How to Start Hot Potato Routing Projects Using NS3

To start Hot Potato Routing using NS3 which is a form of deflection routing in which packets are sent to any available next-hop, still if it is suboptimal, to avoid buffering or delays. This method is generally utilized in networks including minimal or no queuing like optical networks.

We will guide you on how to make a Hot Potato Routing project in NS3:

Steps to Start Hot Potato Routing Projects in NS3

1. Understand Hot Potato Routing

• Key Features:
  • No Buffering: Packets are instantly sent to prevent the delay.
  • Best Effort Forwarding: The router selects any available next-hop.
  • Applications: This routing is used in high-speed and low-latency networks such as optical networks or scenarios where queueing is not necessary.
• Challenges:
  • It can cause to suboptimal routes.
  • Maximized packet loss if no valid next-hop is obtainable.

2. Set Up NS3

1. Install NS3:

sudo apt update

sudo apt install g++ python3 git cmake

git clone https://gitlab.com/nsnam/ns-3-dev.git

cd ns-3-dev

./waf configure

./waf build

1. Verify the setup:

./waf –run scratch/my-first

3. Implementing Hot Potato Routing

Hot Potato Routing doesn’t support built-in execution within NS3, thus we will require making a custom routing protocol.

4. Option 1: Custom Hot Potato Routing Protocol

Steps:

1. Create a New Protocol Class:
   • To prolong Ipv4RoutingProtocol.
   • Execute the forwarding logic to dynamically choice any available next-hop.
2. Key Functionalities:
   • RouteOutput: We describe how packets to depart the node are routed.
   • RouteInput: According to the Hot Potato strategy to manage incoming packets and send them.
3. Skeleton Code:

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

#include “ns3/log.h”

namespace ns3 {

class HotPotatoRouting : public Ipv4RoutingProtocol {

public:

static TypeId GetTypeId();

HotPotatoRouting();

virtual ~HotPotatoRouting();

Ptr<Ipv4Route> RouteOutput(Ptr<Packet> packet, const Ipv4Header &header,

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

bool RouteInput(Ptr<const Packet> packet, const Ipv4Header &header,

Ptr<const NetDevice> idev, UnicastForwardCallback ucb,

MulticastForwardCallback mcb, LocalDeliverCallback lcb,

ErrorCallback ecb) override;

private:

void ForwardPacket(const Ipv4Header &header, Ptr<Packet> packet, Ptr<NetDevice> outDevice);

};

} // namespace ns3

1. Implement Routing Logic:
   • Forwarding to the First Available Neighbor:
     • Probe the neighbor list of node and then transmit the packet to the initial available next-hop.
   • Drop if No Neighbor Exists:
     • If invalid next-hop occurs then drip the packet replicating a failure.

Example of Forwarding Logic:

void HotPotatoRouting::ForwardPacket(const Ipv4Header &header, Ptr<Packet> packet, Ptr<NetDevice> outDevice) {

for (auto neighbor : neighborTable) {

Ptr<NetDevice> device = neighbor.second; // Get a neighbor’s NetDevice

if (device->IsUp()) {

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

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

route->SetGateway(neighbor.first); // Gateway is the neighbor’s IP

route->SetOutputDevice(device);

// Send the packet

Ptr<Socket> socket = Socket::CreateSocket(GetObject<Node>(), UdpSocketFactory::GetTypeId());

socket->SendTo(packet, 0, InetSocketAddress(route->GetDestination(), 9));

return;

}

}

// If no neighbors are available, drop the packet

NS_LOG_WARN(“Dropping packet: No valid next-hop available.”);

}

5. Option 2: Modify Static Routing for Hot Potato Logic

Now, we can change the Ipv4StaticRoutingHelper of NS3 with deflection logic.

Steps:

1. Override Static Routing Behavior:
   • We need to select a random or first-available next-hop, rather than to utilize the shortest path.
2. Example Integration:

Ptr<Ipv4StaticRouting> staticRouting = staticRoutingHelper.GetStaticRouting(node->GetObject<Ipv4>());

staticRouting->AddHostRouteTo(Ipv4Address(“10.1.2.1”), Ipv4Address(“10.1.1.2”), 1);

// Override decision with Hot Potato logic

if (!routeAvailable) {

staticRouting->AddHostRouteTo(Ipv4Address(“10.1.3.1”), Ipv4Address(“10.1.1.3”), 2);

}

6. Simulate Hot Potato Routing

Topology Setup:

Monitor the deflection to make a basic network including several routes.

NodeContainer nodes;

nodes.Create(4);

PointToPointHelper pointToPoint;

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

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

NetDeviceContainer devices1 = pointToPoint.Install(nodes.Get(0), nodes.Get(1));

NetDeviceContainer devices2 = pointToPoint.Install(nodes.Get(1), nodes.Get(2));

NetDeviceContainer devices3 = pointToPoint.Install(nodes.Get(2), nodes.Get(3));

NetDeviceContainer devices4 = pointToPoint.Install(nodes.Get(0), nodes.Get(2));

7. Testing and Debugging

1. Enable Logging:

NS_LOG=”HotPotatoRouting” ./waf –run hot-potato-routing

1. Verify Routing Decisions:
   • Confirm routing tables and then we monitor how packets are turned aside.
   • For traffic analysis, we can utilize .pcap files:

pointToPoint.EnablePcapAll(“hot-potato-routing”);

In this module, we had observed how to create the Hot Potato Routing and how to implement it in two ways using NS3 simulation tool. More insights regarding to this project will be made available.

Our developers focus on achieving minimal or no queuing, similar to optical networks, ensuring that your project results are customized to your needs. Reach out to us for more information on Hot Potato Routing Projects. Using NS3, we offer you essential steps and provide thorough guidance for a better understanding.