How to Start Wireless Mesh Topology Projects Using NS2

To start a Wireless Mesh Topology project using NS2 (Network Simulator 2), it has contains replicating a network in which nodes (routers and clients) are linked within a mesh-like structure. This topology offers robust, scalable, and redundant interaction for urban networks, IoT systems, and disaster retrieval.

Below is a series of steps on how to replicate a Wireless Mesh Topology project in NS2:

Steps to Start Wireless Mesh Topology Projects in NS2

1. Understand Wireless Mesh Topology

• Wireless Mesh Topology:
  • Nodes interact through wireless links to build a mesh structure.
  • Every single node can perform like a router for transmitting traffic to other nodes.
• Key Features:
  • Scalable and flexible.
  • Self-healing: It can redirect traffic as a link drops.
  • Redundancy and reliability by reason of numerous routes.
• Applications:
  • Industrial IoT systems.
  • Wireless sensor networks.
  • Community networks.

2. Set Up NS2

1. Install NS2:
   • We should set up and confirm the NS2 functionality:

ns example.tcl

1. Tools for Analysis:
   • NAM (Network Animator) is intended for visualization.
   • Trace Analysis Tools supports to estimate the performance parameters such as throughput, latency, and packet delivery ratio.

3. Plan the Wireless Mesh Topology

• Network Design:
  • Locate the nodes within a grid or random distribution for replicating a mesh network.
  • Allow multi-hop communication to transmit via intermediate nodes.
• Traffic Pattern:
  • Peer-to-peer communication among the chosen nodes arbitrarily.
• Metrics to Analyze:
  • Latency.
  • Throughput.
  • Packet delivery ratio (PDR).

4. Write the Simulation Script

Step 4.1: Create the TCL Script

We will store the simulation tcl script like wireless_mesh_topology.tcl.

Step 4.2: Initialize the Simulator

We can start to configure the wireless simulator:

# Create simulator instance

set ns [new Simulator]

set tracefile [open trace.tr w]

$ns trace-all $tracefile

set namfile [open wireless_mesh_topology.nam w]

$ns namtrace-all-wireless $namfile

# Define the topology parameters

set val(chan) Channel/WirelessChannel

set val(prop) Propagation/TwoRayGround

set val(ant) Antenna/OmniAntenna

set val(ll) LL

set val(ifq) Queue/DropTail/PriQueue

set val(ifqlen) 50

set val(netif) Phy/WirelessPhy

set val(mac) Mac/802_11

set val(x) 500

set val(y) 500

set val(seed) 0.0

Step 4.3: Create Nodes

• Describe the wireless nodes and set its locations:

# Set up the wireless topology

set val(nn) 9   ;# Number of nodes in the mesh

# Create wireless nodes

for {set i 0} {$i < $val(nn)} {incr i} {

set node_($i) [$ns node]

$node_($i) random-motion 0 ;# Disable random motion

}

# Set node positions (Grid Layout)

set positions {

{100 100} {200 100} {300 100}

{100 200} {200 200} {300 200}

{100 300} {200 300} {300 300}

}

set idx 0

foreach pos $positions {

set x [lindex $pos 0]

set y [lindex $pos 1]

$node_($idx) set X_ $x

$node_($idx) set Y_ $y

$node_($idx) set Z_ 0.0

incr idx

}

Step 4.4: Configure Traffic

• Configure the flows of peer-to-peer traffic:

# Traffic from node_0 to node_8

set udp1 [new Agent/UDP]

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

set null1 [new Agent/Null]

$ns attach-agent $node_(8) $null1

$ns connect $udp1 $null1

set cbr1 [new Application/Traffic/CBR]

$cbr1 attach-agent $udp1

$cbr1 set packetSize_ 512

$cbr1 set rate_ 50kb

$ns at 1.0 “$cbr1 start”

# Traffic from node_1 to node_7

set udp2 [new Agent/UDP]

$ns attach-agent $node_(1) $udp2

set null2 [new Agent/Null]

$ns attach-agent $node_(7) $null2

$ns connect $udp2 $null2

set cbr2 [new Application/Traffic/CBR]

$cbr2 attach-agent $udp2

$cbr2 set packetSize_ 512

$cbr2 set rate_ 50kb

$ns at 2.0 “$cbr2 start”

Step 4.5: Enable Routing Protocol

• Make use of routing protocols like AODV or DSDV for the mesh topology:

# Enable AODV Routing Protocol

$ns rtproto AODV

Step 4.6: Finalize the Script

• We will want to integrate the simulation end and visualization configuration to finish the script:

# Simulation end

$ns at 10.0 “finish”

proc finish {} {

global ns tracefile namfile

$ns flush-trace

close $tracefile

close $namfile

exec nam wireless_mesh_topology.nam &

exit 0

}

$ns run

5. Run the Simulation

1. We need to store the tcl simulation script like wireless_mesh_topology.tcl.
2. Then, run the simulation with NS2:

ns wireless_mesh_topology.tcl

1. Go to NAM for envisioning the mesh topology:

nam wireless_mesh_topology.nam

6. Analyze Results

• Trace File Analysis:
  • Measure the performance indicators such as throughput, latency, and PDR utilising trace.tr.
  • Example AWK script for computing the throughput:

awk ‘{if ($1 == “r” && $4 == “udp”) sum += $8} END {print “Throughput: “, sum}’

• Metrics:
  • Packet Delivery Ratio (PDR): Estimate the reliability of the network.
  • Latency: Examine delays within interaction.
  • Throughput: Measure the data delivery effectiveness.

7. Expand the Simulation

1. Simulate Node Failures:
   • Launch node or link failures to experiment the resilience of network:

$ns at 5.0 “$ns link-fail $node_(3) $node_(4)”

1. Vary Traffic Patterns:
   • Integrate the TCP traffic models or maximize the traffic intensity.
2. Experiment with Mobility:
   • Allow node mobility for mimicking dynamic mesh networks.
3. Compare Routing Protocols:
   • We will substitute the routing protocols such as AODV with DSDV or DSR and examine their performance.

8. Document the Project

• Objective: Define the project’s goals of replicating a wireless mesh topology.
• Setup: Specify node placement, traffic models, and routing protocols.
• Results: It has performance parameters such as throughput, latency, and PDR.
• Conclusions: Sum up outcomes and it recommends enhancement.

In this module, we acquire the essential information elaborately regarding how the Wireless Mesh Topology will execute and simulate using NS2 platform. We will deliver more information on this topic based on your needs.