How to Begin Implement Network Mean Opinion Score in NS3

To implement the Mean Opinion Score (MOS) in ns-3 has involves calculate the amount of user experience in multimedia or voice application. MOS is the subjective metric derived from objective network parameters metrices such as delay, jitter, and packet loss, and it typically ranges from 1 (bad) to 5 (excellent).

Here’s a step-by-step guide to implementing MOS in ns-3:

Steps to Begin Implement Network Mean Opinion Score in NS3

1. Understand Mean Opinion Score (MOS)

• MOS Definition:
  • The metric used to amount of perceived quality for multimedia or voice transmission.
• Factors Affecting MOS:
  • Latency (Delay): Decrease the higher delay for user satisfaction.
  • Jitter: Impact of playback smoothness for variability in delay.
  • Packet Loss: It stopped the packets can be reducing the quality significantly.
• Common Applications:
  • Online gaming.
  • VoIP (Voice over IP).
  • Video streaming.

2. Set up ns-3 Environment

• Install ns-3:

git clone https://gitlab.com/nsnam/ns-3-dev.git

cd ns-3-dev

./ns3 configure –enable-examples –enable-tests

./ns3 build

• Validate the installation:

./ns3 run hello-simulator

3. Design the Network Simulation

• Scenario:
  • It replicate a multimedia application for instance VoIP or video streaming.
  • Estimate the delay, jitter, and packet loss.
  • Use these metrics for calculate this MOS.
• Topology:
  • Sender: Makes congestion for multimedia.
  • Receiver: Calculates the received congestion and computes MOS.
  • Intermediate Nodes: It stimulates the network environments such as congestion or loss.

4. Steps toImplement MOS

(a) Create Nodes

• Describe the sender and receiver nodes:

NodeContainer sender, receiver;

sender.Create(1);

receiver.Create(1);

(b) Set Up Network Links

• Used for linked the nodes PointToPointHelper:

PointToPointHelper p2p;

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

p2p.SetChannelAttribute(“Delay”, StringValue(“2ms”));

NetDeviceContainer devices = p2p.Install(NodeContainer(sender.Get(0), receiver.Get(0)));

(c) Install Internet Stack

• Install for all nodes in the Internet stack:

InternetStackHelper stack;

stack.Install(sender);

stack.Install(receiver);

(d) Assign IP Addresses

• Allocate the IP addresses for the devices:

Ipv4AddressHelper address;

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

address.Assign(devices);

5. Simulate Multimedia Traffic

• Use an application such as UDP Echo or a custom application for replicate the multimedia congestion.

Sender (Traffic Generator):

UdpEchoServerHelper echoServer(9);

ApplicationContainer serverApp = echoServer.Install(sender.Get(0));

serverApp.Start(Seconds(1.0));

serverApp.Stop(Seconds(10.0));

Receiver (Traffic Receiver):

UdpEchoClientHelper echoClient(Ipv4Address(“10.1.1.1”), 9);

echoClient.SetAttribute(“MaxPackets”, UintegerValue(100));

echoClient.SetAttribute(“Interval”, TimeValue(Seconds(0.1)));

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

ApplicationContainer clientApp = echoClient.Install(receiver.Get(0));

clientApp.Start(Seconds(2.0));

clientApp.Stop(Seconds(10.0));

6. Measure Network Metrics

(a) Measure Delay

• Seizure the transmission and reception times:

void MeasureDelay(Ptr<const Packet> packet, Time txTime) {

Time delay = Simulator::Now() – txTime;

NS_LOG_UNCOND(“Packet delay: ” << delay.GetSeconds() << ” seconds”);

}

(b) Measure Jitter

• Estimate the jitter as the variation in delay:

static Time lastDelay = Seconds(0);

void MeasureJitter(Ptr<const Packet> packet, Time txTime) {

Time delay = Simulator::Now() – txTime;

Time jitter = std::abs((delay – lastDelay).GetSeconds());

lastDelay = delay;

NS_LOG_UNCOND(“Packet jitter: ” << jitter.GetSeconds() << ” seconds”);

}

(c) Measure Packet Loss

• Amount of transmitted and received packets loss for computed:

static uint32_t sentPackets = 0, receivedPackets = 0;

void IncrementSentPackets() {

sentPackets++;

}

void IncrementReceivedPackets() {

receivedPackets++;

}

double CalculatePacketLoss() {

return 1.0 – (double)receivedPackets / (double)sentPackets;

}

7. Compute MOS

• Use the empirical method to measure the MOS based on delay, jitter, and packet loss:

double ComputeMOS(double delay, double jitter, double packetLoss) {

double mos = 1.0 + 4.0 * exp(-0.1 * (delay + jitter)) * pow(1.0 – packetLoss, 2);

return std::min(std::max(mos, 1.0), 5.0); // Clamp MOS to [1, 5]

}

8. Complete Example Code

Under is an sample for executes the MOS calculation:

#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”

using namespace ns3;

static uint32_t sentPackets = 0, receivedPackets = 0;

static Time lastDelay = Seconds(0);

void IncrementSentPackets() {

sentPackets++;

}

void MeasureDelayAndJitter(Ptr<const Packet> packet, Time txTime) {

Time delay = Simulator::Now() – txTime;

Time jitter = std::abs((delay – lastDelay).GetSeconds());

lastDelay = delay;

receivedPackets++;

NS_LOG_UNCOND(“Packet delay: ” << delay.GetSeconds() << ” seconds”);

NS_LOG_UNCOND(“Packet jitter: ” << jitter.GetSeconds() << ” seconds”);

}

double CalculatePacketLoss() {

return 1.0 – (double)receivedPackets / (double)sentPackets;

}

double ComputeMOS(double delay, double jitter, double packetLoss) {

double mos = 1.0 + 4.0 * exp(-0.1 * (delay + jitter)) * pow(1.0 – packetLoss, 2);

return std::min(std::max(mos, 1.0), 5.0);

}

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

CommandLine cmd;

cmd.Parse(argc, argv);

NodeContainer sender, receiver;

sender.Create(1);

receiver.Create(1);

PointToPointHelper p2p;

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

p2p.SetChannelAttribute(“Delay”, StringValue(“2ms”));

NetDeviceContainer devices = p2p.Install(NodeContainer(sender.Get(0), receiver.Get(0)));

InternetStackHelper stack;

stack.Install(sender);

stack.Install(receiver);

Ipv4AddressHelper address;

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

address.Assign(devices);

UdpEchoServerHelper echoServer(9);

ApplicationContainer serverApp = echoServer.Install(sender.Get(0));

serverApp.Start(Seconds(1.0));

serverApp.Stop(Seconds(10.0));

UdpEchoClientHelper echoClient(Ipv4Address(“10.1.1.1”), 9);

echoClient.SetAttribute(“MaxPackets”, UintegerValue(100));

echoClient.SetAttribute(“Interval”, TimeValue(Seconds(0.1)));

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

ApplicationContainer clientApp = echoClient.Install(receiver.Get(0));

clientApp.Start(Seconds(2.0));

clientApp.Stop(Seconds(10.0));

// Attach callbacks

devices.Get(0)->TraceConnectWithoutContext(“Tx”, MakeCallback(&IncrementSentPackets));

devices.Get(1)->TraceConnectWithoutContext(“PhyRxEnd”, MakeCallback(&MeasureDelayAndJitter));

Simulator::Run();

// Calculate MOS

double packetLoss = CalculatePacketLoss();

double mos = ComputeMOS(0.2, 0.05, packetLoss); // Example: Average delay=0.2s, jitter=0.05s

NS_LOG_UNCOND(“Mean Opinion Score (MOS): ” << mos);

Simulator::Destroy();

return 0;

}

9. Validate and Extend

• Validation:
  • Examine the records logs for MOS values to assure the accurate computation.
• Extensions:
  • It replicates the various congestion conditions for instance congestion, high packet loss.
  • Enhance the further advanced MOS procedures for sample E-model for VoIP.

In this module, we had successfully calculated and implement the mean option score in the network using ns3. If you have concerns or queries, they will be addressed in a separate manual.