Final answer:
The Data Link Layer utilizes the name frame for its protocol data unit (PDU). Frames encapsulate packets with additional information for node-to-node delivery over the physical network.
Step-by-step explanation:
The protocol data unit (PDU) used at the Data Link Layer in networking is known as a frame. When data is sent over the physical network, the Data Link Layer of the OSI model is responsible for the node-to-node delivery of the data. It takes packets from the Network Layer above, encapsulates them into frames, adds necessary header and trailer information to create the frames, and then sends it across to the physical layer for the actual transmission of data.
As part of the encapsulation process, the frame will typically contain source and destination hardware addresses, error-checking codes such as a Frame Check Sequence (FCS), and other necessary control information needed for reliable data transmission between directly connected nodes.