In the seven-layer OSI model of computer networking, the physical layer or layer 1 is the first and lowest layer The layer most closely associated with the physical connection between devices. The transport layer controls the reliability of a given link through flow control, segmentation and desegmentation, and error control. It is Layer 4 of the OSI Model. Transport Layer provides transparent transfer of data between end-users, providing reliable data transfer services to the upper layers. Hence the correct answer is Data Link Layer. The main function of this layer is to make sure data transfer is error-free from one node to another, over the physical layer. The data link layer is responsible for the node-to-node delivery of the message.
This layer is the protocol layer that transfers data between nodes on a network segment across the physical layer. The data link layer, or layer 2, is the second layer of the seven-layer OSI model of computer networking.
