At which layer of the OSI Model is TCP traffic encapsulated?

TCP operates at Layer 4, the Transport layer, where the protocol data unit is called a segment. The Transport layer is responsible for end-to-end communication, reliable delivery, flow control, and error recovery between hosts. TCP headers containing source/destination ports, sequence numbers, and flags are added at this layer before being handed down to Layer 3.

The Data-link layer (Layer 2) handles frame delivery between directly connected nodes using MAC addresses, not TCP segments.

The Application layer (Layer 7) provides network services to end-user applications and is above the Transport layer, not where TCP encapsulation occurs.

The Presentation layer (Layer 6) handles data formatting, encryption, and character encoding, not the encapsulation of transport protocols.