To simulate an Extended Bus Topology using NS2 (Network Simulator 2), we have thoroughly understand the series of steps, which includes making a bus topology in which several nodes are associated to a general communication medium (bus) with the possibility of prolonging the topology by inserting additional segments or nodes within a hierarchical manner. In this topology, every node distributes a single communication channel, and the lengthy portion refers to including more sub-segments or repeaters to prolong the network.
Steps to Simulate Extended Bus Topology Projects in NS2
Step 1: Understand the Extended Bus Topology
In an Extended Bus Topology:
- Bus Topology: Numerous nodes are attached to a single communication medium, in which data is transmitted to all devices, however only the intended recipient processes the message.
- Extended Bus Topology: More nodes are associated to the bus through more segments, hubs, or repeaters to expand the network’s reach and capacity.
Step 2: Design the Network
We will replicate an Extended Bus Topology in which:
- Several nodes are associated to a general bus.
- More nodes are attached via a second bus segment (extended bus) through a repeater or switch.
Step 3: Create an NS2 TCL Script for Simulating the Extended Bus Topology
Following is an NS2 TCL script, which replicates an Extended Bus Topology with numerous nodes are connected to a general bus and more nodes are attached through a second bus segment.
Example: Extended Bus Topology Simulation in NS2
# Create a new NS2 simulator object
set ns [new Simulator]
# Create nodes for the first bus segment (original bus)
set bus1_node1 [$ns node] ;# Node 1 in Bus 1
set bus1_node2 [$ns node] ;# Node 2 in Bus 1
set bus1_node3 [$ns node] ;# Node 3 in Bus 1
# Create nodes for the second bus segment (extended bus)
set bus2_node1 [$ns node] ;# Node 1 in Bus 2 (extended bus)
set bus2_node2 [$ns node] ;# Node 2 in Bus 2 (extended bus)
set bus2_node3 [$ns node] ;# Node 3 in Bus 2 (extended bus)
# Create a repeater (or a switch) that connects the two bus segments
set repeater [$ns node]
# Connect nodes in the first bus segment
$ns duplex-link $bus1_node1 $bus1_node2 10Mb 5ms DropTail
$ns duplex-link $bus1_node2 $bus1_node3 10Mb 5ms DropTail
# Connect nodes in the second bus segment (extended bus)
$ns duplex-link $bus2_node1 $bus2_node2 10Mb 5ms DropTail
$ns duplex-link $bus2_node2 $bus2_node3 10Mb 5ms DropTail
# Connect the repeater to the first bus and second bus
$ns duplex-link $bus1_node3 $repeater 10Mb 5ms DropTail
$ns duplex-link $repeater $bus2_node1 10Mb 5ms DropTail
# Attach UDP agents to the end devices for communication
set udp1 [new Agent/UDP]
set udp2 [new Agent/UDP]
$ns attach-agent $bus1_node1 $udp1
$ns attach-agent $bus2_node3 $udp2
# Attach Null agents to act as sinks at the opposite end devices
set null1 [new Agent/Null]
set null2 [new Agent/Null]
$ns attach-agent $bus2_node3 $null1
$ns attach-agent $bus1_node1 $null2
# Connect the UDP agents to their respective sinks
$ns connect $udp1 $null1
$ns connect $udp2 $null2
# Create CBR traffic from Bus 1 Node 1 to Bus 2 Node 3 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 “extended_bus_topology.tr” w]
$ns trace-all $tracefile
set namfile [open “extended_bus_topology.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 extended_bus_topology.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:
- Three nodes are associated in a bus topology for both the initial bus segment (bus1_node1, bus1_node2, bus1_node3) and the prolonged bus (bus2_node1, bus2_node2, bus2_node3).
- A repeater (or switch) is utilized to connect the two bus segments that forming the extended bus topology.
- The duplex links are set up with a bandwidth of 10Mb and a delay of 5ms to replicate normal network communication within a bus topology.
- Communication Setup:
- UDP agents are connected to the nodes bus1_node1 and bus2_node3 to replicate the communication amongst the two bus segments.
- Constant Bit Rate (CBR) traffic is made among these nodes to replicate continuous data transfer between the original bus and the extended bus.
- Tracing and Visualization:
- A trace file (extended_bus_topology.tr) is made to record every network events, like packet transmissions, receptions, and drops.
- For envisioning the network topology and traffic flows, NAM file (extended_bus_topology.nam) is generated.
Step 5: Run the Simulation
- We can save the script as extended_bus_topology.tcl.
- Execute the script in NS2:
ns extended_bus_topology.tcl
It will generate two files:
- extended_bus_topology.tr: A trace files, which records the packet-level information.
- extended_bus_topology.nam: A NAM file for envisioning the network in NAM.
Step 6: Visualize the Simulation Using NAM
To envision the Extended Bus Topology within NAM:
nam extended_bus_topology.nam
In NAM, we will observe:
- Two bus segments with nodes are associated linearly.
- A repeater or switch attaching the two bus segments and that forming the extended bus.
- Packet transmissions among the nodes within the initial and second bus segments.
Step 7: Analyze the Trace File
The trace file (extended_bus_topology.tr) records every network events, like:
- Packet transmissions and receptions among the nodes.
- Packet drops or delays are triggered by network congestion or link conditions.
We can utilize the tools such as AWK, Python, or custom scripts to examine the trace file and extract crucial parameters like:
- Packet delivery ratio (PDR).
- End-to-end delay among the nodes in diverse bus segments.
- Network throughput over the repeater.
Step 8: Enhance the Simulation
Following is a few ways to expand or improve the simulation:
- Add More Bus Segments: Prolong the topology by inserting additional bus segments are associated via more repeaters or switches.
- Simulate Link Failures: Launch link failures among the nodes or the repeater to monitor how the network performs under failure conditions.
- Dynamic Traffic: Insert diverse kinds of traffic (e.g., FTP, HTTP) among the nodes to replicate additional realistic network behavior.
- Performance Metrics: Investigate the performance parameters like latency, throughput, and packet loss under diverse traffic loads or failure situations.
In this manual, we had presented the brief approach to design the network and how to simulate and examine the Extended Bus Topology projects in the NS2 environment. If needed, we can be offered more information on this topic. phdprime.com offer unparalleled guidance through our premier tools and resources, ensuring you receive the utmost support. Connect with us to explore the extensive advantages of our Extended Bus Topology Projects utilizing NS2 research simulations, meticulously customized to meet your specific requirements. Our expertise encompasses a multitude of node-related projects, and you can confidently depend on phdprime.com for your endeavors.
