Network Layers

Understanding the OSI model layer where UDP and TCP operate

This question tests foundational knowledge of the OSI reference model and where common transport protocols sit within it. It is a straightforward conceptual check that appears in networking interviews, particularly at firms where systems engineers and quant developers need to reason about latency, packet routing, and protocol choice.

To answer questions in this area, you should be able to map protocols to their layers and understand what each layer's role is. Transport-layer protocols like TCP and UDP differ fundamentally in their guarantees: one prioritizes reliability and ordering, the other prioritizes speed. Knowing which layer they belong to is the first step toward understanding those trade-offs and why a trading system might choose one over the other.

• The seven-layer OSI model and its purpose
• Transport layer responsibilities and examples
• Contrast between connection-oriented and connectionless protocols