How to Begin Implement Adaptive Routing in NS3

To execute the Adaptive Routing using NS3, we can make a routing protocol which modifies their route selection dynamically according to the network conditions like congestion, delay, or link quality. Adaptive routing protocols focuses on enhance the network performance within real-time that is specifically effective in dynamic environments such as Mobile Ad-Hoc Networks (MANETs) or Wireless Sensor Networks (WSNs).

Below is a stepwise strategy to get started with Adaptive Routing in NS3:

Steps to Begin Implement Adaptive Routing in NS3

Step 1: Define Protocol Objectives

1. Dynamic Path Selection:
   • Depends on the performance parameters such as latency, congestion, bandwidth, or packet loss to modify routes for path selection.
2. Protocol Features:
   • Dynamically modernize routing tables according to the network changes.
   • Periodic monitoring of network metrics.
   • Sustain minimal control overhead.
3. Use Case:
   • Environments including the high mobility or fluctuating traffic like MANETs, IoT networks, or data centers.

Step 2: Set Up NS3 Environment

1. Create a New Protocol:
   • Make a new protocol directory in src/ as src/adaptive-routing/.
2. Add Required Files:
   • adaptive-routing-protocol.h: It describes the structure of protocol.
   • adaptive-routing-protocol.cc: Execute the protocol logic.
   • adaptive-routing-helper.h and adaptive-routing-helper.cc: For routing integration, we can make helper classes.
3. Update Build System:
   • Fine-tune the wscript in src/ with the protocol.

Step 3: Design Adaptive Routing Protocol

1. Define the Protocol Class

Create a protocol class by prolonging the Ipv4RoutingProtocol class for executing the adaptive routing logic.

Header File (adaptive-routing-protocol.h)

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

#include “ns3/socket.h”

#include “ns3/timer.h”

#include <map>

class AdaptiveRoutingProtocol : public ns3::Ipv4RoutingProtocol {

public:

static ns3::TypeId GetTypeId (void);

AdaptiveRoutingProtocol ();

virtual ~AdaptiveRoutingProtocol ();

// Ipv4RoutingProtocol methods

virtual ns3::Ptr<ns3::Ipv4Route> RouteOutput (

ns3::Ptr<const ns3::Packet> packet,

const ns3::Ipv4Header &header,

ns3::Ptr<ns3::NetDevice> oif,

ns3::Socket::SocketErrno &sockerr);

virtual bool RouteInput (

ns3::Ptr<const ns3::Packet> packet,

const ns3::Ipv4Header &header,

ns3::Ptr<const ns3::NetDevice> idev,

ns3::UnicastForwardCallback ucb,

ns3::MulticastForwardCallback mcb,

ns3::LocalDeliverCallback lcb,

ns3::ErrorCallback ecb);

// Adaptive Routing-specific methods

void MonitorNetworkConditions ();

void UpdateRoutingTable ();

void ProcessMetrics (const ns3::Ipv4Address &source, const ns3::Ipv4Address &dest, uint32_t delay, uint32_t bandwidth);

private:

ns3::Ptr<ns3::Socket> m_socket;

ns3::Ipv4Address m_selfAddress;

std::map<ns3::Ipv4Address, uint32_t> m_metricTable; // Destination -> Metric

std::map<ns3::Ipv4Address, ns3::Ipv4Address> m_routingTable; // Destination -> Next Hop

ns3::Timer m_monitorTimer; // Periodic monitoring timer

};

2. Implement Core Functions

Network Monitoring

Observe the network parameters periodically such as delay, bandwidth, or packet loss.

void AdaptiveRoutingProtocol::MonitorNetworkConditions () {

// Example: Send probes to neighbors and measure round-trip time

for (auto &neighbor : m_routingTable) {

ns3::Ptr<ns3::Packet> probe = ns3::Create<ns3::Packet> ();

m_socket->SendTo(probe, 0, ns3::InetSocketAddress(neighbor.first, 9999));

}

// Reschedule monitoring

m_monitorTimer.Schedule(ns3::Seconds(1.0));

}

Update Routing Table

Rely on monitored metrics, actively modernize the routes.

void AdaptiveRoutingProtocol::UpdateRoutingTable () {

for (auto &entry : m_metricTable) {

// Select next hop with the best metric

ns3::Ipv4Address bestNextHop = …; // Determine next hop based on metrics

m_routingTable[entry.first] = bestNextHop;

}

}

Process Metrics

It manages the incoming metric logs or analyse their replies.

void AdaptiveRoutingProtocol::ProcessMetrics (const ns3::Ipv4Address &source, const ns3::Ipv4Address &dest, uint32_t delay, uint32_t bandwidth) {

// Update metric table

m_metricTable[dest] = delay + (1000 / bandwidth); // Example: Composite metric

UpdateRoutingTable (); // Recompute routes

}

Packet Forwarding

Transmit the packets using RouteOutput and RouteInput.

ns3::Ptr<ns3::Ipv4Route> AdaptiveRoutingProtocol::RouteOutput (

ns3::Ptr<const ns3::Packet> packet,

const ns3::Ipv4Header &header,

ns3::Ptr<ns3::NetDevice> oif,

ns3::Socket::SocketErrno &sockerr) {

ns3::Ptr<ns3::Ipv4Route> route = ns3::Create<ns3::Ipv4Route> ();

if (m_routingTable.count(header.GetDestination ())) {

route->SetGateway(m_routingTable[header.GetDestination ()]);

} else {

sockerr = ns3::Socket::ERROR_NOROUTETOHOST;

return nullptr;

}

return route;

}

Step 4: Write a Helper Class

Make easier the protocol integration into simulation scripts using helper class.

#include “adaptive-routing-protocol.h”

class AdaptiveRoutingHelper {

public:

void Install (ns3::NodeContainer nodes) {

for (auto it = nodes.Begin(); it != nodes.End(); ++it) {

ns3::Ptr<AdaptiveRoutingProtocol> protocol = ns3::CreateObject<AdaptiveRoutingProtocol>();

(*it)->AggregateObject(protocol);

}

}

};

Step 5: Write a Simulation Script

Example Simulation Script

#include “ns3/core-module.h”

#include “ns3/network-module.h”

#include “ns3/internet-module.h”

#include “adaptive-routing-helper.h”

using namespace ns3;

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

NodeContainer nodes;

nodes.Create (5);

InternetStackHelper stack;

stack.Install (nodes);

AdaptiveRoutingHelper adaptiveHelper;

adaptiveHelper.Install (nodes);

PointToPointHelper p2p;

p2p.SetDeviceAttribute (“DataRate”, StringValue (“10Mbps”));

p2p.SetChannelAttribute (“Delay”, StringValue (“2ms”));

p2p.Install (nodes.Get(0), nodes.Get(1));

p2p.Install (nodes.Get(1), nodes.Get(2));

// Additional links as needed

Ipv4AddressHelper address;

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

address.Assign (p2p.Install (nodes.Get (0), nodes.Get (1)));

Simulator::Run ();

Simulator::Destroy ();

return 0;

}

Step 6: Compile and Run

1. Build the Protocol:

./waf configure

./waf build

1. Run the Simulation:

./waf –run your-script

Step 7: Analyze and Extend

1. Analyze Performance:
   • Examine the performance parameters such as throughput, latency, and packet loss to leverage FlowMonitor or PcapHelper.
2. Enhance Adaptive Behavior:
   • Integrate direct support for mobility or dynamic bandwidth modifications.
   • Execute fallback approaches for route failures.

In this procedure, you can grasp more essential facts through this manual regarding on how to execute and analyze the Adaptive Routing using NS3 tool by defining protocol class, make simulation script and extend and analyse their performance. You can also extend the implementation or customize it further.