What does the Data Link Layer primarily do?

The Data Link Layer is primarily responsible for passing data over physical network connections. This layer serves as an interface between the physical hardware of the network and the higher layers of the OSI model, specifically the Network Layer and the Transport Layer. It encapsulates data into frames and handles the physical addressing of those frames to ensure that data can be transmitted over the physical medium, such as Ethernet cables or wireless connections.

In this layer, significant tasks include managing error detection and correction, managing flow control, and ensuring that data packets are sent and received accurately across the physical layer. The Data Link Layer is essential for maintaining the integrity of data as it is transmitted, ensuring that errors introduced during transmission can be detected and potentially corrected.

The other roles described in the incorrect options fall under different layers of the OSI model or serve distinct functions outside of the Data Link Layer's primary responsibilities. For instance, routing packets is a function of the Network Layer, while verifying and sequencing packets is often managed by the Transport Layer. Similarly, hosting applications is a responsibility of the Application Layer, not the Data Link Layer. Thus, the choice of passing data over physical network connections accurately reflects the primary function of the Data Link Layer in the OSI model.