GBN Protocol Simulation

This repository contains Python programs that simulate the Go-Back-N (GBN) protocol.

Features

modifiedGBN.py: The program starts with the initial window size of 4. With every successful acknowledgement it increments the window size by 1 and with every frame loss it decreases the window size by half. Maximum allowed window size is 8 and minimum window size is 1. Then it creates a chart of Window Size vs Number of Sending Attempts.

originalGBN.py: Implements the original GBN protocol that always has a window size of 4. It always re-transmits the whole window of four frames if a packet loss happens. Then it creates a chart of Original GBN vs Modified GBN

How to Run

Clone the repository to your local machine.

git clone https://github.com/vmsaif/gbnProtocolSimulation.git

Navigate to the repository directory using your terminal.

Run the desired program.

python src/modifiedGBN.py

or

python src/originalGBN.py

What I Have Learned

• The basics of the GBN protocol and how it works.
• How to simulate the GBN protocol in Python using packet loss and acknowledgement mechanisms.
• How to plot a chart using the matplotlib library in Python.

Additional Information

• The programs use the random module to simulate packet loss with a chance of 35 percent.
• The programs use matplotlib to plot a chart showing the number of transmitted and received packets over time.
• It runs a simulation of 500 times.
• For the second graph where the comparison happens, modifiedGBN.py has to be run previously to generate it's data. Otherwise, it will use old data.

Dependencies

Python 3.x
matplotlib library for Python

Sample Chart Output

Modified GBN Protocol

Original GBN Protocol vs Modified GBN Protocol

Sample Program Output

Modified GBN Protocol

Original GBN Protocol