EAP-ttls reauthentification while roaming between bss

[Arjuna Scagnetto <arjuna () ts infn it>]

i read from "bulletproof wireless security"

"To connect to the new AP, the STA starts the connection procedure 
afresh. This means that the process of associating (and authenticating) 
to the new AP is the same as it is for STA that just powered on in this 
BSS. In other word the prior-Ap and the post-AP do not coordinate among 
themselves to achieve a handoff."

I would like to know if it still works in this manner or maybe the IAPP 
(or another protocol ) has improved and roaming between bss does not 
need reauthentification?

If roaming needs reauthentification, this process is done auto"magicaly" 
by the Operating System 
(linux-wpa-supplicant-Xsupplicant,macosx,winxp-SecureW2,vista) and then 
the station suffers only a momentarily lack of connection or the user 
needs to reinsert the credential?

p.s. i use EAP-ttls (pap) against LDAP (hash pass CRYPT-like) with a 
freeradius server.

thanks
Arjuna

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