TCP Sliding Window Simulator
TCP, from Scratch
I rebuilt TCP by hand over raw sockets. The handshake, the sliding window, the retransmissions when packets vanish, all of it, with a live dashboard watching every packet move.
- Python
- Sockets
- TCP
Problem
You don’t really understand TCP until you’ve implemented the parts everyone takes for granted: connection setup, flow control, and what happens when packets vanish.
Approach
- Implemented the three-way handshake, adaptive sliding-window sizing, and packet retransmission from scratch over Python sockets.
- Built a real-time telemetry dashboard charting window size, throughput, and failed packets as the protocol runs.
- Stress-tested under high-bandwidth transfer, artificially lossy links, and abrupt client disconnects.
Result
A working protocol simulator that demonstrates flow control adapting live to network conditions — and a much deeper mental model of why production TCP behaves the way it does.