Go-Back-N ARQ — Visual Simulator

Concept: Go-Back-N ARQ is a sliding window protocol that allows the sender to transmit multiple frames before needing an acknowledgment (ACK) — improving efficiency.

🔹 How It Works

• Sender Window (N): The sender can send up to N unacknowledged frames.
• ACK Mechanism: The receiver sends cumulative ACKs — e.g., ACK 4 means it has received frames 0-4 correctly.
• Timeout: If no ACK arrives for the oldest unacknowledged frame, the sender retransmits all frames from that frame onwards.
• Loss Handling: You can simulate losses or delays for both frames and ACKs to observe the protocol’s behavior.

This simulator lets you visualize and control how Go-Back-N ARQ behaves under different network conditions.

⚙️ Controls Explained

• Number of Frames: Total frames to be sent in this session.
• Window Size (N): How many frames can be sent before an ACK is required.
• Timeout: Duration before retransmission starts if ACKs are not received.
• Frame Loss % / Mode: Simulate random or specific frame drops.
• Frame Delay: Introduce delays to observe timing differences.
• ACK Loss % / Mode: Simulate lost acknowledgments.
• ACK Delay: Delay ACK responses for realism.

🪄 Simulation Steps

1. Set all desired parameters (window size, losses, delays, etc.).
2. Click Start to run automatically or Step to go frame-by-frame.
3. Watch the animation: frames go sender → receiver, ACKs come back.
4. If a frame is lost or delayed, notice how the sender handles it.
5. At the end, view Event Log and Summary Diagram for detailed results.