How to Implement IPv4 Protocol in NS2

 

To implement the IPv4 protocols in ns2, start by understanding how IPv4 (Internet Protocol version 4) perform and then setting up or expanding to replicate the IPv4-relevant network scenarios. To execute the custom IPv4 mechanisms, we have to configure the simulation that utilizes the abilities or altering the ns2 because the simulation tool already supports the IPv4 over its available IP and routing modules.

The below is the step-by-step procedure to implement the IPv4 Protocol using ns2:

Step-by-Step Implementation:

Step 1: Understanding IPv4 in NS2

NS2 offers simplified IP routing through its Agent/RTAgent and based classes. These manage simple IPv4 packet forwarding, route management, and support for various IP-based protocols like TCP, UDP and so on. You can expand these classes or consume them as is to execute your particular demands.

Step 2: Set Up NS2

Make certain that the ns2 is installed and configure. Validate it by executing a basic simulation.

Step 3: Implement IPv4 Protocol Features

If you need to implement certain IPv4 functionalities (like custom routing, managing fragmentation, etc.), you will need to adjust or extend existing NS2 classes.

  1. Modifying IP Header Structure

You can start by extending the IP header structure if required:

#include <packet.h>

struct hdr_ipv4 {

int src_addr;

int dest_addr;

int ttl;

int protocol;

// Other fields as needed

static int offset_;

inline static hdr_ipv4* access(const Packet* p) {

return (hdr_ipv4*) p->access(offset_);

}

};

int hdr_ipv4::offset_;

  1. Implementing Custom IPv4 Agent

If you need a custom IP agent, you can generate a new agent class that manages IPv4 packets in a particular way:

#include <agent.h>

#include <packet.h>

#include <trace.h>

#include <address.h>

class CustomIPv4Agent : public Agent {

public:

CustomIPv4Agent();

void recv(Packet* p, Handler* h);

void forwardPacket(Packet* p);

protected:

std::map<int, int> routingTable_; // Destination -> Next Hop

};

// Constructor

CustomIPv4Agent::CustomIPv4Agent() : Agent(PT_TCP) {

// Initialize routing table or other necessary structures

}

// Packet reception

void CustomIPv4Agent::recv(Packet* p, Handler* h) {

hdr_ip* iph = hdr_ip::access(p);

if (iph->ttl() <= 0) {

// Drop packet if TTL is zero

drop(p);

return;

}

// Decrement TTL

iph->ttl()–;

// Forward the packet

forwardPacket(p);

}

// Forward packet to the next hop

void CustomIPv4Agent::forwardPacket(Packet* p) {

hdr_ip* iph = hdr_ip::access(p);

int dest = iph->daddr();

// Determine the next hop

if (routingTable_.find(dest) != routingTable_.end()) {

int nextHop = routingTable_[dest];

send(p, nextHop);

} else {

// Drop packet if no route is found

drop(p);

}

}

  1. Integrate Custom Protocol into NS2
  1. Modify the Makefile: Include your new CustomIPv4Agent class to the NS2 Makefile.
  2. Recompile NS2:

make clean

make

Step 4: Create a Tcl Script to Simulate the IPv4 Protocol

Set up a Tcl script to simulate a network using this protocol, after the compilation is done.

Example Tcl Script:

# Create a simulator object

set ns [new Simulator]

# Define the topology

set val(chan)   Channel/WiredChannel

set val(ll)     LL

set val(ifq)    Queue/DropTail/PriQueue

set val(ifqlen) 50

set val(stop)   50.0

# Initialize the topology object

set topo [new Topography]

$topo load_flatgrid 500 500

# Create nodes

set node1 [$ns node]

set node2 [$ns node]

set node3 [$ns node]

# Establish links between nodes

$ns duplex-link $node1 $node2 10Mb 10ms DropTail

$ns duplex-link $node2 $node3 10Mb 10ms DropTail

# Attach Custom IPv4 agent to nodes

set ip1 [new Agent/CustomIPv4Agent]

set ip2 [new Agent/CustomIPv4Agent]

set ip3 [new Agent/CustomIPv4Agent]

$ns attach-agent $node1 $ip1

$ns attach-agent $node2 $ip2

$ns attach-agent $node3 $ip3

# Set up traffic sources and sinks

set udp [new Agent/UDP]

set null [new Agent/Null]

$ns attach-agent $node1 $udp

$ns attach-agent $node3 $null

$ns connect $udp $null

# Start the simulation

$ns at 0.0 “$udp start”

$ns at $val(stop) “stop”

$ns at $val(stop) “exit 0”

proc stop {} {

global ns

$ns flush-trace

exit 0

}

# Run the simulation

$ns run

Step 5: Run the Simulation

  1. Save the Tcl script (ipv4_simulation.tcl).
  2. Open a terminal and navigate to the directory where you saved the Tcl script.
  3. Use the given command to execute the simulation:

ns ipv4_simulation.tcl

Step 6: Analyze the Results

  • Use trace files and the network animator (NAM) to evaluate the performance of the IPv4 protocol, aiming on metrics like packet delivery ratio, latency, and routing proficiency.
  • Assess how well your protocol manages numerous network scenarios as well as routing, packet forwarding, and TTL handling.

Additional Considerations

  • Advanced Features: Consider attaching modern IPv4 features like fragmentation, reassembly, or ICMP for error reporting.
  • Integration with Existing Protocols: Incorporate your custom IPv4 protocol with other protocols includes TCP/UDP, for end-to-end communication.
  • Scalability: Compute the scalability and performance by inspecting the protocol in larger networks with more nodes.

According to this procedure, we have seen and aggregated the essential information regarding the example including the setup of simplified IPV4 Protocols and their simulation process in the ns2 environment. We will also offer any additional details on this topic, if you need.

We offer comprehensive project network analysis services, ensuring your project is completed efficiently with our expertise. For assistance in implementing the IPv4 Protocol in NS2, you may visit ns2project.com, where we present a variety of excellent project topics. Our team is equipped to handle all types of simulation for your projects, so please stay connected with us for optimal outcomes.