There is a growing list of Wi-Fi industry organizations and vendors that have developed hardware and software certifications.  Let's take a look at some of them.

The IEEE 802.11r amendment introduces a new 3-tier AKM architecture and some new terminology such as Mobility Domain, Key Holders, RICs, and two tiers of Pairwise Master Keys (PMKs).  A Mobility Domain is a set of BSSs, within the same ESS, identified by a Mobility Domain Identifier (a numerical value).  Fast BSS Transition (FT) is not specified between Mobility Domains.  The definition of an authenticator is, under the new amendment, split into two pieces – each being responsible for certain tasks.  These two pieces are called the PMK-R0 Key Holder (R0KH) and the PMK-R1 Key Holder (R1KH).  These could, in many instances, be considered the WLAN controller (R0KH) and the lightweight AP (R1KH) though this is not a requirement of the amendment.

The 802.11i amendment gave us Preauthentication and Pairwise Master Key (PMK) Caching.  Nothing fancy, just the basics.  Preauthentication enables supplicants (stations) to authenticate with authenticators (APs or WLAN controllers) to which they may roam.  Preauthentication always happens through the AP to which the station is currently associated – over the distribution system (typically an Ethernet network).

Having just written a whitepaper on Fast BSS Transition, I decided to look into the nuances of configuring supplicants for Opportunistic PMK Caching (OPC).  Holy smokes batman - what a pain it is to find documentation on this.  Microsoft says that OPC is supported when you have the KB893357 update loaded: http://support.microsoft.com/kb/893357

I was a little perturbed at 802.11n when I first started testing it, and now, after discovering the truth, I'm just saddened.