Hope this helps:
SAP=Standalone (Autonomous AP)
LAP=LWAPP Access Point
CAP=Capwap Access Point
Q. What is CAPWAP?
A. In controller software release 5.2 or later, Cisco lightweight access points use the IETF standard Control and Provisioning of Wireless Access Points protocol (CAPWAP) in order to communicate between the controller and other lightweight access points on the network. Controller software releases prior to 5.2 use the Lightweight Access Point Protocol (LWAPP) for these communications.
CAPWAP, which is based on LWAPP, is a standard, interoperable protocol that enables a controller to manage a collection of wireless access points. CAPWAP is being implemented in controller software release 5.2 for these reasons:
To provide an upgrade path from Cisco products that use LWAPP to next-generation Cisco products that use CAPWAP
To manage RFID readers and similar devices
To enable controllers to interoperate with third-party access points in the future
LWAPP-enabled access points can discover and join a CAPWAP controller, and conversion to a CAPWAP controller is seamless. For example, the controller discovery process and the firmware downloading process when you use CAPWAP are the same as when you use LWAPP. The one exception is for Layer 2 deployments, which are not supported by CAPWAP.
You can deploy CAPWAP controllers and LWAPP controllers on the same network. The CAPWAP-enabled software allows access points to join either a controller that runs CAPWAP or LWAPP. The only exception is the Cisco Aironet 1140 Series Access Point, which supports only CAPWAP and therefore joins only controllers that run CAPWAP. For example, an 1130 series access point can join a controller that runs either CAPWAP or LWAPP whereas an 1140 series access point can join only a controller that runs CAPWAP.
For more information, refer to the Access Point Communication Protocols section of the configuration guide.
-Scott
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