High-level Data Link Control

(H-D-L-C)

An OSI data link layer protocol that allows devices to both control data flow and correct data errors. HDLC sessions can be normal unbalanced (secondary only responds to a primary), asynchronous (secondary can also contact primary), asynchronous balanced (both primary and secondary stations send and receive over a duplex link). You might also see this as IBM's Synchronous Data Link Control (SDLC) and ANSI's Advanced Data Communications Control Protocol (ADCCP).

More Information

• HDLC Discussion
• HDLC Lecture