How to Implement Dual Ring Topology in NS2

To implement the Dual Ring Topology in Network Simulator 2 (ns2) which is a variant of network topology that has two rings nodes which are linked usually in alternate directions. It offers redundancy and fault tolerance, if one ring fails, you can use other ring for communication. These topologies are frequently used in high-consistency environments like Fiber Distributed Data Interface (FDDI) and resilient packet ring (RPR) networks.

You can simulate a Dual Ring Topology by generating two pair of duplex links that link nodes in both clockwise and counterclockwise directions in the ns2.

In the following below, we delivered the information regarding the implementation of dual ring topology in ns2:

Steps to Implement Dual Ring Topology in NS2:

  1. Set Up the Nodes:
    • Configure the nodes that will form the rings.
  2. Connect Nodes in Both Clockwise and Counterclockwise Rings:
    • Link the nodes in a circular manner for the clockwise ring by using duplex links.
    • Generate extra duplex links in the reverse direction (counterclockwise) to form the second ring.
  3. Simulate Traffic Flow:
    • Produce traffic amongst nodes that can move on either ring.

Example of Dual Ring Topology Implementation in NS2:

Below is an example NS2 script that replicates a Dual Ring Topology with 4 nodes linked in both clockwise and counterclockwise directions.

# Create a new simulator

set ns [new Simulator]

# Open trace file for output

set tracefile [open out.tr w]

$ns trace-all $tracefile

# Define nodes in the rings (4 nodes for simplicity)

set n0 [$ns node]

set n1 [$ns node]

set n2 [$ns node]

set n3 [$ns node]

# Create duplex links in the clockwise direction

$ns duplex-link $n0 $n1 10Mb 5ms DropTail

$ns duplex-link $n1 $n2 10Mb 5ms DropTail

$ns duplex-link $n2 $n3 10Mb 5ms DropTail

$ns duplex-link $n3 $n0 10Mb 5ms DropTail  ;# Complete the clockwise ring

# Create duplex links in the counterclockwise direction

$ns duplex-link $n1 $n0 10Mb 5ms DropTail

$ns duplex-link $n2 $n1 10Mb 5ms DropTail

$ns duplex-link $n3 $n2 10Mb 5ms DropTail

$ns duplex-link $n0 $n3 10Mb 5ms DropTail  ;# Complete the counterclockwise ring

# Define TCP agents for communication

# Traffic from n0 to n2 (can travel on either ring)

set tcp0 [new Agent/TCP]

set sink0 [new Agent/TCPSink]

$ns attach-agent $n0 $tcp0

$ns attach-agent $n2 $sink0

$ns connect $tcp0 $sink0

# Simulate FTP traffic from n0 to n2

set ftp0 [new Application/FTP]

$ftp0 attach-agent $tcp0

$ns at 1.0 “$ftp0 start”

$ns at 3.0 “$ftp0 stop”

# Traffic from n3 to n1 (using opposite ring)

set tcp1 [new Agent/TCP]

set sink1 [new Agent/TCPSink]

$ns attach-agent $n3 $tcp1

$ns attach-agent $n1 $sink1

$ns connect $tcp1 $sink1

# Simulate FTP traffic from n3 to n1

set ftp1 [new Application/FTP]

$ftp1 attach-agent $tcp1

$ns at 4.0 “$ftp1 start”

$ns at 6.0 “$ftp1 stop”

# End the simulation after 10 seconds

$ns at 10.0 “finish”

proc finish {} {

global ns tracefile

$ns flush-trace

close $tracefile

exit 0

}

# Run the simulation

$ns run

Explanation of the Script:

  1. Nodes:
    • n0, n1, n2, and n3 are the nodes in the dual ring topology.
  2. Clockwise Ring:
    • Duplex links are developed amongst the nodes in a circular manner (n0 -> n1 -> n2 -> n3 -> n0). These links indicate the clockwise ring.
  3. Counterclockwise Ring:
    • Another set of duplex links is created in the opposite direction (n1 -> n0, n2 -> n1, n3 -> n2, and n0 -> n3), making the counterclockwise ring. This forms the redundancy typical in a dual ring topology.
  4. Traffic Simulation:
    • Use TCP agents to simulate communication amongst nodes.
    • Use FTP (File Transfer Protocol) to produce traffic amongst nodes. For instance, traffic flows from n0 to n2 (which could use either the clockwise or counterclockwise ring), and from n3 to n1 (likely using the counterclockwise ring).
  5. Simulation Duration:
    • The simulation executes for 10 seconds, with traffic flowing amidst nodes through the dual ring network.

Post-Simulation Analysis:

  1. Trace File Analysis:
    • The trace file (out.tr) will contain details about packet transmission, delivery, delay, and throughput. Compute how traffic flows over the dual rings by analyze this file.
  2. NAM Visualization:
    • Use NAM (Network Animator) is used to visualize the dual ring topology. This will show the two rings and the paths taken by traffic as it flows amongst nodes.
  3. Performance Metrics:
    • Calculate network performance metrics includes delay, throughput, and packet loss to assess how the dual ring topology functions.

Enhancing the Simulation:

  1. Adding More Nodes:
    • Simulate a larger dual ring network by including more nodes. Make sure that all nodes are connected in both directions (clockwise and counterclockwise).
  2. Simulating Link or Node Failures:
    • Simulate link or node failures to observe how the network redirects traffic using the redundant ring.
  3. Dynamic Traffic Routing:
    • Execute a more dynamic traffic routing functionalities to select the best ring according to the network conditions (such as shortest path or least blockage).
  4. Changing Traffic Types:
    • Assess how the dual ring topology manages numerous traffic patterns by replacing TCP with UDP or simulating different kinds of traffic (like CBR).
  5. Varying Link Parameters:
    • Experiment with various link parameters like bandwidth, delay, and queue types (such as DropTail, RED) to learn how the network performance differs in various conditions.

In this procedure, we can completely understand how to set up and implement the Dual ring topology and how to connect the ring in both clockwise and anticlockwise in the ns2 simulation environment. For further requirements, we will guide you through another simulation process.

For optimal support regarding Dual Ring Topology implementation in NS2, you may contact ns2project.com for expert guidance. We offer comprehensive assistance on various topics. Our focus includes Fiber Distributed Data Interface (FDDI) and resilient packet ring (RPR) networks.