How to Start a Path Vector Routing Project Using NS2

To stimulate the Path Vector Routing is a kind of routing protocol in which every router handles the data about the comprehensive path to reach the destination. This is same to Distance Vector Routing nevertheless in its place for just the “distance” or hop count, every node has commercial the actual path such as the sequence of routers we reach a destination.

The Path Vector Routing is used in the protocols such as BGP (Border Gateway Protocol) in real-world environment for inter-domain routing, in which the routers handle the full path of the destination. In NS2, we can replicate the Path Vector Routing through apply a alter method or adjust the previous protocols such as BGP for operates in your network simulation.

Steps to Start a Path Vector Routing Project in NS2

  1. Install NS2

If you have not previously installed NS2, follow the procedure for installation:

  • For Linux (Ubuntu/Debian-based):

sudo apt update

sudo apt install ns2

sudo apt install nam

  • For Windows: We may require using a virtual machine or Cygwin as NS2 is not natively help for the Windows.

Next installation, validate which operates the command for the process:

ns

  1. Understand Path Vector Routing

In Path Vector Routing, the routers have handled the data not only about the distance but also about the sequence of routers or nodes which data must pass through to reach the destination. The path is commercial, and when a node receives a routing commercial, it bring up-to-date its routing table through adding the receiving path to the advertisement.

For instance:

  • A node might commercial path such as A → B → C → D, which importance the destination can be reached by this router.
  • If a node receives an advertisement through a path A → B → C → D, it will bring up-to-date its table and prefer the minimum path.

This type of routing is beneficial for large-scale networks like the Internet, where the topology is complex, and simple metrics like hop count are insufficient.

  1. Set up the NS2 Simulation

The next procedure is describing the network topology and replicates the Path Vector Routing. We can use a previous protocol such as BGP or build a simple replication using a customized routing protocol which follows the full paths.

  1. Create the TCL Script for Path Vector Routing

Under the sample on how to replicate the simple Path Vector Routing protocol. We will replicate a simple environment in which the routers such as nodes are handle the paths and bring up-to-date their routing tables when they receive a new advertisements from neighbours.

Example TCL Script: Simulating Path Vector Routing

In this example, we’ll simulate a small network with 4 nodes (routers), where each router advertises the full path to the destination.

# Create a new simulator object

set ns [new Simulator]

# Create nodes (4 nodes in the network)

set n0 [$ns node]  ;# Router 1

set n1 [$ns node]  ;# Router 2

set n2 [$ns node]  ;# Router 3

set n3 [$ns node]  ;# Router 4 (Destination)

# Create links between nodes (with bandwidth and delay)

$ns duplex-link $n0 $n1 10Mb 10ms DropTail

$ns duplex-link $n1 $n2 10Mb 10ms DropTail

$ns duplex-link $n2 $n3 10Mb 10ms DropTail

# Define a simple Path Vector Routing protocol (for illustration purposes)

# In a real implementation, you’d likely modify or extend an existing protocol

# like BGP in NS2 to use the path vector concept.

# Path Vector Routing – Advertise paths to neighbors

proc advertise_paths {node neighbor destination path} {

global ns

# Node advertises the full path to its neighbors

puts “Node $node: Advertising path $path to $neighbor”

# Simulate receiving a path advertisement (in reality, this would be dynamic)

if {$neighbor eq $destination} {

puts “Node $node: Reached destination with path $path”

} else {

# Add neighbor to the path and propagate

set new_path “$path -> $neighbor”

advertise_paths $neighbor $destination $new_path

}

}

# Start the advertisement from node 0 to node 3

advertise_paths 0 1 3 “n0”

advertise_paths 1 2 3 “n0 -> n1”

advertise_paths 2 3 3 “n0 -> n1 -> n2”

# Define traffic flow (UDP: CBR from n0 to n3)

set udp1 [new Agent/UDP]

set sink1 [new Agent/Null]

$sink1 attach-agent $n3

$udp1 attach-agent $n0

set cbr1 [new Application/Traffic/CBR]

$cbr1 set packetSize_ 512

$cbr1 set interval_ 0.1  ;# Set rate for CBR traffic

$cbr1 attach-agent $n0

$ns connect $udp1 $sink1

# Set start and stop times for traffic

$ns at 1.0 “$cbr1 start”

$ns at 5.0 “$cbr1 stop”

# Enable trace output to monitor the packet flow and routing

$ns trace-all “path_vector_output.tr”

$ns namtrace-all “path_vector_output.nam”

# Run the simulation

$ns run

  1. Explanation of the TCL Script
  1. Nodes and Links:
    • This replication contains the four nodes are connected in a line: n0 → n1 → n2 → n3.
    • Every connection among the nodes is described through a bandwidth such as 10Mb and delay like as 10ms, using DropTail as the queue management.
  2. Path Vector Protocol:
    • A simple Path Vector Routing mechanism is made by the advertise_paths methods that replicates on how the nodes advertise their full path to the destination.
    • In a real-world environment, this would has includes the transfer a routing updates to neighbours and bring up-to-date the routing table by the full path to the destination.
  3. Traffic Flow:
    • A CBR (Constant Bit Rate) congestion flow is setting from node n0 such as source to node n3 like as destination.
    • This replicates the UDP congestion that will traverse the path determined through the path vector protocol.
  4. Trace and NAM:
    • Trace output: The trace file such as path_vector_output.tr records the details for packet movements has including routing bring up-to-date.
    • NAM animation: The NAM file like as path_vector_output.nam envisions the packet flow and routing behavior.
  1. Simulate and Analyze the Results

Next process for the replication of outcomes:

  • NAM Visualization:

nam path_vector_output.nam

This releases the NAM animation, in which we can view on how the packet flows from n0 to n3 and follow the routing paths being advertised among nodes.

  • Trace File Analysis: Used the file tools like awk or modify the characters we examine the trace file such as path_vector_output.tr and view on how routing decisions were create and that paths were advertised.

Example:

awk ‘{print $1, $2, $3, $4}’ path_vector_output.tr

This will help you follow the flow of packets and the path bring up-to-date as nodes propagate the paths.

  1. Extending the Path Vector Routing Project

We can spread this project through apply further complex features:

  1. Dynamic Path Updates: Alter the characters to dynamically bring up to date the path according to the network changes such as connection failures or congestion.
  2. Real Protocol Implementation (BGP): If we need further realistic replication, you can spread or modify he previous BGP apply in NS2 we help with the path vector routing. BGP use path vectors and is generally used in the Internet for inter-domain routing.
  3. Multiple Flows: Improve the several congestion flows from various sources and destinations; follow on how the paths evolve and how the network adjusts.
  4. Mobility: Execute the mobile nodes and replicate on how the path vectors adapt to node movements and changing topologies. This is relevant for MANETs (Mobile Ad hoc Networks).
  5. Advanced Routing Metrics: Improve the routing decisions to integrate not just hop count, nevertheless also connection quality, bandwidth, delay, or other parameter metrics in the path vector.

These projects will give you practical insights into the performance and behaviour of Path vector routing in different network scenarios using NS2. Overall, we have entirely explained projects example using the implementation and execution process that related to path vector routing which is enforced using ns2. We will deliver more projects examples in upcoming manuals.