How to Start Tree Topology Projects Using NS2
To start simulating a Tree Topology utilising NS2 (Network Simulator 2), this topology encompasses to organise the nodes within a hierarchical structure in which data flows from a root node to leaf nodes, or vice versa. It is generally utilised in networks such as Ethernet or hierarchical routing systems.
Following is a series of simulation steps to get started with Tree Topology project in NS2:
Steps to Start Tree Topology in NS2
- Understand Tree Topology
- Structure:
- Nodes are hierarchically organized including a root node, branches, and leaf nodes.
- Data flows from root node to leaves node which is called as downstream or flows from leaves node to root node that is upstream.
- Applications:
- This topology is appropriate for hierarchical routing and data aggregation.
- Generally utilised in multicast networks and IoT applications.
- Set Up NS2
- Install NS2:
sudo apt-get install ns2
- Verify Installation: Confirm set up including a simple example simulation script:
ns example.tcl
- Define Tree Topology
- Create a tree topology with nodes and hierarchically organize them.
- Launch connections among the parent and child nodes.
- TCL Script for Tree Topology
Here’s an instance of TCL script for replicating a Tree Topology:
TCL Script Example
# Initialize NS2 Simulator
set ns [new Simulator]
set tracefile [open tree_topology.tr w]
$ns trace-all $tracefile
# Define nodes (Example: 1 root, 2 intermediate, 4 leaf nodes)
set root [$ns node]
set intermediate1 [$ns node]
set intermediate2 [$ns node]
set leaf1 [$ns node]
set leaf2 [$ns node]
set leaf3 [$ns node]
set leaf4 [$ns node]
# Create tree links
$ns duplex-link $root $intermediate1 1Mb 10ms DropTail
$ns duplex-link $root $intermediate2 1Mb 10ms DropTail
$ns duplex-link $intermediate1 $leaf1 1Mb 10ms DropTail
$ns duplex-link $intermediate1 $leaf2 1Mb 10ms DropTail
$ns duplex-link $intermediate2 $leaf3 1Mb 10ms DropTail
$ns duplex-link $intermediate2 $leaf4 1Mb 10ms DropTail
# Attach agents for traffic
# Traffic from root to leaf1
set udp0 [new Agent/UDP]
$ns attach-agent $root $udp0
set null0 [new Agent/Null]
$ns attach-agent $leaf1 $null0
$ns connect $udp0 $null0
# Traffic from root to leaf3
set udp1 [new Agent/UDP]
$ns attach-agent $root $udp1
set null1 [new Agent/Null]
$ns attach-agent $leaf3 $null1
$ns connect $udp1 $null1
# Add traffic generators
set cbr0 [new Application/Traffic/CBR]
$cbr0 set packetSize_ 512
$cbr0 set interval_ 0.2
$cbr0 attach-agent $udp0
set cbr1 [new Application/Traffic/CBR]
$cbr1 set packetSize_ 512
$cbr1 set interval_ 0.3
$cbr1 attach-agent $udp1
# Start traffic
$ns at 1.0 “$cbr0 start”
$ns at 1.5 “$cbr1 start”
# End simulation
$ns at 5.0 “finish”
proc finish {} {
global ns tracefile
$ns flush-trace
close $tracefile
exit 0
}
$ns run
- Key Features to Simulate
- Traffic Flow: Make sure that data flows properly through the hierarchical structure.
- Performance Metrics:
- Throughput: Estimate the data distribution to leaf nodes.
- Delay: Examine latency from root node to leaves.
- Fault Tolerance: Replicate the link or node failures.
- Analyze Trace File
- Make use of the trace file as tree_topology.tr for detailed analysis.
- We can obtain certain performance parameters such as:
- Throughput:
grep “tcp” tree_topology.tr > throughput.log
-
- Dropped Packets:
grep “drop” tree_topology.tr > dropped_packets.log
- Visualize Results
To envision the outcomes, we need to leverage tools like Gnuplot or another plotting tool:
- Throughput Graph:
set title “Tree Topology Throughput”
plot “throughput.log” using 1:2 with lines title “Throughput”
- Latency Graph: Envision packet delays through the branches.
- Extend the Simulation
- Multicast Communication
- Replicate the multicast interaction from root node to numerous leaf nodes.
- Execute multicasting mechanisms such as Protocol Independent Multicast (PIM).
- Simulate Failures
- Mimic a link or node failure and redirect traffic for sustaining the interaction.
- QoS in Tree Topology
- Launch delay-sensitive or bandwidth-sensitive traffic, monitoring the performance in diverse scenarios within tree topology.
- Custom Protocols
- Execute the custom protocols for routing, aggregation, or fault tolerance.
- Modify NS2 Core for Advanced Features
For more advanced aspects, we can:
- Node Failure Simulation: Fine-tune the recv() approach in a custom agent for replicating the node or link failures.
void TreeNode::recv(Packet* p) {
if (isFailure()) {
drop(p);
} else {
forward(p);
}
}
- Dynamic Tree Structures:
- Actively replicate the growing or shrinking trees.
Tools and Resources
- Wireshark: Examine the traffic models from the trace file using Wireshark tools.
- Gnuplot: Envision performance parameters such as throughput, latency, and other metrics with the support of Gnuplot.
- NS2 Documentation: We can refer the NS2 documentation for custom agents and topology improvements.
Enhancements
- Add IoT Applications: Replicate the tree-based interaction for resource-constrained IoT networks.
- Incorporate Fault Recovery: Focus on how tree topology manages the link or node failures.
- Compare Tree Topology vs Other Topologies: Examine the performance variations of tree topology with ring, star, or mesh topologies.
By leveraging these procedures, we had done the simulation process successfully for Tree Topology projects in NS2 simulation tool and it also deliver the comprehensive procedures to simulate the process, coding snippets and deliver the future enhancement. If you need more details we will offered it.