Install (nodes);

  1. Evaluate and Measure Latency:
  • End-to-End Delay: Evaluate the time it takes for packets to send from the sender to the receiver.
  • Jitter: Evaluate the variability in packet arrival times (significant in real-time applications).
  • Packet Loss: Make sure reliable data delivery while maintaining low latency.

We can utilize FlowMonitor to evaluate these parameters and measure the performance of low-latency communication.

Example for measuring latency:

FlowMonitorHelper flowmon;

Ptr<FlowMonitor> monitor = flowmon.InstallAll ();

Simulator::Stop (Seconds (10.0));

Simulator::Run ();

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);

std::cout << “Flow ” << i->first << ” (” << t.sourceAddress << ” -> ” << t.destinationAddress << “)\n”;

std::cout << ”  Tx Bytes: ” << i->second.txBytes << “\n”;

std::cout << ”  Rx Bytes: ” << i->second.rxBytes << “\n”;

std::cout << ”  Delay: ” << i->second.delaySum.GetSeconds () / i->second.rxPackets << ” s\n”;

}

Simulator::Destroy ();

  1. Advanced Features for Ultra-Low Latency:
  • Edge Computing: Replicate offloading data processing to edge nodes (closer to the user), minimizing the time spent in data transmission.
  • 5G NR (New Radio): Utilize the mmWave module in NS3 for replicating 5G networks, which are intended to support ultra-low latency communication.
  • Time-Sensitive Networking (TSN): Execute TSN protocols to ensure deterministic low-latency communication, particularly in industrial applications.

Example Code Snippet for Low Latency Communication:

#include “ns3/core-module.h”

#include “ns3/network-module.h”

#include “ns3/internet-module.h”

#include “ns3/point-to-point-module.h”

#include “ns3/udp-echo-helper.h”

#include “ns3/flow-monitor-module.h”

using namespace ns3;

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

{

NodeContainer nodes;

nodes.Create (2);

PointToPointHelper pointToPoint;

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

pointToPoint.SetChannelAttribute (“Delay”, StringValue (“1ms”)); // Low delay link

NetDeviceContainer devices;

devices = pointToPoint.Install (nodes);

InternetStackHelper stack;

stack.Install (nodes);

Ipv4AddressHelper address;

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

Ipv4InterfaceContainer interfaces = address.Assign (devices);

UdpEchoServerHelper echoServer (9);

ApplicationContainer serverApps = echoServer.Install (nodes.Get (1));

serverApps.Start (Seconds (1.0));

serverApps.Stop (Seconds (10.0));

UdpEchoClientHelper echoClient (interfaces.GetAddress (1), 9);

echoClient.SetAttribute (“MaxPackets”, UintegerValue (1000));

echoClient.SetAttribute (“Interval”, TimeValue (Seconds (0.001))); // Low latency interval

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

ApplicationContainer clientApps = echoClient.Install (nodes.Get (0));

clientApps.Start (Seconds (2.0));

clientApps.Stop (Seconds (10.0));

// Flow monitor to track performance

FlowMonitorHelper flowmon;

Ptr<FlowMonitor> monitor = flowmon.InstallAll ();

Simulator::Run ();

monitor->CheckForLostPackets ();

monitor->SerializeToXmlFile(“flow-monitor.xml”, true, true);

Simulator::Destroy ();

return 0;

}

Advanced Optimization Tips:

  • Optimize Packet Sizes: Choose smaller packet sizes to minimize transmission delay.
  • Reduce Queue Lengths: Reduce buffer lengths to mitigate queuing delays.
  • Use Fast Transmission Technologies: Utilize fast transmission rates and low-delay links to make sure ultra-low latency.

In the end of the simulation, we all learn and get knowledge about the Low Latency Communication that is used to minimize the end to end latency during transmission was implemented in ns3 simulation tool. We will elaborate on the Low Latency Communication strategy applied in different simulation instances in further manual.

Experience the power of NS3 for your projects by simulating low latency communication. Share your research details with us, and we’ll offer tailored solutions to assist you in evaluating performance effectively.

 

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