To begin executing low-latency communication using NS3, we want to model and set up a network simulation for reducing interaction duration among the nodes. It is essential for real-time applications such as autonomous vehicles, industrial automation, online gaming, and telemedicine. The given below is a brief procedure on how to start:

Steps to Begin Implement a Low Latency Communication in NS3

1. Set Up ns3 Environment

1. Install ns3:
   • We should download and install the latest version of ns3 on the machine.
   • Make sure that installation properly with execute a simple example script as ./waf –run hello-simulator.
2. Ensure Required Modules:
   • It has necessary modules like point-to-point, wifi, lte, or any other components according to the interaction medium.

2. Define Objectives

Decide on the projects objectives of low-latency communication:

• Reduce end-to-end delay.
• Make certain reliable interaction.
• Sustain throughput and packet delivery ratio.

3. Select Communication Medium

Select the suitable technology for the applications:

• Wired (e.g., Point-to-Point Links):
  • It is used for deterministic and minimal latency.
• Wireless (e.g., Wi-Fi, LTE, or 5G):
  • For adaptable and mobile networks.

4. Configure the Network Topology

1. Create Nodes:
   • Make nodes to denote the devices utilising NodeContainer.

NodeContainer nodes;

nodes.Create(2); // Two nodes for simple communication

1. Set Up Connectivity:
   • Point-to-Point (Wired):

PointToPointHelper p2p;

p2p.SetDeviceAttribute(“DataRate”, StringValue(“10Gbps”));

p2p.SetChannelAttribute(“Delay”, StringValue(“1ms”));

NetDeviceContainer devices = p2p.Install(nodes);

1. • Wireless (Wi-Fi):

WifiHelper wifi;

wifi.SetStandard(WIFI_PHY_STANDARD_80211n);

YansWifiPhyHelper phy = YansWifiPhyHelper::Default();

YansWifiChannelHelper channel = YansWifiChannelHelper::Default();

phy.SetChannel(channel.Create());

WifiMacHelper mac;

mac.SetType(“ns3::AdhocWifiMac”);

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

1. Assign IP Addresses:

InternetStackHelper internet;

internet.Install(nodes);

Ipv4AddressHelper ipv4;

ipv4.SetBase(“10.1.1.0”, “255.255.255.0”);

Ipv4InterfaceContainer interfaces = ipv4.Assign(devices);

5. Install Low-Latency Applications

1. UDP for Real-Time Traffic:
   • Prevent overhead of TCP retransmissions in real-time traffic using UDP.

Example:

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(100));

echoClient.SetAttribute(“Interval”, TimeValue(Seconds(0.01))); // 10 ms interval

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

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

clientApps.Start(Seconds(2.0));

clientApps.Stop(Seconds(10.0));

1. Custom Low-Latency Application:
   • Create a custom application as certain behavior is required.

class LowLatencyApp : public Application {

public:

void StartApplication() override {

// Custom logic for sending/receiving low-latency data

}

};

6. Implement QoS Mechanisms

Below is an advanced enhancement of low latency:

1. Prioritize Traffic:
   • Give precedence to low-latency traffic to apply DiffServ or other QoS approaches.
   • Example: Configure DSCP (Differentiated Services Code Point) within packet headers.
2. Optimize Packet Size:
   • Smaller packets supports to minimize the serialization delay.
3. Adjust Queues:
   • Set queue sizes for preventing bufferbloat.

Config::SetDefault(“ns3::DropTailQueue<Packet>::MaxSize”, StringValue(“50p”));

7. Simulate and Analyze Performance

1. Run the Simulation:
   • Now, we can compile and then execute the simulation script as ./waf.
   • For instance, ./waf –run “scratch/low-latency”
2. Measure Latency:
   • Seize delay of packet that effectively transmit and receive events with the support of trace files or records.

Example:

Simulator::Schedule(Seconds(1.0), &TraceLatency);

1. Log Results:
   • For in-depth packet-level event logging to leverage NS_LOG.

8. Visualize and Optimize

1. Visualization:
   • Make use of NetAnim to envision packet flows and node communications.

AnimationInterface anim(“low-latency.xml”);

1. Optimization:
   • Test with:
     • Minimizing queue sizes.
     • To maximizing link speeds.
     • Adapting application-layer metrics such as interval, packet size.

9. Extend the Implementation

1. Multi-Hop Scenarios:
   • Experiment latency within a more complex topology including intermediate nodes.
2. Dynamic Traffic:
   • Replicate diverse dynamic traffic loads and then estimate the latency.
3. Advanced Techniques:
   • Experiment the Machine Learning models to enhance the metrics dynamically for low latency.

Example Use Cases

• Real-Time Video: This low latency communication utilises for streaming video with minimal buffering.
• Autonomous Vehicles: Rapid interaction among the vehicles and infrastructure.
• Online Gaming: To make sure real-time interactivity in online gaming.

We successfully developed implementation steps for executing, evaluating and analysing the Low Latency Communication projects in NS3 environment. We’re ready to offer further extension on this subject upon request.