How to Begin Implement Network DHCP Management in NS3

To implement Dynamic Host Configuration Protocol (DHCP) Management in ns-3, we can replicate on how the IP addresses are dynamically allocated to network devices. Since ns-3 environment don’t have a built-in DHCP module, we require stimulating a DHCP behavior through generating a custom application or logic that implement the DHCP procedure.

Here’s how to implement DHCP management in ns-3 step by step:

Steps to Begin Implement Network DHCP Management in NS3

1. Understand DHCP Management

• DHCP Overview:
  • Dynamically allocate the IP addresses and other network parameters to devices.
  • Uses a pool for possible the IPs to assign the addresses.
  • Function are using the request-response model:
    1. Discover: Client are propagate the request for an IP.
    2. Offer: It offers an IP address for DHCP server.
    3. Request: Client requests for delivered the IP address.
    4. Ack: DHCP server allocates the acknowledgement.

2. Set Up ns-3

• Install ns-3:

./waf configure –build-profile=debug –enable-examples –enable-tests

./waf build

• Validate the installation:

./waf –run hello-simulator

3. Define Network Topology

• Generate the nodes for clients, the DHCP server, and any routers or switches in the network.

Example: Basic Topology

#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”

using namespace ns3;

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

{

Time::SetResolution(Time::NS);

// Create nodes

NodeContainer nodes;

nodes.Create(3); // Node 0: Client, Node 1: Router/DHCP Server, Node 2: Server

// Configure point-to-point links

PointToPointHelper p2p;

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

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

// Install devices

NetDeviceContainer devices1 = p2p.Install(nodes.Get(0), nodes.Get(1)); // Client to Router/DHCP Server

NetDeviceContainer devices2 = p2p.Install(nodes.Get(1), nodes.Get(2)); // Router/DHCP Server to Server

// Install Internet stack

InternetStackHelper stack;

stack.Install(nodes);

// Assign static IP to the server

Ipv4AddressHelper address;

address.SetBase(“192.168.2.0”, “255.255.255.0”);

Ipv4InterfaceContainer serverInterface = address.Assign(devices2);

Simulator::Run();

Simulator::Destroy();

return 0;

}

4. Simulate DHCP Management
5. Implement a DHCP Server

• Handle the pool of IP addresses.
• For IP allocation response their client requests.

class DhcpServer

{

public:

DhcpServer(Ipv4Address start, Ipv4Address end)

{

m_nextAddress = start;

m_endAddress = end;

}

Ipv4Address Allocate()

{

if (m_nextAddress <= m_endAddress)

{

Ipv4Address allocated = m_nextAddress;

m_nextAddress.Set(m_nextAddress.Get() + 1);

return allocated;

}

else

{

NS_LOG_UNCOND(“DHCP Pool Exhausted”);

return Ipv4Address(“0.0.0.0”);

}

}

private:

Ipv4Address m_nextAddress;

Ipv4Address m_endAddress;

};

1. Implement a DHCP Client

• It replicate the Discover, Request, and Ack stages of DHCP.

class DhcpClient

{

public:

void RequestIp(DhcpServer &server)

{

Ipv4Address allocatedIp = server.Allocate();

if (allocatedIp != Ipv4Address(“0.0.0.0”))

{

NS_LOG_UNCOND(“DHCP Client: Received IP ” << allocatedIp);

}

else

{

NS_LOG_UNCOND(“DHCP Client: No IP available”);

}

}

};

1. Integrate DHCP Server and Clients

• Instantiate a DHCP server have a client of request in IP addresses.

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

{

Time::SetResolution(Time::NS);

NodeContainer nodes;

nodes.Create(3);

InternetStackHelper stack;

stack.Install(nodes);

// Initialize DHCP server

DhcpServer dhcp(Ipv4Address(“192.168.1.100”), Ipv4Address(“192.168.1.200”));

// Simulate DHCP requests

DhcpClient client;

Simulator::Schedule(Seconds(1.0), &DhcpClient::RequestIp, &client, std::ref(dhcp));

Simulator::Schedule(Seconds(2.0), &DhcpClient::RequestIp, &client, std::ref(dhcp));

Simulator::Run();

Simulator::Destroy();

return 0;

}

5. Add Logging for Debugging

• Use ns-3 logging for monitor the IP allocation and requests.

NS_LOG_COMPONENT_DEFINE(“DhcpManagement”);

void EnableLogging()

{

LogComponentEnable(“DhcpManagement”, LOG_LEVEL_INFO);

}

Call EnableLogging() in main() to activate detailed logs.

6. Simulate Multiple Clients

• Enhance the several clients for demand the IPs from DHCP server.
• Alter the DHCP pool size for validates the exhaustion environment.

7. Enhance DHCP Management

• Lease Mechanisms:
  • Enhance the lease expiration and renewal.
• Conflict Detection:
  • Identify the fake IPs.
• Options:
  • It includes the gateway, DNS server, and subnet cover the information in DHCP responses.

Example: Lease Renewal

void RenewLease(DhcpServer &server, Ipv4Address ip)

{

NS_LOG_UNCOND(“Renewing lease for IP: ” << ip);

// Logic to renew lease

}

8. Run and Test

• Generate and implement the replication of process:

./waf –run scratch/dhcp-management

• Test the logs for specifics the IP allocation.

9. Analyze Results

• Use logs for validate:
  • Correctness for IP allocation.
  • Manage the several clients.
  • DHCP pools are exhaustion situations.

10. Advanced Features

• Implement more sophisticated DHCP features:
  • Dynamic allocations are according to their subnets.
  • It replicates the real-world condition such as failover DHCP servers.
• Envision for network setting for using the tools such as gnuplot.

Here, we had implemented and executed the Dynamic Host Configuration Protocol in ns3 simulation tool. We will discover on how the DHCP evaluated within other simulation frameworks.