How to Calculate Network Segmentation in NS2

To calculate the Network segmentation in ns2 has need defined to dividing a network into smaller segments or subnets to enhance security, performance, and manageability. In NS2 network segmentation can be mimicked by generating multiple subnets, implement routing rules to regulate traffic between them, and evaluating the performance of traffic flows through segments. To ensure full project support, simply provide us with your requirements, and we will assist you in achieving the best project results.

To estimate and measure network segmentation in NS2, we can simulate the following:

  1. Multiple subnets (segments) with routers associating them.
  2. Traffic flows between segments.
  3. Performance metrics like latency, throughput, packet loss, and security.

Steps to Simulate and Calculate Network Segmentation in NS2

  1. Set Up Multiple Segments (Subnets) in NS2

In this case, we will simulate two network segments:

  • Segment 1: Contains nodes in subnet 1.
  • Segment 2: Contains nodes in subnet 2.
  • Router: Associates the two segments and manage inter-segment communication.

Example NS2 Script for Network Segmentation

# Create NS2 simulator instance

set ns [new Simulator]

# Open trace file for output

set tracefile [open out.tr w]

$ns trace-all $tracefile

# Define nodes in Segment 1

set seg1_router [$ns node]   ;# Router for Segment 1

set seg1_node1 [$ns node]    ;# Node in Segment 1

set seg1_node2 [$ns node]    ;# Node in Segment 1

# Define nodes in Segment 2

set seg2_router [$ns node]   ;# Router for Segment 2

set seg2_node1 [$ns node]    ;# Node in Segment 2

set seg2_node2 [$ns node]    ;# Node in Segment 2

# Create links within Segment 1 (Segment 1 Router to nodes)

$ns duplex-link $seg1_router $seg1_node1 1Mb 10ms DropTail

$ns duplex-link $seg1_router $seg1_node2 1Mb 10ms DropTail

# Create links within Segment 2 (Segment 2 Router to nodes)

$ns duplex-link $seg2_router $seg2_node1 1Mb 10ms DropTail

$ns duplex-link $seg2_router $seg2_node2 1Mb 10ms DropTail

# Create link between the two segments (Router to Router)

$ns duplex-link $seg1_router $seg2_router 1Mb 20ms DropTail  ;# Longer delay simulates inter-segment traffic

# Set up UDP traffic from Segment 1 to Segment 2

set udp1 [new Agent/UDP]

$ns attach-agent $seg1_node1 $udp1

set null1 [new Agent/Null]

$ns attach-agent $seg2_node1 $null1

$ns connect $udp1 $null1

set cbr1 [new Application/Traffic/CBR]

$cbr1 set packetSize_ 500

$cbr1 set interval_ 0.01

$cbr1 attach-agent $udp1

# Set up UDP traffic from Segment 2 to Segment 1

set udp2 [new Agent/UDP]

$ns attach-agent $seg2_node2 $udp2

set null2 [new Agent/Null]

$ns attach-agent $seg1_node2 $null2

$ns connect $udp2 $null2

set cbr2 [new Application/Traffic/CBR]

$cbr2 set packetSize_ 500

$cbr2 set interval_ 0.01

$cbr2 attach-agent $udp2

# Start and stop traffic

$ns at 0.5 “$cbr1 start”

$ns at 0.5 “$cbr2 start”

$ns at 4.5 “$cbr1 stop”

$ns at 4.5 “$cbr2 stop”

# End simulation

$ns at 5.0 “finish”

proc finish {} {

global ns tracefile

$ns flush-trace

close $tracefile

exit 0

}

# Run the simulation

$ns run

Explanation of the Script:

  • Segments: We describe two segments, each with its own router and two nodes.
  • Inter-segment Link: A link among the two routers mimics communication among the segments.
  • Traffic: Traffic flows from Segment 1 to Segment 2 and vice versa, that mimics inter-segment communication.
  1. Simulate Network Segmentation with Traffic Rules

We can apply rules to control the traffic among the segments. For example, we can implement filtering rules to block or limit traffic among the segments, which mimics firewall rules.

Example: Blocking Specific Traffic between Segments

We can describe a traffic filter which blocks particular traffic among the two segments.

# Define traffic filtering rule (Block UDP traffic from Segment 1 to Segment 2)

proc traffic_filter {src dst type} {

if {$src == “seg1_node1” && $dst == “seg2_node1” && $type == “UDP”} {

return 0  ;# Block the traffic

}

return 1  ;# Allow all other traffic

}

# Apply the filter to restrict traffic between the segments

$ns at 0.5 “$ns set-forwarding-filter traffic_filter”

This filter blocks UDP traffic from seg1_node1 to seg2_node1.

  1. Capture Data from the Trace File

NS2 creates a trace file (out.tr) that logs packet transmission, drops, and other network events. This file can be measured to estimate the parameters related to network segmentation such as:

  • Latency between segments.
  • Throughput within and between segments.
  • Packet loss due to segmentation rules or congestion.
  1. Calculate Network Segmentation Metrics

Latency Between Segments

Latency is defined to the time it takes for packets to travel from one segment to another. We can compute the delay by evaluating the difference among the time a packet leaves the source and the time it arrives at the destination.

Here’s an AWK script to estimate the average inter-segment latency:

awk ‘

{

if ($1 == “+”) {

send_time[$7] = $2;  # Record the send time from Segment 1

}

if ($1 == “-” && $3 == “seg2_node1”) {

if (send_time[$7] != “”) {

latency = $2 – send_time[$7];  # Calculate latency between segments

total_latency += latency;

count++;

}

}

}

END { print “Average Inter-Segment Latency:”, total_latency / count, “seconds”; }’ out.tr

This script estimates the average latency for traffic among Segment 1 and Segment 2.

Throughput between Segments

Throughput defined to the amount of data successfully routed among the segments. We can estimate throughput by counting the bytes forwarded among segments.

Here’s an AWK script to estimate the throughput among segments:

awk ‘

{

if ($1 == “-” && $3 == “seg1_router” && $4 == “seg2_router”) {

total_bytes += $6;  # Sum the total bytes transmitted between the segments

}

}

END { print “Throughput Between Segments:”, total_bytes / 5.0, “bytes/sec”; }’ out.tr

This script estimates the throughput by counting the total bytes forwarded among the routers of Segment 1 and Segment 2, then dividing by the simulation time (5 seconds).

Packet Loss Due to Segmentation

Packet loss can happen because of network congestion, segmentation rules, or firewall filters. We can estimate packet loss by counting the d (drop) events in the trace file.

Here’s an AWK script to calculate packet loss:

awk ‘

{

if ($1 == “d” && $3 == “seg1_router”) {  # Count drops at the router between segments

dropped_packets++;

}

}

END { print “Total Packets Dropped Between Segments:”, dropped_packets; }’ out.tr

This script sums up how many packets were dropped by the router because of segmentation or filtering.

  1. Enhance Network Segmentation

We can improve network segmentation by executing more advanced routing, filtering, or Quality of Service (QoS) policies. For example:

  • Implement VLANs: we can mimic diverse VLANs by describing strict routing rules among diverse segments.
  • Simulate security policies: Implement diverse access control lists (ACLs) or firewall rules to regulate traffic among different subnets.
  1. Visualize Network Segmentation Performance

We can envision parameters such as throughput, latency, and packet loss using tools such as Python (matplotlib) or Excel. Here’s an instance of how to plot the throughput among segments over time.

Example Python Plot for Throughput:

import matplotlib.pyplot as plt

# Example data for throughput between segments over time

time = [0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5]

throughput = [400, 450, 470, 490, 500, 510, 520, 530, 540]  # Example throughput data (bytes/sec)

plt.plot(time, throughput, marker=’o’)

plt.title(‘Throughput Between Segments Over Time’)

plt.xlabel(‘Time (seconds)’)

plt.ylabel(‘Throughput (bytes/sec)’)

plt.grid(True)

plt.show()

Summary

To simulate and estimate network segmentation in NS2:

  1. Set up the simulation: Describe multiple segments (subnets) and routers associating them.
  2. Implement segmentation policies: Implement traffic filtering, routing rules, and segmentation policies among subnets.
  3. Capture trace data: measure the trace file to estimate parameters such as latency, throughput, and packet loss.
  4. Enhance segmentation: Mimic more advanced segmentation by adding security policies or replicating VLANs.
  5. Visualize performance: Utilize tools such as Python to plot and measure the performance of segmented networks.

The detailed guide contains the expounded manual that will support you with the computation of Network segmentation in the ns2 environment by creating multiple subnets, apply the routing rules, and analysing the performance through segments and it also provides some samples. We plan deliver more information regarding the Network segmentation.