> How can we implement some sort of internal roaming if we are not going
> to use a cenralized authentication server? That is, a.isp.com,
> b.isp.com and c.isp.com will contain the passwords of the users?
Use Secure Shell (ssh) and rdist to periodically transmit the users and/or
password files from one of the cities to all the others. The transfer
will be totally encrypted. What is going to be trickier is collecting,
concatenating, and processing the RADIUS accounting data. Or you can
use Merit.