The Transport layer (Layer 4 of the OSI model) is responsible for providing mechanisms for data transfer sessions between hosts. It provides services such as connection-oriented data stream support, reliability, flow control, and error correction, all of which are essential for ensuring that data packets are transmitted reliably and in sequence. The Network layer primarily deals with logical addressing and routing, while the Data Link layer handles physical addressing, error notification, and ordered delivery of frames. The Physical layer deals with the transmission and reception of unstructured raw data over a network medium.