Is the Cisco 1200 series access point considered a "thick AP" or a "thin AP" and why?
When set to autonomous mode, the Cisco 1200 acts as a stand-alone AP that is managed directly through its own GUI/CLI and performs all control functions without supervision. When upgraded to lightweight AP (LWAPP) mode, the Cisco 1200 is supervised by a Cisco WLAN Controller which provides centralized administration and carries out control plane tasks (like authentication and key caching) on behalf of all APs. These two modes are often referred to as "thick" (autonomous) and "thin" (lightweight).
However, distribution of functionality varies in various APs described as "thick" and "thin." The primary question is whether a WLAN controller is required to use the AP in a fully-functional way. Some APs that are mostly autonomous still rely on a central management console for configuration and monitoring – but that doesn't make them "thin." Similarly, some APs that work best when supervised by a WLAN controller can continue to work (with diminished capacity) if the controller becomes unreachable – but that doesn't make them "thick."
To decide whether an AP is thick or thin, look carefully at where control plane tasks are performed, including radio management, authentication, key caching, traffic filtering, and QoS enforcement. If another system is needed to perform control functions on behalf of all APs, those APs are to some extent "thin."
This was first published in June 2011