So, what's TCP?

What this networking fundamentals question tests

This is a straightforward easy-difficulty question that checks whether a candidate knows the basic terminology and layers of internet protocols. While the question itself is definitional, understanding TCP and its role in the networking stack is foundational for any systems engineer, infrastructure developer, or quantitative trader working with low-latency systems.

Quant shops and trading infrastructure teams often ask foundational networking questions early in interviews to establish that a candidate has hands-on familiarity with how data actually moves across networks. From there, deeper questions about latency, packet loss, congestion control, and protocol behaviour naturally follow. Mastery starts with knowing what the core protocols are and where they sit in the stack.

• OSI model layers and the transport layer
• Connection-oriented vs. connectionless protocols
• TCP vs. UDP trade-offs