What function does the Transport layer perform in the OSI model?

The Transport layer's primary function within the OSI model is to break data into manageable chunks for transmission across the network. This segmentation ensures that large amounts of data can be handled more easily and efficiently. By dividing larger messages into smaller packets, the Transport layer can manage flow control and ensure that data is reassembled correctly at the destination.

This layer also provides services such as error detection and correction, ensuring that any data lost in transmission can be identified and retransmitted. In addition, the Transport layer is responsible for establishing, maintaining, and terminating communication sessions between devices, offering a reliable means of data transfer, particularly with protocols like TCP, which provides error-checking and guarantees that data arrives in order.

The other functions mentioned, such as managing encryption, moving packets between networks, and identifying devices, are handled at different levels of the OSI model. Encryption is typically managed at the Presentation layer, packet routing occurs at the Network layer, and device identification takes place at the Data Link layer. Thus, the focus on data segmentation at the Transport layer is key to its role in the OSI model.