How to Start Line Topology Projects Using NS2

To stimulate a Line Topology in NS2 (Network Simulator 2) has includes the organizing nodes in setting of linear in which every node is linked to the immediate neighbor(s). Data travels from one end to other line or among the intermediate nodes, create it appropriate for investigate the sequential transmission, delay for the broadcast and multi-hop environment.

Here’s how to start your Line Topology project in NS2:

Steps to Simulate Line Topology in NS2

  1. Understand Line Topology
  • Structure:
    • Nodes are linked in sequentially for a straight line.
    • Data typically travels with several hops.
  • Applications:
    • Communication systems for linear.
    • Multi-hop wireless networks.
    • Sensor networks are deployed beside of linear paths for sample pipelines, roads.
  1. Set Up NS2
  1. Install NS2:

sudo apt-get install ns2

  1. Verify Installation: validate by a simple script:

ns example.tcl

  1. Define Line Topology
  • Generate a detailed number of nodes.
  • Linked the every node for immediate neighbor, forming a straight-line setting.
  1. TCL Script for Line Topology

Under is an sample of script for replicate a Line Topology:

TCL Script Example

# Initialize NS2 Simulator

set ns [new Simulator]

set tracefile [open line_topology.tr w]

$ns trace-all $tracefile

# Define number of nodes

set num_nodes 5

 

# Create nodes

for {set i 0} {$i < $num_nodes} {incr i} {

set n($i) [$ns node]

}

# Create links between nodes to form a line

for {set i 0} {$i < [expr $num_nodes – 1]} {incr i} {

set next [expr $i + 1]

$ns duplex-link $n($i) $n($next) 1Mb 10ms DropTail

}

# Attach agents for traffic simulation

# Example: Traffic from n0 to n(num_nodes-1)

set tcp0 [new Agent/TCP]

$ns attach-agent $n(0) $tcp0

set sink0 [new Agent/TCPSink]

$ns attach-agent $n([expr $num_nodes – 1]) $sink0

$ns connect $tcp0 $sink0

# Add a traffic generator

set ftp [new Application/FTP]

$ftp attach-agent $tcp0

# Start traffic

$ns at 1.0 “$ftp start”

# End simulation

$ns at 5.0 “finish”

proc finish {} {

global ns tracefile

$ns flush-trace

close $tracefile

exit 0

}

$ns run

  1. Key Features to Simulate
  1. Traffic Flow:
    • The data broadcast with intermediate nodes for congestion flow.
    • Follow on the delays as packets travel form several hops.
  2. Performance Metrics:
    • Throughput: Calculate the data delivery for the end node.
    • Latency: Examine the delays among source and destination.
    • Packet Loss: Estimate the reliability in multi-hop environment.
  1. Analyze Trace File
  • Use the trace file such as line_topology.tr for study the network performance.
  • Excerpt the detailed performance of metrics:
    • Throughput:

grep “tcp” line_topology.tr > throughput.log

    • Dropped Packets:

grep “drop” line_topology.tr > dropped_packets.log

  1. Visualize Results

Use the outcomes for Gnuplot or additional envision tool:

  1. Throughput Graph:

set title “Line Topology Throughput”

plot “throughput.log” using 1:2 with lines title “Throughput”

  1. Latency Graph:
    • It associates the delays for congestion traversing change the numbers of hops.
  1. Extend the Simulation
  2. Simulate Bi-Directional Communication
  • Improve the agents for reverse congestion:

set tcp1 [new Agent/TCP]

$ns attach-agent $n([expr $num_nodes – 1]) $tcp1

set sink1 [new Agent/TCPSink]

$ns attach-agent $n(0) $sink1

$ns connect $tcp1 $sink1

  1. Test Different Traffic Patterns
  • Improve the congestion among intermediate nodes:

set udp0 [new Agent/UDP]

$ns attach-agent $n(1) $udp0

set null0 [new Agent/Null]

$ns attach-agent $n(3) $null0

$ns connect $udp0 $null0

  1. Simulate Node Failures
  • It replicate the failures for intermediate nodes in following the effect:

$ns at 2.5 “$ns reset-links $n(2) $n(3)”

  1. Compare TCP vs UDP
  • It replicate the UDP congestion and associate by performance of TCP:

set udp1 [new Agent/UDP]

$ns attach-agent $n(0) $udp1

set null1 [new Agent/Null]

$ns attach-agent $n([expr $num_nodes – 1]) $null1

$ns connect $udp1 $null1

  1. Modify NS2 Core for Advanced Features

Designed for advanced environment:

  1. Dynamic Node Behavior:
    • We replicates the dynamic addition or elimination of nodes:

$ns at 3.0 “$ns duplex-link $n(4) $n(5) 1Mb 10ms DropTail”

  1. Custom Node Logic:
    • Change the recv() techniques in the key C++ code for maintain the detailed packet forwarding or need for the processing.

This setup will permit to compute and measure the Line topology in ns2 simulation that delivers the valuable insights on how the nodes are changes in the immediate neighbor. If you have any query regarding the line topology, we will help to clarify it.