What type of protocol is High-Level Data Link Control (HDLC)?

High-Level Data Link Control (HDLC) is categorized as a bit-oriented protocol. This means that HDLC operates at the bit level, manipulating individual bits in the data stream rather than larger data units such as bytes or messages. The bit-oriented characteristic allows HDLC to effectively manage frame delineation, error detection, and data integrity during transmission.

In HDLC, information is packaged into frames, which are structured in a way that allows for synchronization and control information to be inserted into the bit stream. This control is essential for reliable data communication across network boundaries. The use of bit-oriented techniques facilitates operations like bit stuffing, which ensures that specific bit sequences do not get confused with frame delimiters.

In contrast, message-oriented, packet-oriented, and byte-oriented protocols operate at different abstraction levels. Message-oriented protocols deal with entire messages as single entities; packet-oriented protocols handle packets composed of multiple bytes but focus on treating data as packets; byte-oriented protocols operate primarily with byte sequences. Each of these has its place in network communication, but they do not capture the granularity and functionality that bit-oriented protocols like HDLC provide.