To implement adaptive routing in ns3, we need to make a custom routing protocol that dynamically regulates routes based on varying network condition like traffic load, link quality, or varying topology. Get best implementation of adaptive routing in ns3 from ns3simulation.com. The given below is the procedure to achieve this:

Step-by-Step Implementation

1. Set Up ns3 Environment: Make certain ns3 is installed in the system. If not, download and install it from the ns3 official website.
2. Include Necessary Libraries: to contains the essential ns3 libraries in the script
3. Define Network Topology: To make the nodes and links for your network topology.
4. Implement the Adaptive Routing Protocol: to make personalize routing protocol that observes network conditions and update the routes.
5. Integrate the Custom Routing Protocol: Incorporated the custom routing protocol in ns3 stack.
6. Set up Applications: Install applications to create the traffic and test the routing.
7. Run the Simulation: Configure the simulation parameters and run it.

Example Implementation in C++

The given below is the sample script to implement an adaptive routing protocol in ns3 tool:

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”

2. 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);

3. Implement the Adaptive Routing Protocol:

• Create a new header file adaptive-routing.h:

#ifndef ADAPTIVE_ROUTING_H

#define ADAPTIVE_ROUTING_H

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

#include “ns3/ipv4.h”

#include “ns3/net-device.h”

#include “ns3/ptr.h”

#include “ns3/socket.h”

namespace ns3 {

    class AdaptiveRouting : public Ipv4RoutingProtocol {

    public:

        static TypeId GetTypeId(void);

        AdaptiveRouting();

        virtual ~AdaptiveRouting();

        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 MonitorNetworkConditions();

        void UpdateRoutingTable();

        Ptr<Ipv4> m_ipv4;

        std::map<Ipv4Address, Ptr<Socket>> m_socketMap;

        // Other data structures for adaptive routing state

    };

}

#endif // ADAPTIVE_ROUTING_H

Create the corresponding implementation file adaptive-routing.cc:

#include “adaptive-routing.h”

#include “ns3/log.h”

#include “ns3/simulator.h”

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

#include <algorithm>

namespace ns3 {

    NS_LOG_COMPONENT_DEFINE(“AdaptiveRouting”);

    NS_OBJECT_ENSURE_REGISTERED(AdaptiveRouting);

    TypeId AdaptiveRouting::GetTypeId(void) {

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

            .SetParent<Ipv4RoutingProtocol>()

            .SetGroupName(“Internet”)

            .AddConstructor<AdaptiveRouting>();

        return tid;

    }

    AdaptiveRouting::AdaptiveRouting() {

        NS_LOG_FUNCTION(this);

        Simulator::Schedule(Seconds(1.0), &AdaptiveRouting::MonitorNetworkConditions, this);

    }

    AdaptiveRouting::~AdaptiveRouting() {

        NS_LOG_FUNCTION(this);

    }

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

        NS_LOG_FUNCTION(this << ipv4);

        m_ipv4 = ipv4;

        UpdateRoutingTable();

    }

    void AdaptiveRouting::MonitorNetworkConditions() {

        NS_LOG_FUNCTION(this);

        // Implement network monitoring logic

        // This can include checking link utilization, delay, packet loss, etc.

        UpdateRoutingTable();

        Simulator::Schedule(Seconds(1.0),&AdaptiveRouting::MonitorNetworkConditions, this);

    }

    void AdaptiveRouting::UpdateRoutingTable() {

        NS_LOG_FUNCTION(this);

        // Implement routing table update logic based on network conditions

        // Example: Using link state information to update routes

        // Clear existing routes

        m_ipv4->GetRoutingProtocol()->Clear();

        // Get the list of all nodes in the network

        NodeContainer allNodes = NodeContainer::GetGlobal();

        // Calculate the shortest path to each node

        for (NodeContainer::Iterator it = allNodes.Begin(); it != allNodes.End(); ++it) {

            Ptr<Node> node = *it;

            // Skip the current node

            if (node == m_ipv4->GetObject<Node>()) continue;

            // Calculate the shortest path to this node

            Ptr<Ipv4Route> route = Create<Ipv4Route>();

            route->SetDestination(node->GetObject<Ipv4>()->GetAddress(1, 0).GetLocal());

            route->SetGateway(Ipv4Address(“0.0.0.0”)); // Assuming direct connection for simplicity route->SetOutputDevice(m_ipv4->GetNetDevice(1));

            // Add the route

            m_ipv4->GetRoutingProtocol()->AddNetworkRouteTo(route->GetDestination(), Ipv4Mask(“255.255.255.255”), route->GetGateway(), route->GetOutputDevice());

        }

    }

    Ptr<Ipv4Route> AdaptiveRouting::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

        // For simplicity, use a static route

        Ptr<Ipv4Route> route = Create<Ipv4Route>();

        route->SetDestination(header.GetDestination());

        route->SetGateway(Ipv4Address(“10.1.1.2”));

        route->SetOutputDevice(m_ipv4->GetNetDevice(1));

        return route;

    }

    bool AdaptiveRouting::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

        // Check if the packet is destined for this node

        if (header.GetDestination() == m_ipv4->GetAddress(1, 0).GetLocal()) {

            lcb(p, header, idev);

            return true;

        }

        // Otherwise, forward the packet using the adaptive routing table

        Ptr<Ipv4Route> route = Create<Ipv4Route>();

        route->SetDestination(header.GetDestination());

        route->SetGateway(Ipv4Address(“10.1.1.2”)); // Example gateway

        route->SetOutputDevice(m_ipv4->GetNetDevice(1));

        ucb(route, p, header);

        return true;

    }

    void AdaptiveRouting::NotifyInterfaceUp(uint32_t interface) {

        NS_LOG_FUNCTION(this << interface);

    }

    void AdaptiveRouting::NotifyInterfaceDown(uint32_t interface) {

        NS_LOG_FUNCTION(this << interface);

    }

    void AdaptiveRouting::NotifyAddAddress(uint32_t interface, Ipv4InterfaceAddress address) {

        NS_LOG_FUNCTION(this << interface << address);

    }

    void AdaptiveRouting::NotifyRemoveAddress(uint32_t interface,Ipv4InterfaceAddress address) {

        NS_LOG_FUNCTION(this << interface << address);

    }

}

4. Integrate the Custom Routing Protocol:

#include “adaptive-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;

    AdaptiveRoutingHelper adaptiveRouting;

    Ipv4ListRoutingHelper list;

    list.Add(adaptiveRouting, 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;

}

Explanation

The given below is the explanation for the adaptive routing process:

1. Network Topology: The code sets up a simple network topology with four nodes connected in a ring.
2. Adaptive Routing Protocol: A custom adaptive routing protocol class (AdaptiveRouting) is implemented. This class monitors network conditions and updates the routing table accordingly.
3. Monitor Network Conditions: The MonitorNetworkConditions method is called periodically to check network conditions and update the routing table.
4. Update Routing Table: The UpdateRoutingTable method recalculates the routes based on the current network conditions.
5. Integrate Custom Routing Protocol: The custom routing protocol is integrated into the ns-3 stack using the AdaptiveRoutingHelper.
6. Applications: UdpEchoServer and UdpEchoClient applications are set up to test the routing.

Running the Code

1. Save your script to a file, for example, adaptive-routing.cc.
2. Compile the script using the ns-3 build system

./waf configure –enable-examples

./waf build

./waf –run scratch/adaptive-routing

Overall, we had implemented adaptive routing in ns3 that creates network topology by using the adaptive routing procedures. We also support programming  related to  information for adaptive routing.