http://www.cisco.com/web/about/ac123/ac147/archived_issues/ipj_9-3/wireless_lan_switches.html
Two types of MAC implementations are possible with Fit APs, known as the Local MAC and the Split MAC architectures. Local MAC is where all the wireless MAC functions are performed at the AP. The complete 802.11 MAC functions, including management and control frame processing, are resident on the APs. These functions include time-sensitive functions (also known as Real Time MAC functions).
The Split MAC architecture divides the implementation of the MAC functions between the AP and the controller. The real-time MAC functions include functions such as beacon generation, probe transmission and response, control frame processing (for example Request to Send and Clear to Send—RTS and CTS), retransmission, and so on. The non-real time functions include authentication and deauthentication; association and reassociation; bridging between Ethernet and Wireless LAN; fragmentation; and so on.
Vendors differ in the type of functions that are split between the AP and the controller, and in some cases, even about what constitutes real time. One common implementation of a Fit AP involves local MAC at the AP and control and management functions at the AP.
split mac
http://www.cisco.com/en/US/docs/solutions/Enterprise/Mobility/emob30dg/TechArch.html#wp999574
CAPWAP Protocol
http://www.cse.wustl.edu/~jain/cse574-10/ftp/capwap/index.html
