High-Level Data Link Control (HDLC) is a bit-oriented code transparent synchronous data link layer protocol developed by the International Organization for Standardization (ISO). HDLC is used to connect one device to another. HDLC Protocol is used to send the data in the form of frames; a controller controls the flow of data in the data link layer of the OSI model. HDLC protocol is used to transmit frames in the logic link layer of the Data link Layer.
