What layer of the OSI model does the transport layer correspond to?

The transport layer corresponds to Layer 4 of the OSI model. This layer is responsible for providing reliable or unreliable delivery of data, as well as flow control, segmentation, and error recovery. The transport layer ensures that data is transferred reliably between host systems, allowing applications on those hosts to communicate effectively. Protocols commonly associated with this layer include TCP (Transmission Control Protocol) and UDP (User Datagram Protocol).

In contrast, Layer 2 refers to the data link layer, which focuses on node-to-node data transfer and handling error corrections at the physical layer. Layer 3 corresponds to the network layer, responsible for routing packets across networks and determining the best path for data. Layer 5, known as the session layer, manages sessions between applications, setting up, maintaining, and terminating connections. Therefore, the placement of the transport layer at Layer 4 is a fundamental aspect of understanding how data is handled in network communication.