TCP Congestion Detection

What this TCP congestion detection question tests

This is an easy networking question that probes whether you understand the core mechanisms TCP uses to infer network congestion without explicit feedback from routers. It is foundational knowledge for systems engineers and anyone working on low-latency trading infrastructure or market-data pipelines.

To answer effectively, you should be able to identify and explain the key signals TCP interprets as congestion indicators, the algorithms that respond to those signals, and why TCP's inference-based approach (rather than direct notification) has become the standard. The question rewards clarity over depth—your answer should demonstrate that you can trace a connection's behaviour under stress.

• Packet loss and retransmission timeout mechanisms
• Round-trip time (RTT) and variance estimation
• Congestion window (cwnd) management and flow control
• TCP variants and their congestion response strategies