Product and Software: This article applies to all Aruba controllers running all versions of Aruba OS.
The big difference between WPA2 and WPA is that WPA2 provides fast roaming and preauthentication. WPA2 allows the wireless client and the wireless AP to cache the results of a full 802.1X authentication. The benefit of this caching is that if a client roams back to a wireless AP with which it has previously authenticated, the wireless client needs to perform only the 4-way handshake and determine new pairwise transient keys.
Also, WPA2 supports AES encryption keys, but WPA is restricted to TKIP