Reliable Data Transfer Protocols Simulation

Overview

This repository contains C implementations of various reliable data transfer protocols used in computer networks. These protocols simulate packet transmission, acknowledgment handling, and error control mechanisms such as packet loss and retransmission.

Implemented Protocols

1. Go-Back-N (GBN) Protocol

• Implements a sliding window protocol where lost packets cause retransmission of all subsequent packets.
• Uses random packet loss simulation to test the retransmission mechanism.
• Features:
  • Sender transmits packets in a window.
  • Lost packets trigger retransmission from the lost packet onward.
  • Simulates acknowledgment receipt and window sliding.

2. Selective Repeat (SR) Protocol

• Implements a sliding window protocol that retransmits only lost packets instead of resending all.
• Uses a separate acknowledgment mechanism for each packet.
• Features:
  • Individual retransmission for lost packets.
  • Acknowledgment tracking for each frame.
  • Simulated transmission and acknowledgment process.

3. Stop-and-Wait Protocol

• Implements a simple ARQ (Automatic Repeat reQuest) protocol.
• Sender waits for an acknowledgment before sending the next packet.
• Features:
  • Simulates packet loss and acknowledgment loss.
  • Retransmits packets when acknowledgments are lost.
  • Ensures reliable packet delivery before proceeding to the next packet.

How to Compile and Run

Compilation

Use the GCC compiler to compile the C programs.

gcc -o gbn gbn.c
gcc -o sr sr.c
gcc -o stop_wait stop_wait.c

Running the Programs

Run the compiled executables with user input for parameters:

./gbn
./sr
./stop_wait

Dependencies

• C compiler (GCC recommended)
• Standard C libraries (stdio.h, stdlib.h, stdbool.h, time.h, unistd.h)

Example Usage

For the Stop-and-Wait protocol, enter:

Enter the number of packets to be sent: 5
Enter the probability of packet/ACK loss (scale: 0-1): 0.2

Output will simulate packet transmission and handling.

Contributing

Feel free to fork the repository, make improvements, and submit pull requests!

License

This project is open-source under the MIT License.