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's primary function is to ensure that data is sent reliably and accurately from the source to the destination across the network. It provides services such as segmentation of data, flow control, and error detection, which are critical for maintaining the integrity of the communication session.

In end-to-end communication, the Transport layer manages the establishment, maintenance, and termination of virtual connections between devices. For example, protocols like TCP (Transmission Control Protocol) operate at this layer, providing features like connection-oriented communication, which guarantees that packets arrive in order and without errors. Meanwhile, UDP (User Datagram Protocol) serves as a connectionless alternative, useful for applications where speed is preferred over reliability.

The other layers in the OSI model have different responsibilities; the Network layer focuses on routing data packets between devices, the Data Link layer deals with physical addressing and reliable local delivery, and the Application layer interacts directly with end-user applications. Each layer serves its purpose, but it is the Transport layer that specifically enables and manages the end-to-end communication aspect.