To simulate a Bus-Star Hybrid Topology within Network Simulator 2 (NS2) that needs to include aggregating two kinds of topologies, one is Bus another one is Star topology into a single hybrid network. This configuration could be utilized within real-world scenarios in which diverse sub-networks are associated by using a bus topology, and each sub-network has their nodes are organized in a star configuration. Here’s a comprehensive instructions on how to simulate Bus-Star Hybrid Topology projects with samples using NS2:
Steps to Simulate Bus Star Hybrid Topology Projects in NS2
In the Bus-Star Hybrid Topology:
- Bus Topology: The nodes or groups of nodes are attached within a linear fashion that all distributing a general communication medium.
- Star Topology: Each sub-network is organized within a star topology in which a central node (typically a switch, router, or hub) associates to other nodes (hosts).
Step 1: Understand the Hybrid Topology
In a Bus-Star Hybrid Topology:
- The Bus Topology associates numerous star topologies in a linear or shared medium.
- Each star topology contains a central node (like a router or switch), which attaches to multiple end devices (hosts).
- The bus serves as a backbone, which links several star-shaped sub-networks.
Step 2: Design the Network
We will replicate a Bus-Star Hybrid Topology where:
- Two or more star topologies are associated through a bus topology.
- Each star topology includes a central switch and numerous end devices.
- The bus associates these central switches that permitting traffic among the diverse star networks.
Step 3: Create an NS2 TCL Script for Simulating the Bus-Star Hybrid Topology
Following is an NS2 TCL script, which mimics a Bus-Star Hybrid Topology including two star topologies are connected through a bus.
Example: Bus-Star Hybrid Topology Simulation in NS2
# Create a new NS2 simulator object
set ns [new Simulator]
# Create nodes for two star topologies and the bus backbone
set star1_center [$ns node] ;# Central node of Star 1
set star2_center [$ns node] ;# Central node of Star 2
set bus_node1 [$ns node] ;# First bus node (connected to Star 1)
set bus_node2 [$ns node] ;# Second bus node (connected to Star 2)
# Create end devices for Star 1
set star1_node1 [$ns node] ;# End device 1 in Star 1
set star1_node2 [$ns node] ;# End device 2 in Star 1
set star1_node3 [$ns node] ;# End device 3 in Star 1
# Create end devices for Star 2
set star2_node1 [$ns node] ;# End device 1 in Star 2
set star2_node2 [$ns node] ;# End device 2 in Star 2
set star2_node3 [$ns node] ;# End device 3 in Star 2
# Create the bus links between the bus nodes (representing the backbone)
$ns duplex-link $bus_node1 $bus_node2 10Mb 20ms DropTail
# Connect the star central nodes to the bus nodes
$ns duplex-link $star1_center $bus_node1 10Mb 10ms DropTail
$ns duplex-link $star2_center $bus_node2 10Mb 10ms DropTail
# Create links for Star 1 (central node connecting to end devices)
$ns duplex-link $star1_center $star1_node1 1Mb 5ms DropTail
$ns duplex-link $star1_center $star1_node2 1Mb 5ms DropTail
$ns duplex-link $star1_center $star1_node3 1Mb 5ms DropTail
# Create links for Star 2 (central node connecting to end devices)
$ns duplex-link $star2_center $star2_node1 1Mb 5ms DropTail
$ns duplex-link $star2_center $star2_node2 1Mb 5ms DropTail
$ns duplex-link $star2_center $star2_node3 1Mb 5ms DropTail
# Attach UDP agents to the end devices of both star topologies
set udp1 [new Agent/UDP]
set udp2 [new Agent/UDP]
$ns attach-agent $star1_node1 $udp1
$ns attach-agent $star2_node1 $udp2
# Attach a Null agent to act as a sink at the opposite star topology nodes
set null1 [new Agent/Null]
set null2 [new Agent/Null]
$ns attach-agent $star2_node1 $null1
$ns attach-agent $star1_node1 $null2
# Connect the UDP agents to their respective sinks
$ns connect $udp1 $null1
$ns connect $udp2 $null2
# Generate CBR (Constant Bit Rate) traffic from Star 1 to Star 2 and vice versa
set cbr1 [new Application/Traffic/CBR]
$cbr1 set packetSize_ 512
$cbr1 set interval_ 0.1
$cbr1 attach-agent $udp1
set cbr2 [new Application/Traffic/CBR]
$cbr2 set packetSize_ 512
$cbr2 set interval_ 0.1
$cbr2 attach-agent $udp2
# Start the traffic flows
$ns at 1.0 “$cbr1 start”
$ns at 1.5 “$cbr2 start”
# Create trace and nam files for recording the simulation events
set tracefile [open “bus_star_hybrid.tr” w]
$ns trace-all $tracefile
set namfile [open “bus_star_hybrid.nam” w]
$ns namtrace-all $namfile
# Define the finish procedure to close files and start NAM
proc finish {} {
global ns tracefile namfile
$ns flush-trace
close $tracefile
close $namfile
exec nam bus_star_hybrid.nam &
exit 0
}
# Finish the simulation after 10 seconds
$ns at 10.0 “finish”
# Run the simulation
$ns run
Step 4: Explanation of the Script
- Network Setup:
- Two star topologies are made. Each star topology encompasses a central node (star1_center and star2_center) is related to three end devices.
- A bus topology attaches the two star topologies. The bus nodes (bus_node1 and bus_node2) are working as the connection points amongst the central nodes of each star topology.
- The bus offers a backbone for communication among the two star topologies.
- Communication Setup:
- UDP agents are connected to the end devices within each star topology, which allowing the traffic flow among devices in diverse stars.
- Constant Bit Rate (CBR) traffic is made amongst the nodes in Star 1 and Star 2 utilizing the bus backbone.
- Link Characteristics:
- The links among the bus nodes and between the central star nodes and their end devices are set up with distinct bandwidths and delays to replicate the real-world situations.
- Tracing and Visualization:
- A trace file (bus_star_hybrid.tr) is made to record the network events, like packet transmissions, receptions, and drops.
- For envisioning the network topology and traffic flows, NAM file (bus_star_hybrid.nam) is created.
Step 5: Run the Simulation
- We can save the script as bus_star_hybrid.tcl.
- Execute the script in NS2:
ns bus_star_hybrid.tcl
It will generate two files:
- bus_star_hybrid.tr: A trace files, which records the packet-level information.
- bus_star_hybrid.nam: A NAM file for envisioning the network within NAM.
Step 6: Visualize the Simulation Using NAM
To envision the Bus-Star Hybrid Topology in NAM:
nam bus_star_hybrid.nam
In NAM, we will observe:
- The two star topologies, that each with a central node and its associated the end devices.
- The bus backbone attaching the central nodes of the two star topologies.
- Packet transmissions amongst the nodes as traffic flows between Star 1 and Star 2.
Step 7: Analyze the Trace File
The trace file (bus_star_hybrid.tr) records every network events, like:
- Packet transmissions and receptions amongst the nodes.
- Packet drops or delays are triggered by congestion or network conditions.
We can utilize the tools such as AWK, Python, or custom scripts to examine the trace file and extract crucial performance parameters like:
- Packet delivery ratio (PDR).
- End-to-end delay among the nodes in diverse star topologies.
- Network throughput over the bus backbone.
Step 8: Enhance the Simulation
Below is a few ways to prolong or improve the simulation:
- Add More Star Topologies: Prolong the bus to attach additional star topologies that replicating a larger hybrid network.
- Simulate Link Failures: Launch the link or node failures and monitor how the network performs when a few links are down.
- Introduce Dynamic Traffic: Insert diverse kinds of traffic such as FTP, HTTP among the nodes to model further realistic network scenarios.
- Measure Performance Metrics: Examine the performance parameters like latency, throughput, and packet loss under distinct network loads or failure scenarios.
We successfully explicated the essential information and detailed example with its explanation on how to simulate the Bus Star Hybrid Topology projects and how to visualize and analyse their performance with the support of NS2 tool. We will also be provided any other details related to this subject, if needed. We help you in every way possible with our top tools and resources. Contact us for customized research simulation benefits for Bus Star Hybrid Topology Projects Using NS2. For the best star configuration in your work, trust phdprime.com.
