Selective Repeat ARQ Simulator

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🚀 Live Demo

https://selectiverepeatarq.vercel.app/

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🧠 What Is Selective Repeat ARQ?

Selective Repeat ARQ is a reliable data transfer protocol used in computer networks.
It enhances efficiency by retransmitting only the specific lost or corrupted packets, instead of resending the entire window (as in Go-Back-N).

This simulator visually demonstrates:

• Sender & receiver sliding windows
• Packet transmission
• ACK-based acknowledgement
• Packet loss & ACK loss
• Timer expiration
• Selective retransmissions
• Out-of-order packet buffering

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📘 How the Protocol Works (Diagram Explanation)

1. Sender Window

[ 0 ][ 1 ][ 2 ][ 3 ]       <-- Sliding Window (example: size 4)
   ↑     ↑     ↑
   |     |     |
 Sent  ACKed  Timer Running

2. Receiver Window

[ 0 ][ 1 ][ 2 ][ 3 ]
   ↑
Expected Packet

3. Packet Flow

Sender  --->  Packet(i)  ---> Receiver
Receiver --->    ACK(i)   ---> Sender

4. Loss Scenario Example

Packet(2) Lost
Timer for Packet(2) Expires
Sender Retransmits Packet(2)
Receiver Buffers Out-of-Order Packets

This diagram helps learners visualize the internal logic of Selective Repeat ARQ.

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🎯 Features

• Real-time sliding window animations
• Simulated packet & ACK loss
• Timer-driven retransmissions
• Out-of-order packet handling
• Receiver-side packet buffering
• Clean UI for education & demonstrations
• Highly interactive visualization

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📌 Use Cases

1. Education & Learning

Ideal for students studying computer networks and reliability mechanisms.

2. Classroom Demonstrations

Teachers can visually explain ARQ techniques.

3. Debugging Networking Logic

Helps learners experiment with real-time packet behavior.

4. Portfolio Showcase

Excellent project to demonstrate understanding of:

• Reliability protocols
• Sliding window mechanisms
• Network error handling

5. Research & Experimentation

Can be extended to compare:

• Selective Repeat ARQ
• Go-Back-N ARQ
• Stop-and-Wait ARQ

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🛠️ Tech Stack

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📂 Project Structure

├── index.html        # Main UI layout
├── style.css         # Styling and animations
├── main.js           # Core logic and simulation handling
└── README.md         # Documentation

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🤝 Contributing

Pull requests and suggestions are welcome.
Feel free to open an issue for discussions.

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📚 License

This project is open-source under the MIT License.