How to Calculate Network DHCP Management in NS2

To calculate the Network Dynamic Host Configuration Protocol (DHCP) Management in NS2, we have to dynamically distribute the IP addresses to devices on a network by replicating the activities of DHCP. It makes certain that IP addresses are assigned efficiently ignores conflicts and automatically handles IP leases.

Since the NS2 lacks in-built features for DHCP, we have to simulate the DHCP-based actions by setting up a DHCP server node that allocates IP addresses to client nodes dynamically. The server can distribute IP leases, manage IP address request and handle renewals. We offered the computational process of DHCP in the following below:

Steps to Simulate and Calculate DHCP Management in NS2

  1. Set Up NS2 Simulation with DHCP-Like Behavior

Simulate the DHCP by designating a node as a DHCP server that dynamically allots IP addresses to client nodes upon request. Clients can then use the allocated IP addresses to interact inside the network.

Example NS2 Script for Simulating DHCP Management

# Create NS2 simulator instance

set ns [new Simulator]

# Open trace file for logging DHCP events

set tracefile [open dhcp_management_trace.tr w]

$ns trace-all $tracefile

# Define network nodes

set dhcp_server [$ns node]  ;# Node simulating DHCP server

set client1 [$ns node]      ;# Client node 1 requesting IP address from DHCP

set client2 [$ns node]      ;# Client node 2 requesting IP address from DHCP

# Create duplex links between nodes

$ns duplex-link $dhcp_server $client1 1Mb 10ms DropTail

$ns duplex-link $dhcp_server $client2 1Mb 10ms DropTail

# Simulate IP address pool (for simplicity, we’ll simulate this behavior manually)

# DHCP Server -> Assigns IP 192.168.1.1 to client1

# DHCP Server -> Assigns IP 192.168.1.2 to client2

# Set up UDP agents to simulate DHCP request and response messages

set udp_server [new Agent/UDP]

$ns attach-agent $dhcp_server $udp_server

set udp_client1 [new Agent/UDP]

$ns attach-agent $client1 $udp_client1

$ns connect $udp_client1 $udp_server

set udp_client2 [new Agent/UDP]

$ns attach-agent $client2 $udp_client2

$ns connect $udp_client2 $udp_server

# Set up CBR traffic to simulate DHCP request from clients (DHCPDISCOVER -> DHCPACK)

set discover1 [new Application/Traffic/CBR]

$discover1 set packetSize_ 500

$discover1 set interval_ 1.0  ;# Simulate DHCP request from client1

$discover1 attach-agent $udp_client1

set discover2 [new Application/Traffic/CBR]

$discover2 set packetSize_ 500

$discover2 set interval_ 1.5  ;# Simulate DHCP request from client2

$discover2 attach-agent $udp_client2

# Start DHCP discovery process

$ns at 0.5 “$discover1 start”

$ns at 1.0 “$discover2 start”

# Stop DHCP discovery after some time

$ns at 4.0 “$discover1 stop”

$ns at 4.5 “$discover2 stop”

# End simulation at 5 seconds

$ns at 5.0 “finish”

proc finish {} {

global ns tracefile

$ns flush-trace

close $tracefile

exit 0

}

# Run the simulation

$ns run

Explanation:

  • DHCP Server Simulation: The node dhcp_server replicates a DHCP server that dynamically allots IP addresses from an IP pool to client nodes (client1 and client2).
  • Client Nodes: client1 and client2 simulate devices requesting IP addresses from the DHCP server.
  • IP Assignment: While real IP addresses are not assigned in NS2, we mimic the activities of allocating 192.168.1.1 to client1 and 192.168.1.2 to client2.
  • Traffic Flow: CBR traffic imitates DHCP messages like DHCP Discover (from clients) and DHCP Acknowledgment (from the server).
  1. Simulating DHCP Lease Process

To simulate the full DHCP process (such as discovery, offer, request, and acknowledgment):

  • DHCP Discovery (DHCPDISCOVER): The client sends a request for an IP address.
  • DHCP Offer (DHCPOFFER): The server provides an existed IP address.
  • DHCP Request (DHCPREQUEST): The client requests the offered IP address.
  • DHCP Acknowledgment (DHCPACK): The server verifies the lease of the IP address.

In this simulation, the CBR traffic indicates the DHCP Discover and Ack messages.

  1. Monitor DHCP Events

NS2’s trace file logs the communication amongst clients and the DHCP server. You can track the DHCP-related events like when a client requests an IP address and when the server reacts.

  1. Calculate Key DHCP Management Metrics

DHCP Lease Time

The DHCP lease time is the duration for which a client holds an IP address before it must renovate the lease. You can track the time from when the server allots the IP address to the client until the lease terminates.

Here’s an AWK script to measure the DHCP lease time:

awk ‘

{

if ($1 == “+” && $3 == “client1”) {  # DHCP request sent from client1

if (lease_start_client1 == 0) {

lease_start_client1 = $2;  # Record the time of lease start

}

}

if ($1 == “r” && $3 == “client1”) {  # IP address acknowledgment received by client1

lease_end_client1 = $2;  # Record the end time of the lease

}

}

END {

lease_time_client1 = lease_end_client1 – lease_start_client1;

print “DHCP Lease Time for client1:”, lease_time_client1, “seconds”;

}’ dhcp_management_trace.tr

This script computes how long client1 holds the allocated IP address before the lease ends.

DHCP Request Response Time

The DHCP request response time measures how fastly the DHCP server reacts to a client’s IP address request. It is the time amongst the client’s DHCP Discover message and the server’s DHCP Ack message.

Here’s an AWK script to calculate DHCP request response time:

awk ‘

{

if ($1 == “+” && $3 == “client1”) {  # DHCP request sent from client1

send_time[$7] = $2;  # Record the time of the DHCP request

}

if ($1 == “r” && $3 == “client1”) {  # DHCP acknowledgment received by client1

response_time = $2 – send_time[$7];  # Calculate the response time

print “DHCP Request Response Time for client1:”, response_time, “seconds”;

}

}’ dhcp_management_trace.tr

This script calculates how rapidly the server responds to client1’s DHCP request.

DHCP Server Load

The DHCP server load can be calculated by summing up the amount of requests processed by the server over time. This gives insight into how much traffic the DHCP server is managing and whether it can efficiently handle numerous clients.

Here’s an AWK script to calculate the DHCP server load:

awk ‘

{

if ($1 == “r” && $3 == “dhcp_server”) {  # DHCP request received by DHCP server

dhcp_queries_handled++;

}

}

END {

print “Total DHCP Requests Handled by DHCP Server:”, dhcp_queries_handled;

}’ dhcp_management_trace.tr

This script tracks how many DHCP requests the server processes during the simulation.

IP Address Utilization

The IP address utilization metric tracks how many IP addresses are allotted from the pool and how efficiently they are used by clients. In a more advanced simulation, you could observe which IP addresses are in use and when they are released.

  1. Simulate DHCP Lease Renewal

In addition to the initial IP assignment, you can mimic DHCP lease renewal where clients occasionally request to renew their IP address lease before it expires. This would encompass clients sending DHCP Request messages to extend their lease and the server reacting with DHCP Ack.

  1. Visualize DHCP Metrics

Once the DHCP metrics is measured, you can use python (matplotlib) to visualize and analyze DHCP performance includes lease times, response times, and server load.

Example Python Plot for DHCP Response Time:

import matplotlib.pyplot as plt

# Example data for DHCP response times

clients = [‘client1’, ‘client2’]

response_times = [0.03, 0.05]  # Example response times in seconds

plt.bar(clients, response_times)

plt.title(‘DHCP Request Response Time’)

plt.xlabel(‘Clients’)

plt.ylabel(‘Response Time (seconds)’)

plt.show()

Summary

To measures network DHCP management in NS2:

  1. Set up the simulation: Designate nodes as DHCP clients and servers. Use CBR traffic to mimic DHCP requests and acknowledgments.
  2. Monitor DHCP events: Track requests and responses amongst clients and the server in the trace file.
  3. Calculate key metrics: AWK script is used to estimate DHCP lease time, request response time, server load, and IP address consumption.
  4. Simulate lease renewals: Extend the simulation to manage DHCP lease renewal.
  5. Visualize results: Plot DHCP metrics like response times and server load using Python or similar tools.

The above manual offers the detailed information and examples to guide you with the calculation of Network Dynamic Host Configuration Protocol (DHCP) in the NS2 simulation. We plan to deliver any other details of DHCP or ns2 through another module.

For customized Network DHCP Management in the NS2 tool, reach out to us for exceptional results. Provide us with your parameter details, and we will assist you effectively.