Network Protocols Simulation (C++)

A comprehensive simulation of Reliable Data Transfer (RDT) and TCP Congestion Control protocols, focusing on packet reliability, corruption handling, and network flow control.

🚀 Protocols Implemented

1. Reliable Data Transfer (RDT)

• RDT 2.2: Implements a stop-and-wait protocol that handles corrupted packets using checksums and ACKs with alternating sequence numbers (0 or 1).
• RDT 3.0: Simulates a channel with both packet loss and corruption. It features a multi-threaded timer implementation using std::mutex and std::condition_variable to handle retransmissions upon timeout.

2. TCP Congestion Control

• TCP Tahoe: Simulates the Slow Start and Congestion Avoidance phases. Upon detecting packet loss, the congestion window (cwnd) is reset to 1, and ssthresh is updated to half of the current cwnd.
• TCP Reno: Enhances the simulation by adding logic for Triple Duplicate ACKs. It distinguishes between timeouts (resetting cwnd to 1) and duplicate ACKs (performing fast recovery by setting cwnd to cwnd/2).

🛠️ Technical Implementation

• Checksum Logic: Validates data integrity by summing sequence numbers and ASCII values of the payload.
• Unreliable Channel: Simulates real-world network conditions using a transmit function with configurable loss and corruption probabilities (default set to 0.3).
• Concurrency: Utilized C++ threads in RDT 3.0 to manage non-blocking protocol timers.

📂 Repository Structure

• /Transport-Layer: C++ source code for RDT 2.2 and RDT 3.0.
• /Congestion-Control: C++ source code for TCP Tahoe and TCP Reno.
• /docs: Detailed assignment report containing logic analysis and output screenshots.

⚙️ How to Run

Compile the files using any C++11 compliant compiler. For RDT 3.0, ensure you link the pthread library:

g++ RDT_3.0.cpp -pthread -o rdt3
./rdt3