Wireless Roaming Part 2 - PMK Caching and Preauthentication
Two methods of secure roaming were introduced in 802.11i-2004: PMK Caching and Preauthentication. PMK caching is a method of roaming used in an RSN that speeds up a roam back to about 50ms ms on average. Let’s take a look at how that works. The clients and APs will maintain a cache of PMKs. Therefore, if a client wants to roam back to an AP that it has recently been associated with both the client and the AP will already have the PMK in thier cache so the 802.11X/EAP proces