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How to Implement shortest path routing in ns3

To implement shortest path routing in ns3, by creating a custom routing protocol to calculate the shortest paths between nodes in the network.

The following steps will guide to implement the basic shortest path routing protocol in ns3 with an example script.

Step-by-Step guide to Implement shortest path routing in ns3:

  1. Set Up ns-3 Environment: Make sure that ns3 is installed on the system.
  2. Include Necessary Libraries: The required ns3 libraries need to be included in the script.
  3. Define Network Topology: Create the nodes and links for the network topology.
  4. Implement the Shortest Path Routing Protocol: To compute the shortest path we need to create a custom routing protocol class.
  5. Integrate the Custom Routing Protocol: Integrate the custom routing protocol into the ns3 stack.
  6. Set Up Applications: Install applications to generate traffic and test the routing.
  7. Run the Simulation: Configure the simulation parameters and run it.

Implementation in C++

Here’s a detailed example to help you implement shortest path routing in ns-3:

  1. 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-list-routing-helper.h”

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

  1. 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 devices;

devices.Add(pointToPoint.Install(nodes.Get(0), nodes.Get(1)));

devices.Add(pointToPoint.Install(nodes.Get(1), nodes.Get(2)));

devices.Add(pointToPoint.Install(nodes.Get(2), nodes.Get(3)));

devices.Add(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”);

address.Assign(devices);

  1. Implement the Shortest Path Routing Protocol:
  • Create a new header file shortest-path-routing.h:

#ifndef SHORTEST_PATH_ROUTING_H

#define SHORTEST_PATH_ROUTING_H

#include “ns3/ipv4-routing-protocol.h”

#include “ns3/ipv4.h”

#include “ns3/ipv4-routing-table-entry.h”

#include “ns3/net-device.h”

#include “ns3/ptr.h”

#include “ns3/socket.h”

namespace ns3 {

class ShortestPathRouting : public Ipv4RoutingProtocol {

public:

static TypeId GetTypeId(void);

ShortestPathRouting();

virtual ~ShortestPathRouting();

virtual Ptr<Ipv4Route> RouteOutput(

Ptr<Packet> p, const Ipv4Header &header,

Ptr<NetDevice> oif, Socket::SocketErrno &sockerr);

virtual bool RouteInput(

Ptr<const Packet> p, const Ipv4Header &header,

Ptr<const NetDevice> idev,

UnicastForwardCallback ucb, MulticastForwardCallback mcb,

LocalDeliverCallback lcb, ErrorCallback ecb);

virtual void NotifyInterfaceUp(uint32_t interface);

virtual void NotifyInterfaceDown(uint32_t interface);

virtual void NotifyAddAddress(uint32_t interface, Ipv4InterfaceAddress address);

virtual void NotifyRemoveAddress(uint32_t interface, Ipv4InterfaceAddress address);

virtual void SetIpv4(Ptr<Ipv4> ipv4);

private:

void CalculateShortestPaths();

void AddHostRouteTo(uint32_t dest, Ptr<Ipv4Route> route);

std::vector<Ipv4RoutingTableEntry> m_routes;

Ptr<Ipv4> m_ipv4;

};

}

#endif // SHORTEST_PATH_ROUTING_H

Create the corresponding implementation file shortest-path-routing.cc:

#include “shortest-path-routing.h”

#include “ns3/log.h”

#include “ns3/ipv4-routing-table-entry.h”

namespace ns3 {

NS_LOG_COMPONENT_DEFINE(“ShortestPathRouting”);

NS_OBJECT_ENSURE_REGISTERED(ShortestPathRouting);

TypeId ShortestPathRouting::GetTypeId(void) {

static TypeId tid = TypeId(“ns3::ShortestPathRouting”)

.SetParent<Ipv4RoutingProtocol>()

.SetGroupName(“Internet”)

.AddConstructor<ShortestPathRouting>();

return tid;

}

ShortestPathRouting::ShortestPathRouting() {

NS_LOG_FUNCTION(this);

}

ShortestPathRouting::~ShortestPathRouting() {

NS_LOG_FUNCTION(this);

}

void ShortestPathRouting::SetIpv4(Ptr<Ipv4> ipv4) {

NS_LOG_FUNCTION(this << ipv4);

m_ipv4 = ipv4;

CalculateShortestPaths();

}

void ShortestPathRouting::CalculateShortestPaths() {

NS_LOG_FUNCTION(this);

// Implement Dijkstra’s or other shortest path algorithm here

}

Ptr<Ipv4Route> ShortestPathRouting::RouteOutput(

Ptr<Packet> p, const Ipv4Header &header, Ptr<NetDevice> oif,

Socket::SocketErrno &sockerr) {

NS_LOG_FUNCTION(this << p << header << oif << sockerr);

// Implement route output logic

return 0;

}

bool ShortestPathRouting::RouteInput(

Ptr<const Packet> p, const Ipv4Header &header,

Ptr<const NetDevice> idev, UnicastForwardCallback ucb,

MulticastForwardCallback mcb, LocalDeliverCallback lcb,

ErrorCallback ecb) {

NS_LOG_FUNCTION(this << p << header << idev << ucb << mcb  << lcb << ecb);

// Implement route input logic

return false;

}

void ShortestPathRouting::NotifyInterfaceUp(uint32_t interface) {

NS_LOG_FUNCTION(this << interface);

}

void ShortestPathRouting::NotifyInterfaceDown(uint32_t interface) {

NS_LOG_FUNCTION(this << interface);

}

voidShortestPathRouting::NotifyAddAddress(uint32_tinterface,Ipv4InterfaceAddress address) {

NS_LOG_FUNCTION(this << interface << address);

}

void ShortestPathRouting::NotifyRemoveAddress(uint32_t interface,

Ipv4InterfaceAddress address) {

NS_LOG_FUNCTION(this << interface << address);

}

void ShortestPathRouting::AddHostRouteTo(uint32_t dest,

Ptr<Ipv4Route> route) {

NS_LOG_FUNCTION(this << dest << route);

// Implement logic to add host route

}

}

  1. Integrate the Custom Routing Protocol:

#include “shortest-path-routing.h”

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 devices;

devices.Add(pointToPoint.Install(nodes.Get(0), nodes.Get(1)));

devices.Add(pointToPoint.Install(nodes.Get(1), nodes.Get(2)));

devices.Add(pointToPoint.Install(nodes.Get(2), nodes.Get(3)));

devices.Add(pointToPoint.Install(nodes.Get(3), nodes.Get(0)));

 

InternetStackHelper stack;

ShortestPathRoutingHelper shortestPathRouting;

Ipv4ListRoutingHelper list;

list.Add(shortestPathRouting, 0);

stack.SetRoutingHelper(list);

stack.Install(nodes);

Ipv4AddressHelper address;

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

address.Assign(devices);

// Set up applications

uint16_t port = 9;

UdpEchoServerHelper server(port);

ApplicationContainer apps = server.Install(nodes.Get(3));

apps.Start(Seconds(1.0));

apps.Stop(Seconds(10.0));

UdpEchoClientHelper client(address.GetAddress(3), port);

client.SetAttribute(“MaxPackets”, UintegerValue(1));

client.SetAttribute(“Interval”, TimeValue(Seconds(1.0)));

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

apps = client.Install(nodes.Get(0));

apps.Start(Seconds(2.0));

apps.Stop(Seconds(10.0));

Simulator::Run();

Simulator::Destroy();

return 0;

}

  1. Running the Code
  1. Save the script to a file, for example, shortest-path-routing.cc.
  2. Compile the script using the ns3 build system

./waf configure –enable-examples

./waf build

./waf –run scratch/shortest-path-routing

Overall, we had clearly explained about the implementation process of shortest path routing protocol in ns3 by using an appropriate algorithm. Implementation of shortest path routing in ns3 with best programming are done by us .