Reliable File Transfer System

This project implements a reliable file transfer protocol using UDP with features such as acknowledgments, retransmissions, timeouts, and packet reordering. It consists of a sender, receiver, and a network simulator that introduces loss, corruption, and reordering for testing.

Requirements

• Python 3.x

File Descriptions

• sender.py - Sends a file to the receiver in chunks, implementing reliability mechanisms.
• receiver.py - Receives packets, handles reordering, and writes the received file to disk.
• network_simulator.py - Simulates packet loss, corruption, and reordering.
• utils.py - Contains helper functions and constants for packet handling.
• launcher.py - Automates the process of starting all components.

How to Run

Running with launcher.py (Recommended)

To automatically start all components, run:

python launcher.py

Follow the prompts to specify the input file and output file.

Running Manually

Step 1: Start the Network Simulator

python network_simulator.py

Step 2: Start the Receiver

python receiver.py output_file

Replace output_file with the name of the file to be saved.

Step 3: Start the Sender

python sender.py input_file

Replace input_file with the file you want to send.

Example Usage

Example 1: Using the Launcher

python launcher.py

• Input file: example.txt
• Output file: received_example.txt

Example 2: Running Manually

python network_simulator.py &
python receiver.py received_image.jpg &
python sender.py image.jpg

This will transfer image.jpg to received_image.jpg via the simulated network.

Notes

• The network simulator introduces packet loss, corruption, and reordering for testing reliability.
• Ensure that all components are running before starting the sender.
• The receiver will reconstruct the file and write it to disk after receiving all packets.