How to Implement Ring Mesh Hybrid Topology in NS2

To implement a Ring-Mesh Hybrid Topology in Network Simulator 2 (NS2), has series of steps to follow that includes to incorporate the features of a ring topology and a mesh topology. In this type of network:

  • A ring topology is formed in which the nodes are associated in a circular structure, meaning each node has two neighbours (one on either side).
  • A mesh topology is added, that certain nodes in the ring are associated then deliver, additional direct links among them for redundancy or enhanced performance.

Steps to Implement Ring-Mesh Hybrid Topology in NS2

  1. Set up NS2

Make sure that NS2 is installed on the system. If not, install it using the following command on Linux/Ubuntu:

sudo apt-get update

sudo apt-get install ns2

  1. Define the Ring-Mesh Hybrid Topology
  • In the ring topology, nodes are associated to exactly two other nodes (forming a circular network).
  • In the mesh topology, additional links are added among the non-adjacent nodes, delivering more paths for interaction.
  1. Create a TCL Script for Ring-Mesh Hybrid Topology

The following is an example TCL script for a Ring-Mesh Hybrid Topology with six nodes. A ring topology connects all the nodes in a circular manner, while mesh-like connections add extra links between non-adjacent nodes for redundancy.

Example TCL Script for Ring-Mesh Hybrid Topology:

# Define the simulator

set ns [new Simulator]

# Open trace files

set tracefile [open ring_mesh_out.tr w]

set namfile [open ring_mesh_out.nam w]

$ns trace-all $tracefile

$ns namtrace-all $namfile

# Create a topography object for layout

set topo [new Topography]

$topo load_flatgrid 500 500

# Create a channel for wired links

set chan [new Channel/WiredChannel]

# Define nodes in the ring-mesh hybrid topology

set node_0 [$ns node]

set node_1 [$ns node]

set node_2 [$ns node]

set node_3 [$ns node]

set node_4 [$ns node]

set node_5 [$ns node]

# Position the nodes in a circular (ring) layout

$node_0 set X_ 200.0

$node_0 set Y_ 300.0

$node_1 set X_ 300.0

$node_1 set Y_ 250.0

$node_2 set X_ 300.0

$node_2 set Y_ 150.0

$node_3 set X_ 200.0

$node_3 set Y_ 100.0

$node_4 set X_ 100.0

$node_4 set Y_ 150.0

$node_5 set X_ 100.0

$node_5 set Y_ 250.0

# Connect nodes in a ring topology (each node connects to two neighbors)

$ns duplex-link $node_0 $node_1 100Mb 10ms DropTail

$ns duplex-link $node_1 $node_2 100Mb 10ms DropTail

$ns duplex-link $node_2 $node_3 100Mb 10ms DropTail

$ns duplex-link $node_3 $node_4 100Mb 10ms DropTail

$ns duplex-link $node_4 $node_5 100Mb 10ms DropTail

$ns duplex-link $node_5 $node_0 100Mb 10ms DropTail

# Add extra links (mesh) between non-adjacent nodes for redundancy

$ns duplex-link $node_0 $node_2 100Mb 15ms DropTail

$ns duplex-link $node_1 $node_3 100Mb 15ms DropTail

$ns duplex-link $node_4 $node_0 100Mb 15ms DropTail

# Setup traffic flow between nodes

# Traffic from node_0 to node_3

set udp0 [new Agent/UDP]

set null0 [new Agent/Null]

$ns attach-agent $node_0 $udp0

$ns attach-agent $node_3 $null0

$ns connect $udp0 $null0

# Create CBR (Constant Bit Rate) traffic

set cbr0 [new Application/Traffic/CBR]

$cbr0 set packetSize_ 512

$cbr0 set interval_ 0.05

$cbr0 attach-agent $udp0

# Start traffic at time 1.0 second

$ns at 1.0 “$cbr0 start”

# Schedule simulation end

$ns at 10.0 “finish”

# Finish procedure to close the simulation

proc finish {} {

global ns tracefile namfile

$ns flush-trace

close $tracefile

close $namfile

exec nam ring_mesh_out.nam &

exit 0

}

# Run the simulation

$ns run

Explanation of the Script:

  1. Node Creation and Positioning:
    • The script generates six nodes (node_0 to node_5) positioned in a circular layout to form the ring topology. These nodes are positioned in a circle using set X_ and set Y_ to visually form a ring in the simulation.
  2. Ring Topology Links:
    • The nodes are associated in a ring, in which each node connects to two neighbours. For instance, node_0 is connected to node_1 and node_5.
  3. Mesh Links:
    • Additional links (forming the mesh topology) are generated among non-adjacent nodes. These links deliver more paths for communication and add redundancy. For instance, node_0 is connected directly to node_2, node_1 is connected to node_3, and node_4 is connected to node_0.
  4. Traffic Setup:
    • Traffic is configuring among node_0 and node_3. A UDP agent is involved to node_0, and a null agent is attached to node_3. A CBR (Constant Bit Rate) traffic generator is used to make traffic among these two nodes.
  5. Trace and NAM Visualization:
    • The simulation creates trace files (ring_mesh_out.tr) and a NAM file (ring_mesh_out.nam) that can be envisioned using NAM (Network Animator).
  1. Run the Simulation

Save the script as ring_mesh_topology.tcl and execute it using NS2:

ns ring_mesh_topology.tcl

To view the network using NAM, use:

nam ring_mesh_out.nam

Customization:

  1. Expanding the Topology:
    • We can add more nodes to extend the ring and add more mesh links among non-adjacent nodes for maximized redundancy or performance. modify the positions and connections consequently.
  2. Traffic Flows:
    • We can add additional traffic flows among diverse nodes in the topology. For instance, we can configure traffic among nodes that are directly associated in the ring or through the mesh links.
  3. Link Parameters:
    • We can adjust the bandwidth and latency of the links to mimic diverse network conditions. For instance, some links may have higher delay or lower bandwidth.

The above are the elaborated procedures that will help you to understand the basic concepts to implement the ring mesh hybrid topology that was executed using ns2 tool. If you need more information regarding the ring mesh topology we will offered it.

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