To simulate Hybrid Topology in ns2has need to integrate multiple kinds of topologies such as star, ring, bus, tree, and mesh into a single network. To replicates such a topology in NS2 has includes generating nodes and associates them using numerous topologies, integrates them into one cohesive network.
Here’s how you can simulate a Hybrid Topology project in NS2:
Steps to Simulate Hybrid Topology Projects in NS2
- Set up NS2 Environment:
Make sure that NS2 is installed and appropriately configured. We will compose a TCL script to replicate the hybrid topology.
- Understanding Hybrid Topology:
- A Hybrid Topology integrates the strengths of different topologies. For example, we have a star topology associated to a bus, with one part of the network in a ring configuration.
- Hybrid topologies are usually utilized in real-world networks because they integrate scalability, fault tolerance, and ease of maintenance.
- Create a TCL Script for Hybrid Topology:
Let’s generate a basic Hybrid Topology that associations star and ring topologies into a single network.
Example: Hybrid of Star and Ring Topologies
# Create a new simulator instance
set ns [new Simulator]
# Open a NAM file for visualization
set nf [open out.nam w]
$ns namtrace-all $nf
# Create nodes for Star Topology (Center node connected to other nodes)
set star_center [$ns node]
set star_n1 [$ns node]
set star_n2 [$ns node]
set star_n3 [$ns node]
# Create nodes for Ring Topology
set ring_n1 [$ns node]
set ring_n2 [$ns node]
set ring_n3 [$ns node]
set ring_n4 [$ns node]
# Create a Bus connecting the Star and Ring (hybrid connection)
set bus_n1 [$ns node]
set bus_n2 [$ns node]
# Create links for Star Topology (Star center node connected to star nodes)
$ns duplex-link $star_center $star_n1 10Mb 10ms DropTail
$ns duplex-link $star_center $star_n2 10Mb 10ms DropTail
$ns duplex-link $star_center $star_n3 10Mb 10ms DropTail
# Create links for Ring Topology
$ns duplex-link $ring_n1 $ring_n2 10Mb 10ms DropTail
$ns duplex-link $ring_n2 $ring_n3 10Mb 10ms DropTail
$ns duplex-link $ring_n3 $ring_n4 10Mb 10ms DropTail
$ns duplex-link $ring_n4 $ring_n1 10Mb 10ms DropTail
# Create Bus topology links connecting Star and Ring networks
$ns duplex-link $star_center $bus_n1 10Mb 10ms DropTail
$ns duplex-link $bus_n1 $bus_n2 10Mb 10ms DropTail
$ns duplex-link $bus_n2 $ring_n1 10Mb 10ms DropTail
# Attach UDP agents to generate traffic
set udp_star [new Agent/UDP]
$ns attach-agent $star_n1 $udp_star
set udp_ring [new Agent/UDP]
$ns attach-agent $ring_n4 $udp_ring
# Attach Null agents to receive the traffic
set null_star [new Agent/Null]
$ns attach-agent $ring_n2 $null_star
set null_ring [new Agent/Null]
$ns attach-agent $star_n3 $null_ring
# Connect the agents
$ns connect $udp_star $null_star
$ns connect $udp_ring $null_ring
# Create CBR traffic on both sides (Star and Ring nodes)
set cbr_star [new Application/Traffic/CBR]
$cbr_star attach-agent $udp_star
$cbr_star set packetSize_ 512
$cbr_star set rate_ 100Kb
set cbr_ring [new Application/Traffic/CBR]
$cbr_ring attach-agent $udp_ring
$cbr_ring set packetSize_ 512
$cbr_ring set rate_ 100Kb
# Schedule the traffic to start and stop
$ns at 1.0 “$cbr_star start”
$ns at 1.5 “$cbr_ring start”
$ns at 5.0 “$cbr_star stop”
$ns at 5.5 “$cbr_ring stop”
# Define when to finish the simulation
$ns at 7.0 “finish”
proc finish {} {
global ns nf
$ns flush-trace
close $nf
exec nam out.nam &
exit 0
}
# Start the simulation
$ns run
- Explanation of the Code:
- Star Topology: Nodes star_center, star_n1, star_n2, and star_n3 are associated in a star formation with the central node star_center.
- Ring Topology: Nodes ring_n1, ring_n2, ring_n3, and ring_n4 form a ring in which each node is associated to two other nodes in a circular manner.
- Bus Topology: A bus associates the star and ring networks via the nodes bus_n1 and bus_n2, with links between star_center, bus_n1, bus_n2, and ring_n1.
- Traffic: Two sets of UDP agents and CBR traffic are set up: one from the star network to the ring network and one from the ring network to the star network. The traffic flows among nodes in the star and ring topologies across the bus.
- Run the Simulation:
- Save the script as hybrid_topology.tcl.
- Open a terminal and navigate to the folder encompassing the script.
- Execute the simulation using:
ns hybrid_topology.tcl
- The simulation will create an out.nam file that can be envisioned using Network Animator (NAM).
- Enhancing the Hybrid Topology:
- Add More Nodes: We can incorporate more nodes and links to the star, ring, and bus sections to generate a larger hybrid topology.
- Advanced Traffic Patterns: we can establish different traffic types, like TCP, FTP, or different data rates and packet sizes.
- Simulation of Failures: we can replicate failures by disabling links or nodes and monitor on how the hybrid topology adjust or reroutes traffic.
- Customization:
- Adding Mesh Topology: we can expand the hybrid topology by incorporate a mesh network to associate multiple nodes together.
- Implement Hierarchical Networks: By integrating tree topology with the hybrid structure, we can generate hierarchical networks, in which the tree hierarchy can connect to a star, ring, or mesh network.
Overall, we had clearly obtainable the detailed description to perform the Hybrid Topology projects with sample code snippets were given above that were evaluated in ns2 implementation tool. We also further provide the detailed information that related to Hybrid Topology.
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