Which layer of the OSI model is responsible for end-to-end communication?

The Transport layer is responsible for end-to-end communication in the OSI model. This layer ensures that data is transferred reliably and in order from the source to the destination across a network. It plays a critical role in managing error detection and correction, flow control, and data segmentation.

Protocols commonly associated with the Transport layer, such as TCP (Transmission Control Protocol) and UDP (User Datagram Protocol), facilitate this communication. TCP, for example, establishes a connection-oriented communication channel that guarantees data delivery and order, while UDP offers a connectionless service that is faster but without reliability.

In the context of the OSI model, the function of the Transport layer is crucial because it operates above the Network layer, which deals primarily with routing packets of data between hosts, and below the Application layer, where end-user applications operate. This clear delineation allows the Transport layer to focus specifically on managing sessions and ensuring that the data gets to the correct application on the receiving end, regardless of the specifics of the underlying network infrastructure.