What is a MAC Layer?

The MAC layer provides access control functions (such as addressing mode, access coordination, frame check sequence generation and checking, and LLCPDU delimitation) for the shared media PHY only with the support of the LLC layer. The MAC layer performs addressing modes and frame identification functions with the support of the LLC layer. The 802.11 standard uses CSMA / CA (Carrier Sense Multiple Access / Collision Prevention); the standard Ethernet uses CSMA / CD (Carrier Sense Multiple Access / Collision Detection). It is not possible to use the radio transceiver for both transmission and reception on the same channel. Therefore, 802.11 wireless LANs take measures only to avoid collisions, not to detect them. ^[1]