Which TCP/IP layer corresponds to the OSI model's Transport layer?

The TCP/IP layer that corresponds to the OSI model's Transport layer is indeed the Transport layer itself. In the OSI model, the Transport layer is responsible for providing end-to-end communication services for applications. This includes segmentation of data, flow control, error detection and correction, and reliability through protocols like TCP (Transmission Control Protocol) and UDP (User Datagram Protocol).

In the TCP/IP model, the Transport layer performs similar functions, ensuring that data is delivered from one application to another reliably and in the correct order. It allows applications on different devices to communicate over a network independently of the underlying physical infrastructure.

By understanding that the Transport layer in the TCP/IP model corresponds directly with the OSI model's Transport layer, one can see the alignment in roles and responsibilities at this level of the network architecture. The other layers mentioned, such as Application, Session, and Internet, serve different functions and do not correspond to the OSI Transport layer, as their roles pertain to higher-level services or network routing and addressing.