How to Implement multicast routing in ns3

To implement multicast routing in ns3, we have to create a multicast routing protocol, that configures multicast routes, and sets up multicast applications.

Let’s dive into the detailed explanation on implementing multicast routing in ns3 that uses a custom protocol.

Steps for implementation

1. Set up your ns3 :

• Make sure that ns3 is installed in the computer. If not, install it.

 

2. Include necessary libraries :

• In your script, include the necessary libraries.

 

3. Define network topology :

• For your network topology, create the nodes and links.

4. Install Internet Stack :

• On your nodes, install the internet stack.

5. Configure the multicast routing protocol :

• Create a custom routing protocol class to implement the behavior of multicast routing protocol.

6. Set Up Applications :

• To generate traffic and test the routing, install applications.

7. Run the Simulation :

• Define the simulation parameters and run it.

 

Example implementation in C++

 

Here is a complete example on implementing a basic multicast routing protocol in ns3:

Include libraries :

#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/ipv4-routing-protocol.h”

#include “ns3/ipv4-list-routing-helper.h”

#include “ns3/ipv4-static-routing-helper.h”

Define Network Topology:

using namespace ns3;

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

CommandLine cmd;

cmd.Parse(argc, argv);

NodeContainer nodes;

nodes.Create(4);

PointToPointHelper pointToPoint;

pointToPoint.SetDeviceAttribute(“DataRate”, StringValue(“5Mbps”));

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

NetDeviceContainer devices01, devices12, devices23, devices30;

devices01 = pointToPoint.Install(nodes.Get(0), nodes.Get(1));

devices12 = pointToPoint.Install(nodes.Get(1), nodes.Get(2));

devices23 = pointToPoint.Install(nodes.Get(2), nodes.Get(3));

devices30 = pointToPoint.Install(nodes.Get(3), nodes.Get(0));

InternetStackHelper stack;

stack.Install(nodes);

Ipv4AddressHelper address;

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

Ipv4InterfaceContainer interfaces01 = address.Assign(devices01);

address.SetBase(“10.1.2.0”, “255.255.255.0”);

Ipv4InterfaceContainer interfaces12 = address.Assign(devices12);

address.SetBase(“10.1.3.0”, “255.255.255.0”);

Ipv4InterfaceContainer interfaces23 = address.Assign(devices23);

address.SetBase(“10.1.4.0”, “255.255.255.0”);

Ipv4InterfaceContainer interfaces30 = address.Assign(devices30);

Configure Multicast Routes:

Ipv4StaticRoutingHelper multicastRoutingHelper;

// Node 0 as multicast source

Ptr<Ipv4> ipv4_0 = nodes.Get(0)->GetObject<Ipv4>();

Ptr<Ipv4StaticRouting> multicastRouting_0 = multicastRoutingHelper.GetStaticRouting(ipv4_0);

multicastRouting_0->AddMulticastRoute(Ipv4Address(“10.1.1.1”), Ipv4Address(“224.0.0.1”), Ipv4Address(“10.1.1.2”), 1);

// Node 1 as a multicast forwarder

Ptr<Ipv4> ipv4_1 = nodes.Get(1)->GetObject<Ipv4>();

Ptr<Ipv4StaticRouting> multicastRouting_1 = multicastRoutingHelper.GetStaticRouting(ipv4_1);

multicastRouting_1->AddMulticastRoute(Ipv4Address(“10.1.1.1”), Ipv4Address(“224.0.0.1”), Ipv4Address(“10.1.2.2”), 2);

multicastRouting_1->AddMulticastRoute(Ipv4Address(“10.1.1.1”), Ipv4Address(“224.0.0.1”), Ipv4Address(“10.1.1.1”), 1);

// Node 2 as a multicast forwarder

Ptr<Ipv4> ipv4_2 = nodes.Get(2)->GetObject<Ipv4>();

Ptr<Ipv4StaticRouting> multicastRouting_2 = multicastRoutingHelper.GetStaticRouting(ipv4_2);

multicastRouting_2->AddMulticastRoute(Ipv4Address(“10.1.1.1”), Ipv4Address(“224.0.0.1”), Ipv4Address(“10.1.3.2”), 2);

multicastRouting_2->AddMulticastRoute(Ipv4Address(“10.1.1.1”), Ipv4Address(“224.0.0.1”), Ipv4Address(“10.1.2.1”), 1);

// Node 3 as a multicast receiver

Ptr<Ipv4> ipv4_3 = nodes.Get(3)->GetObject<Ipv4>();

Ptr<Ipv4StaticRouting> multicastRouting_3 = multicastRoutingHelper.GetStaticRouting(ipv4_3);

multicastRouting_3->AddMulticastRoute(Ipv4Address(“10.1.1.1”), Ipv4Address(“224.0.0.1”), Ipv4Address(“10.1.3.1”), 1);

Set Up Multicast Applications:

uint16_t port = 9;

// Create a multicast source application on Node 0

OnOffHelper multicastSource(“ns3::UdpSocketFactory”, Address(InetSocketAddress(Ipv4Address(“224.0.0.1”), port)));

multicastSource.SetConstantRate(DataRate(“500kbps”));

ApplicationContainer sourceApps = multicastSource.Install(nodes.Get(0));

sourceApps.Start(Seconds(1.0));

sourceApps.Stop(Seconds(10.0));

// Create a multicast receiver application on Node 3

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

ApplicationContainer sinkApps = multicastSink.Install(nodes.Get(3));

sinkApps.Start(Seconds(1.0));

sinkApps.Stop(Seconds(10.0));

Simulator::Run();

Simulator::Destroy();

return 0;

}

Explanation

1. Network Topology :

The six nodes connected in a specific configuration, to set up the network topology.

2. multicast routing protocol Routing Protocol :

The Ipv4StaticRoutingHelper is used to configure multicast routes manually for each node.

3. Route configuration :

On the each node’s routing table add the static multicast routes. For example, Node 0 has a multicast route to the network 224.0.0.1 via the interface connected to Node 1.

4. Applications :

An OnOffHelper is used to generate multicast traffic from Node 0, and a PacketSinkHelper is used to receive multicast traffic on Node 3.

 

Running the Code :

Save your script to a file, for example, multicast-routing.cc and Compile the script using the ns3 build system

./waf configure –enable-examples

./waf build

./waf –run scratch/multicast-routing

Overall, we had successfully learned on implementing multicast routing in ns3 creating a multicast routing protocol, configuring multicast routes, and setting up multicast applications. We provide more related comparative analysis on multicast routing based on your project.