How to Implement SDN in NS3

To implement software-Defined Networking (SDN) in ns-3 by creating a network topology where control plane is separated from the data plane, allowing a central controller to manage the network. The following steps will guide to implement the SDN-based network in ns-3 using open flow for the control plane.

Prerequisites

• ns-3 installed on your system.
• Basic understanding of ns-3, C++ programming, and SDN concepts.

Step-by-step to Implement SDN in ns-3

1. Install ns-3: Ensure you have ns-3 installed. You can download it from the official website and follow the installation instructions.

wget https://www.nsnam.org/release/ns-allinone-3.xx.tar.bz2

tar -xjf ns-allinone-3.xx.tar.bz2

cd ns-allinone-3.xx

./build.py –enable-examples –enable-tests

Include Necessary Headers: Include the required headers for OpenFlow and network modules.

#include “ns3/core-module.h”

#include “ns3/network-module.h”

#include “ns3/mobility-module.h”

#include “ns3/internet-module.h”

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

#include “ns3/applications-module.h”

#include “ns3/openflow-module.h”

Create Network Topology: Create nodes for hosts, switches, and the controller.

NodeContainer hosts;

hosts.Create(2);

NodeContainer switches;

switches.Create(1);

NodeContainer controllerNode;

controllerNode.Create(1);

Set Up Point-to-Point Links: Configure point-to-point links between the nodes.

PointToPointHelper pointToPoint;

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

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

NetDeviceContainer hostDevices;

NetDeviceContainer switchDevices;

for (uint32_t i = 0; i < hosts.GetN(); ++i) {

    NetDeviceContainer link = pointToPoint.Install(NodeContainer(hosts.Get(i), switches.Get(0)));

    hostDevices.Add(link.Get(0));

    switchDevices.Add(link.Get(1));

}

Install Internet Stack: Install the internet stack on the host nodes.

InternetStackHelper internet;

internet.Install(hosts);

Assign IP Addresses: Assign IP addresses to the host devices.

Ipv4AddressHelper address;

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

Ipv4InterfaceContainer hostInterfaces = address.Assign(hostDevices);

Set Up OpenFlow Switch: Configure the OpenFlow switch and connect it to the controller.

OpenFlowSwitchHelper ofSwitchHelper;

Ptr<ns3::ofi::Controller> controller = CreateObject<ns3::ofi::Controller>();

ofSwitchHelper.Install(switches.Get(0), switchDevices, controllerNode.Get(0));

Create Applications: Create and install applications on the host nodes to simulate traffic.

uint16_t port = 9;

OnOffHelperonoff(“ns3::UdpSocketFactory”, Address(InetSocketAddress(hostInterfaces.GetAddress(1), port)));

onoff.SetConstantRate(DataRate(“500kb/s”));

ApplicationContainer app = onoff.Install(hosts.Get(0));

app.Start(Seconds(1.0));

app.Stop(Seconds(10.0));

PacketSinkHelpersink(“ns3::UdpSocketFactory”, Address(InetSocketAddress(Ipv4Address::GetAny(), port)));

app = sink.Install(hosts.Get(1));

app.Start(Seconds(0.0));

app.Stop(Seconds(10.0));

Run the Simulation: Finally, run the simulation and clean up.

Simulator::Stop(Seconds(10.0));

Simulator::Run();

Simulator::Destroy();

Example Complete Script

Below is an example complete script for setting up a basic SDN network in ns-3:

#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”

#include “ns3/openflow-module.h”

using namespace ns3;

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

{

    NodeContainer hosts;

    hosts.Create(2);

    NodeContainer switches;

    switches.Create(1);

    NodeContainer controllerNode;

    controllerNode.Create(1);

    PointToPointHelper pointToPoint;

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

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

    NetDeviceContainer hostDevices;

    NetDeviceContainer switchDevices;

    for (uint32_t i = 0; i < hosts.GetN(); ++i) {

        NetDeviceContainer link = pointToPoint.Install(NodeContainer(hosts.Get(i), switches.Get(0)));

        hostDevices.Add(link.Get(0));

        switchDevices.Add(link.Get(1));

    }

    InternetStackHelper internet;

    internet.Install(hosts);

    Ipv4AddressHelper address;

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

    Ipv4InterfaceContainer hostInterfaces = address.Assign(hostDevices);

    OpenFlowSwitchHelper ofSwitchHelper;

    Ptr<ns3::ofi::Controller> controller = CreateObject<ns3::ofi::Controller>();

    ofSwitchHelper.Install(switches.Get(0), switchDevices, controllerNode.Get(0));

    uint16_t port = 9;

    OnOffHelper onoff(“ns3::UdpSocketFactory”, Address(InetSocketAddress(hostInterfaces.GetAddress(1), port)));

    onoff.SetConstantRate(DataRate(“500kb/s”));

    ApplicationContainer app = onoff.Install(hosts.Get(0));

    app.Start(Seconds(1.0));

    app.Stop(Seconds(10.0));

    PacketSinkHelper sink(“ns3::UdpSocketFactory”, Address(InetSocketAddress(Ipv4Address::GetAny(), port)));

    app = sink.Install(hosts.Get(1));

    app.Start(Seconds(0.0));

    app.Stop(Seconds(10.0));

    Simulator::Stop(Seconds(10.0));

    Simulator::Run();

    Simulator::Destroy();

    return 0;

}

Running the Script

Compile and run the script using the following commands:

./waf configure –enable-examples

./waf build

./waf –run <script-name>

Finally, Software-defined Networking (SDN) in ns-3 using OpenFlow for the control plane. All types of SDN-based network in ns-3 programs are handled by us.