HDLC Some non-IEEE 802 protocols can be thought of as being split into MAC and LLC layers. For example, while HDLC specifies both MAC functions (framing of packets) and LLC functions (protocol multiplexing, flow control, detection, and error control through retransmission of dropped packets when indicated), some protocols such as Cisco HDLC can use HDLC-like packet framing and their own LLC protocol.
HDLC, Some non-IEEE 802 protocols can be thought of as being split into MAC and LLC layers. For example while HDLC specifies both MAC functions (framing of packets) and LLC functions (protocol, multiplexing, flow control, detection, and error control through retransmission of dropped packets when indicated) some protocols such as Cisco HDLC can use HDLC-like packet framing and their own LLC protocol.