KTPSocket: Reliable Flow Control over Unreliable Channels

KTPSocket - Network Lab Project

(Source Code: KTPSocket Code)
(Visualization Dashboard: Live Dashboard)

This one was from our Networks Lab — we had to simulate a reliable message transmission protocol over UDP, basically a TCP-like behavior built from scratch. We called it KTPSocket, short for “Kharagpur TCP Socket.”

To test how reliable it was under different loss conditions, we plotted graphs to show how message delivery performance degrades as packet loss probability increases.

Objective

To emulate reliable end-to-end flow control over an unreliable communication medium (i.e., UDP). The system had to ensure:

• Message integrity and correct order
• Acknowledgment of received messages
• Retransmission on timeout
• No reliance on TCP — implemented entirely over raw UDP sockets

Graphs

Performance Analysis

Here’s what we observed:

• Impact of P: As loss rate (P) increases, the cost of reliable communication increases non-linearly. After P = 0.35, things start to go wild.
• ACK Efficiency: Even under high loss rates, ACK packets don’t grow as fast. That shows our protocol design is decently efficient.
• Network Load: Total load increases fast. At P = 0.50, it takes on average ~6 packets to deliver one message successfully. That’s a 6x overhead!

Final Thoughts

This lab was honestly one of the coolest — building your own reliable channel on top of UDP teaches you how TCP might be working under the hood. I had to tune the retransmission logic, timers, and loss handling multiple times to get consistent results.

Was fun to also create a dashboard with real-time plots and Wireshark captures.