How to Start Grid Topology Projects Using NS2

To replicate a Grid Topology in NS2 (Network Simulator 2) has includes the build a node for organized the 2D grid architecture. This topology is generally used for model environment such as wireless sensor networks, IoT deployments, or structured network layouts for performance analysis.

Here’s a guide to start your Grid Topology project in NS2:

Steps to Simulate Grid Topology in NS2

  1. Understand Grid Topology
  • Structure:
    • Nodes are placed in a grid-like procedure, by every node has linked to the neighbor such us up, down, left, right.
    • Describe the design for grid dimensions (rows × columns).
  • Applications:
    • Wireless sensor networks.
    • IoT deployments for smart cities.
    • Research the multi hop communication.
  1. Set Up NS2
  1. Install NS2:

sudo apt-get install ns2

  1. Verify Installation: Validate through a basic replication of script:

ns example.tcl

  1. Define Grid Topology
  • Require the number of rows and columns for the grid.
  • Link the nodes for immediate neighbor in form a designed grid.
  1. TCL Script for Grid Topology

Under the sample script for replicating the Grid Topology:

TCL Script Example

# Initialize NS2 Simulator

set ns [new Simulator]

set tracefile [open grid_topology.tr w]

$ns trace-all $tracefile

# Grid dimensions

set rows 3

set cols 3

set num_nodes [expr $rows * $cols]

# Create nodes and store their references in an array

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

set n($i) [$ns node]

}

# Create grid links

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

for {set j 0} {$j < $cols} {incr j} {

set index [expr $i * $cols + $j]

# Connect to right neighbor

if {$j < [expr $cols – 1]} {

set right [expr $index + 1]

$ns duplex-link $n($index) $n($right) 1Mb 10ms DropTail

}

# Connect to bottom neighbor

if {$i < [expr $rows – 1]} {

set bottom [expr $index + $cols]

$ns duplex-link $n($index) $n($bottom) 1Mb 10ms DropTail

}

}

}

# Attach agents to simulate traffic

# Example: Traffic from top-left node to bottom-right node

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:
    • Data broadcasts with the grid structure.
    • Follow on the multi-hop transmission through intermediate nodes.
  2. Performance Metrics:
    • Throughput: Calculate the data delivery with the grid.
    • Latency: Examine the delays for congestion traversing several nodes.
    • Packet Loss: Estimate the network reliability.
  1. Analyze Trace File
  • Use the trace file (grid_topology.tr) for specific investigation.
  • Excerpt detailed performance of parameter metrics:
    • Throughput:

grep “tcp” grid_topology.tr > throughput.log

    • Dropped Packets:

grep “drop” grid_topology.tr > dropped_packets.log

  1. Visualize Result:

Use Gnuplot or another envision tool:

  1. Throughput Graph:

set title “Grid Topology Throughput”

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

  1. Latency Graph:
    • Associate the delays for congestion with several grid paths.
  1. Extend the Simulation
  2. Dynamic Traffic Patterns
  • Enhance the further congestion flows among the random nodes.

set udp0 [new Agent/UDP]

$ns attach-agent $n(4) $udp0

set null0 [new Agent/Null]

$ns attach-agent $n(7) $null0

$ns connect $udp0 $null0

  1. Simulate Node Failures
  • Replicate the node or connection failures for examine the network resilience:

$ns at 2.5 “$ns reset-links $n(1) $n(4)”

  1. Experiment with Protocols
  • Exchange the protocol for TCP by UDP and associate the performance:

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

For advanced scenarios:

  1. Custom Node Behavior:
    • Execute the specific logic in the recv() technique for intermediate nodes.
  2. Dynamic Topology:
    • Improve or eliminate the nodes are during the replication for dynamically:

$ns at 3.0 “$ns duplex-link $n(8) $n(9) 1Mb 10ms DropTail”

The above the complete project about grid topology that was simulated and implemented using ns2 tool and it has encompass the sample codes, detailed explanation about coding and provide the performance analysis regarding this project. Additional details will be added later.