How to Implement Network Disaster Recovery in NS2

To implement the Network Disaster Recovery in NS2, we need to simulate the capability of a network to recuperate from failures involves node crashes, link failures or natural disasters which interrupts the network communication. In this case, the network must be able to redirect traffic, restore lost services and make sure fewer downtimes.

Due to NS2 can’t assist high-level disaster recovery functionalities. We have to simulate characteristics of network disaster recovery by:

  1. Launching network failures (node/link failures).
  2. Redirecting traffic or triggering backup links/nodes.
  3. Logging and evaluating recovery performance.

Here’s a guide on how to implement Network Disaster Recovery in NS2:

Step-by-Step Implementation:

  1. Set Up NS2

Make certain that NS2 is installed on your system. If it’s not installed, use:

sudo apt-get install ns2

  1. Define the Network Topology

We’ll state a network with several nodes and links. When a failure happens (mimicking a disaster), traffic will be redirected using backup paths or alternate nodes.

set ns [new Simulator]

set tracefile [open disaster_recovery.tr w]

$ns trace-all $tracefile

# Create nodes for the network

set node1 [$ns node]     ;# User node

set node2 [$ns node]     ;# Intermediate node

set node3 [$ns node]     ;# Main server

set backup_node [$ns node] ;# Backup server node

# Create links between the nodes

$ns duplex-link $node1 $node2 1Mb 10ms DropTail  ;# User to intermediate node

$ns duplex-link $node2 $node3 1Mb 10ms DropTail  ;# Intermediate node to main server

$ns duplex-link $node2 $backup_node 1Mb 10ms DropTail  ;# Intermediate node to backup server (recovery path)

  1. Simulate Normal Traffic

We replicate normal traffic amongst the user (node1) and the main server (node3). This indicates the regular operation of the network before any disaster or failure.

# Set up UDP agents for normal traffic

set udp_sender [new Agent/UDP]

set udp_receiver [new Agent/Null]

$ns attach-agent $node1 $udp_sender

$ns attach-agent $node3 $udp_receiver

$ns connect $udp_sender $udp_receiver

# Create CBR traffic generator to simulate normal traffic

set cbr_sender [new Application/Traffic/CBR]

$cbr_sender set packetSize_ 512

$cbr_sender set rate_ 1Mb

$cbr_sender attach-agent $udp_sender

# Start normal traffic at 1.0 seconds

$ns at 1.0 “$cbr_sender start”

  1. Simulate Network Failure (Disaster Event)

Imitate a disaster causing a link failure or node crash at a certain time. This interrupts the normal traffic flow.

# Simulate link failure between the intermediate node (node2) and the main server (node3)

$ns at 5.0 “$ns rtmodel-at 5.0 down $node2 $node3”

This simulates a disaster event where the main link amongst node2 and node3 fails at 5 seconds.

  1. Simulate Disaster Recovery (Rerouting Traffic)

After the failure, we redirect traffic over the backup path. In this case, traffic is redirected to the backup server (backup_node), making sure continuity of service.

(A) Activate Backup Path

We mimic rerouting traffic to the backup server by linking the user to the backup server via the intermediate node.

# Set up new UDP agents to reroute traffic to the backup server

set udp_backup_receiver [new Agent/Null]

$ns attach-agent $backup_node $udp_backup_receiver

$ns connect $udp_sender $udp_backup_receiver

# Reroute traffic to the backup server at 6.0 seconds (after the disaster)

$ns at 6.0 “$cbr_sender stop”

$ns at 6.0 “$cbr_sender attach-agent $udp_sender”

$ns at 6.0 “$cbr_sender start”

  1. Log Disaster Recovery Events

Log the failure and recovery events to find the disaster recovery process in the network.

# Function to log events related to failure and recovery

proc log_event {time event description} {

puts “$time: $event – $description”

}

# Log the link failure event

$ns at 5.0 “log_event 5.0 ‘Link Failure’ ‘Link between node2 and node3 failed (disaster)'”

# Log the recovery event (rerouting traffic)

$ns at 6.0 “log_event 6.0 ‘Traffic Rerouted’ ‘Traffic rerouted to backup server (node4)'”

  1. Run the Simulation

Once the script is ready, execute the simulation using NS2:

ns your_script.tcl

  1. Analyze the Results

After running the simulation, Confirm the trace file (disaster_recovery.tr) and console output to verify:

  • Normal traffic was successfully transferred amongst the user and the main server.
  • A disaster (link failure) happened at the particular time, interfering traffic flow.
  • Traffic was successfully rerouted to the backup server, permitting the network to recover from the disaster.

You can also use NAM (Network Animator) to visualize the network failure and recovery process.

  1. Extend the Simulation

You can extend this simulation by:

  • Adding more complex recovery mechanisms: Execute multi-path routing, automatic failover, or hot standby servers to replicate more advanced recovery strategies.
  • Introducing network-level redundancies: Make certain that the network can manage numerous failures by attaching redundant links, backup routers, or load balancers.
  • Simulating more failure scenarios: Examine the network’s flexibility by simulating several failures, node crashes, or even partial network partitions.
  • Measuring recovery time: Log the time taken for traffic to be restored and analyze the effectiveness of various recovery techniques.

With the help of this demonstration process, we have provided the useful insights regarding how to implement the network disaster recovery using ns2 and how to extend the simulation to optimize the network performance and to prevent from network failures. Keep connected with our development team for top-notch guidance on implementing Network Disaster Recovery in NS2. We’re here to provide you with the best research ideas!