What does the transport layer do?

The transport layer is responsible for delivering messages between applications on different devices, ensuring that the communication is properly managed across the network. It plays a critical role in establishing connections between client and server programs, making sure that each piece of data is sent to the correct destination. The transport layer employs protocols like TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) to handle the flow of data, manage error detection and recovery, and maintain proper sequencing.

In this context, the transport layer's functionality includes multiplexing, which separates data streams from multiple applications. This capability is essential for the orderly receipt and transmission of data, allowing different applications on the same device to communicate over the same network connection efficiently.

Understanding this function highlights why the option about sorting out which client and server programs receive data is the correct one. It encapsulates the essence of the transport layer's responsibilities in managing communication between various applications.