Buffer Overflow

Buffer Overflow Simulator — Race Arrival Against Processing

When data arrives faster than a receiver can process it, the difference piles up in a buffer — and once the buffer is full, new data is dropped. This is what crashed the very first ARPANET message in 1969, when 'LOGIN' only got out 'LO'. This simulator lets you race an arrival rate against a processing rate and a finite buffer, watch the buffer fill and overflow, and see why the fix is flow control, not just a bigger buffer.

What you can do in this simulation

• Set the arrival rate, processing rate, and buffer size and watch the buffer fill live
• See data dropped the moment the buffer is full
• Load the 1969 'LOGIN' preset and reproduce the historic crash
• Learn why a bigger buffer only delays overflow when input is permanently faster
• Understand why flow control (slowing the sender) is the real fix — and why TCP has it

Concepts covered

buffer overflow · flow control · arrival rate · processing rate · packet loss · congestion · networking fundamentals

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