How to Start Partial Mesh Topology Projects Using NS2

To start simulating a Partial Mesh Topology within NS2 (Network Simulator 2) that requires making a network in which some nodes are associated whereas others depend on the intermediary nodes for interaction. This topology equalizes the connectivity and cost-effectiveness to create it which is appropriate for scenarios such as wireless sensor networks or small office networks.

Below is an in-depth process to get started Partial Mesh Topology project in NS2:

Steps to Start Partial Mesh Topology in NS2

  1. Understand Partial Mesh Topology
  • Structure:
    • It has only a subset of nodes that is completely associated.
    • Other nodes depend on the certain intermediary nodes to interact.
  • Applications:
    • It is appropriate for scenarios such as wireless sensor networks, IoT, or small LANs including restricted interconnectivity.
  • Advantages:
    • Minimizes the cost of complete connectivity.
    • It sustains redundancy for critical nodes.
  1. Set Up NS2
  1. Install NS2: We should install the NS2 environment on the system.

sudo apt-get install ns2

  1. Verify Installation: Confirm installation including an example simulation script:

ns example.tcl

  1. Define Partial Mesh Topology
  • Make a partial mesh topology that contains nodes with both direct and indirect connections.
  • Example:
    • Direct Connections: Nodes n0, n1, and n2 are completely interconnected.
    • Indirect Connections: Nodes n3 and n4 interact through n1 or n2.
  1. TCL Script for Partial Mesh Topology

Below is a sample tcl script in NS2:

TCL Script Example

# Initialize NS2 Simulator

set ns [new Simulator]

set tracefile [open partial_mesh_topology.tr w]

$ns trace-all $tracefile

# Create nodes

set n0 [$ns node]

set n1 [$ns node]

set n2 [$ns node]

set n3 [$ns node]

set n4 [$ns node]

# Create direct links (fully connected subset)

$ns duplex-link $n0 $n1 1Mb 10ms DropTail

$ns duplex-link $n1 $n2 1Mb 10ms DropTail

$ns duplex-link $n0 $n2 1Mb 10ms DropTail

# Create indirect links

$ns duplex-link $n1 $n3 512Kb 20ms DropTail

$ns duplex-link $n2 $n4 512Kb 20ms DropTail

# Attach agents to simulate traffic

# Traffic from n0 to n4 via n2

set tcp0 [new Agent/TCP]

$ns attach-agent $n0 $tcp0

set sink0 [new Agent/TCPSink]

$ns attach-agent $n4 $sink0

$ns connect $tcp0 $sink0

# Traffic from n3 to n2

set udp0 [new Agent/UDP]

$ns attach-agent $n3 $udp0

set null0 [new Agent/Null]

$ns attach-agent $n2 $null0

$ns connect $udp0 $null0

# Add traffic generators

set ftp [new Application/FTP]

$ftp attach-agent $tcp0

set cbr [new Application/Traffic/CBR]

$cbr set packetSize_ 512

$cbr set interval_ 0.1

$cbr attach-agent $udp0

# Start traffic

$ns at 1.0 “$ftp start”

$ns at 1.5 “$cbr 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:
    • Make sure that data properly passes through direct and indirect paths.
  2. Performance Metrics:
    • Throughput: Estimate the rate of data delivery for direct and indirect connections.
    • Latency: Examine delay variances among the direct and indirect paths.
    • Packet Loss: Measure reliability within less connected nodes.
  1. Analyze Trace File
  • To examine the performance parameters, we can utilise the trace file as partial_mesh_topology.tr.
  • Obtain certain performance indicators such as:
    • Throughput:

grep “tcp” partial_mesh_topology.tr > throughput.log

    • Dropped Packets:

grep “drop” partial_mesh_topology.tr > dropped_packets.log

  1. Visualize Results

Make use of Gnuplot or another plotting tool for envisioning:

  1. Throughput Graph:

set title “Partial Mesh Throughput”

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

  1. Latency Graph:
    • Equate the delays on direct and indirect paths for traffic.
  1. Extend the Simulation
  2. Simulate Fault Tolerance
  • Mimic node or link failures and then monitor the behaviour of rerouting:

$ns at 2.5 “$ns reset-links $n1 $n2”

  1. Experiment with Traffic Patterns
  • Integrate the traffic among other nodes to experiment simultaneous interaction.

set udp1 [new Agent/UDP]

$ns attach-agent $n3 $udp1

set null1 [new Agent/Null]

$ns attach-agent $n0 $null1

$ns connect $udp1 $null1

  1. Add QoS Requirements
  • Replicate the priority-based traffic for assessing quality of service.
  1. Simulate Advanced Protocols
  • Experiment the routing protocols such as AODV or DSR in partial mesh topology for dynamic routing.
  1. Modify NS2 Core for Advanced Features

For advanced aspects of partial mesh topology, we can:

  1. Dynamic Topology:
    • During the simulation, replicate the dynamic node links in the topology.

$ns at 3.0 “$ns duplex-link $n3 $n4 512Kb 20ms DropTail”

  1. Custom Node Behavior:
    • Execute certain packet handling logic for intermediate nodes within recv().

The NS2 environment enabled to perform the simulation process that containing key concepts with sample coding and further functionalities of Partial Mesh Topology projects. We’re able to provide more updated information related to this projects, if necessary.