How to Implement Anomaly based IDS in NS2

To implement an Anomaly-based Intrusion Detection System (IDS) within NS2, we can be replicated traffic monitoring and anomaly detection depends on traffic behaviour. Anomaly-based IDSs work by detecting the deviations from typical traffic patterns, like unexpected packet sizes, unusual traffic rates, or unauthorized IP addresses. The simulation environment NS2 can use to replicate these traffic patterns and identify anomalies by comparing real-time traffic versus a predefined “normal” behaviour model. Given below is a basic approach to executing an Anomaly-based IDS in NS2:

Step-by-Step Implementation:

  1. Set up NS2

Make certain that NS2 is installed on the machine. If it is not installed, we can install it using:

sudo apt-get install ns2

  1. Define the Network Topology

Initially, we require to state a network topology including a sender, receiver, and an intermediate node, which performs as the IDS. The IDS monitors the traffic among the sender and receiver, identifying any anomalies.

set ns [new Simulator]

set tracefile [open anomaly_ids.tr w]

$ns trace-all $tracefile

# Create sender, receiver, and IDS node

set sender [$ns node]

set receiver [$ns node]

set ids_node [$ns node]  ;# Intermediate node that acts as the IDS

# Create links between the nodes

$ns duplex-link $sender $ids_node 1Mb 10ms DropTail

$ns duplex-link $ids_node $receiver 1Mb 10ms DropTail

  1. Simulate Normal Traffic

Replicate the normal traffic among the sender and receiver using UDP and CBR (Constant Bit Rate) traffic generators. It will be served as baseline traffic pattern.

# Set up UDP agents for sender and receiver

set udp_sender [new Agent/UDP]

set null_receiver [new Agent/Null]

$ns attach-agent $sender $udp_sender

$ns attach-agent $receiver $null_receiver

$ns connect $udp_sender $null_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 generating normal traffic at 1.0 second

$ns at 1.0 “$cbr_sender start”

  1. Define Anomaly Detection Logic

An anomaly-based IDS performs by comparing the monitored traffic patterns to typical behaviour. In this scenario, we describe an anomaly if traffic outdoes a predefined threshold (e.g., unusual packet size or traffic rate).

(A) Detect Anomalous Traffic

We can be mimicked the IDS detecting anomalous traffic by verifying packet size or traffic rate. If the packet size or rate exceeds the described normal behaviour then the IDS activates an alert.

# Function to detect anomalies based on packet size

proc detect_anomaly {packet_size threshold node_id} {

if { $packet_size > $threshold } {

puts “IDS on Node $node_id: Anomaly detected! Packet size $packet_size exceeds threshold $threshold”

return 1  ;# Anomaly detected

} else {

return 0  ;# No anomaly

}

}

# Define the normal packet size threshold

set normal_threshold 512  ;# Normal packet size threshold

# Simulate normal traffic and anomaly detection

$ns at 2.0 “detect_anomaly 512 $normal_threshold ids_node”  ;# Normal packet size

$ns at 3.0 “detect_anomaly 1024 $normal_threshold ids_node”  ;# Anomalous packet size

  1. Simulate Traffic Anomalies

To test the IDS, we can simulate anomalous traffic patterns. For example, we can generate traffic with larger-than-normal packet sizes or different traffic rates that will be flagged by the IDS as anomalous.

(A) Simulate Anomalous Traffic (e.g., larger packets or abnormal rates)

Generate anomalous traffic to activated the IDS detection.

# Set up a new CBR generator to simulate anomalous traffic with large packet size

set cbr_anomalous [new Application/Traffic/CBR]

$cbr_anomalous set packetSize_ 1024  ;# Anomalous packet size (larger than normal)

$cbr_anomalous set rate_ 2Mb  ;# Higher rate than normal

$cbr_anomalous attach-agent $udp_sender

# Start generating anomalous traffic at 3.0 seconds

$ns at 3.0 “$cbr_anomalous start”

  1. Log Anomalies Detected by the IDS

To observe the functioning of the IDS, we record any anomalies detected by the IDS rely on deviations from the normal traffic pattern.

# Log anomalies detected by the IDS

proc log_anomaly_detection {node_id packet_size anomaly_detected} {

if { $anomaly_detected == 1 } {

puts “Anomaly Detected by IDS on Node $node_id: Packet size $packet_size”

} else {

puts “Traffic on Node $node_id is normal.”

}

}

# Log the detection events

$ns at 2.5 “log_anomaly_detection ids_node 512 0”  ;# Normal traffic

$ns at 3.5 “log_anomaly_detection ids_node 1024 1”  ;# Anomalous traffic

  1. Run the Simulation

When the script is ready then run the simulation using NS2:

ns your_script.tcl

  1. Analyse the Results

After running the simulation, verify the trace file (anomaly_ids.tr) and console the results to check:

  • Normal traffic was generated and detected without any alerts.
  • Anomalous traffic (e.g., larger packet sizes or unusual traffic rates) was identified by the IDS, and alerts were activated.

Also we can be used the NAM (Network Animator) to envision the traffic flow among the sender, IDS node, and receiver.

  1. Extend the Simulation

We can extend this simulation by:

  • Adding multiple detection criteria: Observe more traffic parameters like IP addresses, port numbers, or packet arrival rates to identify more kinds of anomalies.
  • Implementing more complex traffic patterns: Replicate the bursty or malicious traffic (e.g., DDoS attacks) and monitor how the anomaly-based IDS responds.
  • Using machine learning models: Integrate machine learning models (outside of NS2) to examine the traffic patterns and we use the outcomes to train the anomaly detection logic within NS2.
  • Simulating network attacks: Mimic various kind of network attacks, like flooding attacks, and also examine how the anomaly-based IDS responds.

As above, we thoroughly demonstrated the brief implementations procedure with example coding to execute and analyse the Anomaly based IDS within NS2 virtual environment. More informations will be offered according to your requirements.

Obtain top project ideas and expert advice on handling unexpected packet sizes, atypical traffic rates, or unauthorized IP addresses. For assistance with any type of anomaly-based Intrusion Detection System (IDS) implementation in NS2, please reach out to us, and we will ensure you receive optimal results.