TCP Flow Control

Understanding TCP flow control mechanisms

This is an easy networking question that tests foundational knowledge of how TCP handles data transmission between sender and receiver. It appears frequently in interviews at quantitative trading firms, where engineers building market-data pipelines and order-management systems need to understand how TCP prevents a fast sender from overwhelming a slower receiver.

The question probes whether you can articulate the specific TCP feature that allows a receiver to communicate back to a sender about its capacity to accept data. Strong answers reference the protocol mechanics that let the receiver signal its readiness, not just the general concept of "slowing down." Understanding this mechanism is essential for diagnosing network bottlenecks and designing robust low-latency systems.

• Receiver-side buffering and capacity signalling
• Preventing packet loss due to buffer exhaustion
• The feedback loop between sender and receiver states