What is the High-Level Data Link Control (HDLC) Protocol?

The High-Level Data Link Control (HDLC) Protocol is correctly identified as a bit-oriented synchronous data link layer protocol used for leased lines. HDLC operates at the data link layer of the OSI model, which is responsible for node-to-node data transfer and error detection and correction. It employs both control information and data within frames and manages the synchronization of the data being transmitted. This makes it particularly effective for point-to-point connections, such as leased lines, where reliable communication between two specific endpoints is essential.

The protocol encapsulates the data into frames, allowing for efficient error checking using cyclic redundancy checks (CRC). Additionally, HDLC supports both connection-oriented and connectionless services, enabling it to be flexible in various communication scenarios.

In contrast, options referring to packet-switching networks or address resolution methods (like ARP for Ethernet) are unrelated to the function HDLC serves in a direct point-to-point environment. Also, a file transfer protocol for Wide Area Networks (WANs) does not relate to the data link protocols but instead concerns higher-level operations such as TCP/IP or FTP, which operate at different layers of the OSI model.