To implement a line topology in ns3, we need to follow several steps. This type of topologies are more useful in simulating scenarios such as bus or linear networks, for that we need create a network in which each node is connected to exactly two other nodes (except for the two end nodes, which are each connected to only one other node). Here the steps given below will guide on implementing Line topology in ns3.
Steps to Implement a Line Topology in NS3
- Set Up the NS3 Environment:
- Make sure NS3 is installed and properly configured.
- Create the Nodes:
- Create a set of nodes to represent the devices in the line network.
- Set Up the Point-to-Point Channels:
- Use point-to-point helpers to connect each node to its immediate neighbor, forming a line.
- Install Network Stack:
- Install the internet stack on all nodes.
- Assign IP Addresses:
- Assign IP addresses to the nodes connected by the point-to-point links.
- Set Up Applications:
- Install applications to generate traffic and demonstrate communication between nodes.
Example Code
Here is an example given to set up a simple line topology in NS3:
#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;
NS_LOG_COMPONENT_DEFINE (“LineTopologyExample”);
int main (int argc, char *argv[])
{
CommandLine cmd;
cmd.Parse (argc, argv);
// Create nodes
NodeContainer nodes;
nodes.Create (5); // Create 5 nodes for the line topology
// Create point-to-point links
PointToPointHelper pointToPoint;
pointToPoint.SetDeviceAttribute (“DataRate”, StringValue (“5Mbps”));
pointToPoint.SetChannelAttribute (“Delay”, StringValue (“2ms”));
InternetStackHelper stack;
stack.Install (nodes);
Ipv4AddressHelper address;
int subnet = 1;
// Connect each node to its neighbor to form a line
for (uint32_t i = 0; i < nodes.GetN () – 1; ++i)
{
NetDeviceContainer link = pointToPoint.Install (NodeContainer (nodes.Get (i), nodes.Get (i + 1)));
std::ostringstream subnetStream;
subnetStream << “10.1.” << subnet++ << “.0”;
address.SetBase (subnetStream.str ().c_str (), “255.255.255.0”);
address.Assign (link);
}
// Enable routing
Ipv4GlobalRoutingHelper::PopulateRoutingTables ();
// Create a UDP server on the last node
UdpServerHelper udpServer (9);
ApplicationContainer serverApp = udpServer.Install (nodes.Get (nodes.GetN () – 1));
serverApp.Start (Seconds (1.0));
serverApp.Stop (Seconds (10.0));
// Create a UDP client on the first node
UdpClientHelper udpClient (Ipv4Address (“10.1.4.2”), 9); // IP of the last node
udpClient.SetAttribute (“MaxPackets”, UintegerValue (320));
udpClient.SetAttribute (“Interval”, TimeValue (MilliSeconds (50)));
udpClient.SetAttribute (“PacketSize”, UintegerValue (1024));
ApplicationContainer clientApp = udpClient.Install (nodes.Get (0));
clientApp.Start (Seconds (2.0));
clientApp.Stop (Seconds (10.0));
// Enable packet capture
pointToPoint.EnablePcapAll (“line-topology”);
// Enable logging
LogComponentEnable (“UdpClient”, LOG_LEVEL_INFO);
LogComponentEnable (“UdpServer”, LOG_LEVEL_INFO);
Simulator::Run ();
Simulator::Destroy ();
return 0;
}
Explanation
- Setup: The code sets up a line topology with five nodes connected by point-to-point links.
- Point-to-Point Links: Point-to-point links are created to connect each node to its immediate neighbor, forming a line. The data rate and delay are configured for the links.
- Network Stack: The internet stack is installed on all nodes.
- IP Addresses: IP addresses are assigned to the nodes connected by the point-to-point links.
- Applications: A UDP server is installed on the last node in the line, and a UDP client is installed on the first node to generate traffic and demonstrate communication.
- Packet Capture: Packet capture is enabled for the point-to-point links to observe network traffic.
- Logging: Logging is enabled for the UDP client and server applications to provide detailed output during the simulation.
Running the Simulation
Compile and run the simulation using the following commands in NS3 environment:
./waf configure
./waf build
./waf –run line-topology-example
Replace line-topology-example with the actual name of the script file.
Over all we had learnt the process of implementing Line topology in ns3 from the above given example and steps. And this type of topologies are mainly used in bus or linear networks.
Implementation of Line Topology in ns3tool will be carried out by our programmers, so share with us all your project details and get best outcome.