The Information field may be LLC, MAC or SMT protocol. FCS Frame check sequence. LLC type I service provides a datalink connectionless mode service, while LLC type II provides a connection-oriented service at the datalink layer. The LLC header structure is shown in the illustration below. Transmitter send sequence number.
Transmitter receive sequence number.
X Reserved and set to zero. M Modifier function bits. LLC information LLC data or higher layer protocols. ATM cells can be carried over many different physical media, from optical fiber to spread spectrum radio. ATM is not coupled to any particular physical layer.