LLC
Logical Link Control
LLC provides a highly reliable ciphered logical link. This is achieved by providing a means of checking frame errors and signalling back to the originator for the purpose of retransmission. LLC therefore becomes an important link, especially when a mobile moves from one BSS (Base Station Subsystem) to another. LLC is also independent of the underlying radio interface protocols; a feature which was designed to enable an alternative GPRS radio solution, yet minimize the changes required to the NSS (Network Subsystem).