Which two layers of the OSI model correspond functionally to a single layer in the TCP/IP model?

The layers of the OSI model that correspond functionally to a single layer in the TCP/IP model are the Data Link and Physical layers. This relationship exists because the TCP/IP model condenses these two layers into a single Link layer.

The Link layer in the TCP/IP model encompasses the functionalities related to both Data Link and Physical layers of the OSI model. This includes the management of how data frames are physically transmitted over the network medium (Physical layer) and how those frames are structured and managed for reliable communication between devices connected on the same network segment (Data Link layer).

In the context of networking, the Data Link layer is primarily responsible for node-to-node data transfer and error detection, while the Physical layer involves the actual hardware transmission methods. Since the TCP/IP model is more streamlined, it combines these two functions into one, which reflects more practical implementations in network protocols and operations.