Difference between revisions of "Ns-3-Network-Simulator/C3/Infrastructure-based-Wireless-Network/English"

Learning Objectives

• Create an infrastructure based wireless network.
• Create three UDP flows in the channels.
• Analyze the flow using a flow monitor.
• Visualize the network using NetAnim.

System Requirements

• Ubuntu Linux OS version 22.04.
• ns-3 version 3.38.
• NetAnim visualizer tool.

Pre-requisites

• The learner must have basic knowledge of ns-3 software
• For pre-requisite ns-3 tutorials, please visit this website https://spoken-tutorial.org

Code Files

• The files used in this tutorial are provided in theCode files link.
• Please download and extract the files.
• Make a copy and then use them while practicing.

Infrastructure based Wifi network

In this diagram, the nodes 0, 2 and 3 are station nodes.

Node 1 is the access point of the infrastructure.

About DSSS

It uses Direct Sequence Spread Spectrum modulation.

In a DSSS system, data is spread over a wider bandwidth using a spreading code.

About DSSS

DSSS rate represents the speed of information transmitted after spreading.

DSSS can transfer up to 11 Mbps of data.

The source code contains the required functions to create an infrastructure based wireless network.

Now we will go through the source code in the text editor.

uint32_t numPackets = 100;

Then we’ll set the number of packets to be transmitted as 100.

uint32_t sourceNode = 0;

Non-unicast mode means that the data may be sent from one node to many nodes.

c.Create(4);

if (verbose) { WifiHelper::EnableLogComponents(); } wifi.SetStandard(WIFI_STANDARD_80211b);

For that, let us use the WifiHelper class.

Using Wifi-helper class, we enable logging components and set the wifi standard.

Here, the standard set is IEEE 802.11b.

wifiPhy.Set("RxGain", DoubleValue(0));

RxGain is used to adjust the sensitivity of the receiving signal.

wifiChannel.SetPropagationDelay("ns3::ConstantSpeedPropagationDelayModel");

wifiChannel.AddPropagationLoss("ns3::FixedRssLossModel", "Rss", DoubleValue(rss));

Let us set the Propagation delay and add the propagation loss to our model.

wifi.SetRemoteStationManager("ns3::ConstantRateWifiManager","DataMode", StringValue(phyMode), "ControlMode", StringValue(phyMode));

Then we set a constant rate for data and control modes of wifi stations.

SSID or Service Set Identifier is a sequence of characters uniquely identifying a network.

NetDeviceContainer staDevice = wifi.Install(wifiPhy, wifiMac, c);

NetDeviceContainer devices = staDevice;

We create a container staDevice to hold the installed Wifi devices.

As a next step, we shall take a copy of staDevice container in devices container.

wifiMac.SetType("ns3::ApWifiMac", "Ssid", SsidValue(ssid));

NetDeviceContainer apDevice = wifi.Install(wifiPhy, wifiMac, c.Get(1));

devices.Add(apDevice);

We have set up the AP node of the wireless network using ApWifiMac protocol.

We are also installing wifiphy to the node1 of the wireless network.

Then ssid is assigned to the AP node of the network.

Ptr<ListPositionAllocator> positionAlloc = CreateObject<ListPositionAllocator>();

positionAlloc->Add(Vector(3.0, 4.0, 3.0));

mobility.SetPositionAllocator(positionAlloc);

mobility.Install(c);

It represents the stationary or static nodes in a network simulation.

Also, install the model that we set, to all the nodes that we created.

internet.Install(c);

ipv4.SetBase("10.1.1.0", "255.255.255.0");

Ipv4InterfaceContainer i = ipv4.Assign(devices);

When the packet is received in the sinknode, we call RecievePacket function.

ReceivePacket(Ptr<Socket> socket)

{

while (socket->Recv()){ }

}

Here, we are invoking the receive functionality of the socket.

GenerateTraffic(Ptr<Socket> socket, uint32_t pktSize, uint32_t pktCount, Time pktInterval)

{

socket->Send(Create<Packet>(pktSize));

Simulator::Schedule(pktInterval,

&GenerateTraffic,

socket,

pktSize,

pktCount - 1,

pktInterval);

}

else

{

socket->Close();

}

We also schedule the simulator to invoke the GenerateTraffic function.

When the number of packets is zero, we close the socket.

Then, we stop invoking send function.

10),&GenerateTraffic,source,packetSize,numPackets,interval);

This procedure happens after ten seconds from the start of execution.

flowMonitor= flowHelper.InstallAll();

The created object returns a pointer to the flow classifier.

iter arrow first is used to collect the ID of the flow.

iter arrow second is used to collect the data associated with the flow.

We will analyze the type of flow and print the delay and throughput.

Navigate to the ns-allinone-3.38/ns3.38 directory

Type mv ~/Downloads/wifi-simple-infra.cc scratch/wifi-simple-infra.cc to move the source file to scratch directory.

Open the terminal by pressing Ctrl, Alt and T keys simultaneously.

Using the cd command, navigate to the installation directory of ns-3.

Go to the ns-3.38 directory.

Move your source file to the scratch directory within the ns-3.38 directory.

wifi-simple-infra.cc is the name of the source file.

TxPackets refers to the packets sent whereas RxPackets refers to the packets received.

We also see the average end to end delay and throughput of the wireless network.

Type cd ..

Type cd netanim

Navigate to the netanim directory under ns-allinone-3.38.

For that, type cd .. in the terminal window.

Then type cd netanim

The NetAnim window should open.

Then select the animationwifi-infra-2.xml file.

Close the NetAnim window

We see the flow details of the wireless network.

Now, we can close the NetAnim window.

In this tutorial, we have

• Created an infrastructure based wireless network.
• Created three UDP flows in the channels.
• Analyzed the flow using a flow monitor.
• Visualized the network using NetAnim.

• Create a simulation for a wireless network with three nodes.
• Create one access point (AP) and two stations.
• The AP and stations should use an 802.11g physical layer.
• Implement UDP traffic between the stations and the AP.
• Set packet size as 1500 bytes and send 200 packets from each station to the AP.
• Set the RSS at the AP to -70 dBm.
• Set the interval between packets to 0.005 seconds.
• Analyze the flow using flow monitor.
• Visualize the network using NetAnim.

Assignment- Observation

Assignment- Observation

Observe the packet transfer.

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