Pppoe + radius + transfer limit
FreeRADIUS support transfer limit down/up how can I seting up that ?
The user is only verified against radius on login. After this only accounting data for the session is send to the radius server. As the user is not rechecked you can't log him off. You might be able to make this work by using the CP for the users on top of this. This way the user won't be disconnected but you can throw him at a page that tells him his transferlimit is reached.
i have my own setup for pppoe and i've patched ppp with Session-Octets-Limit attribute but as i can see pfsense is using mpd i think you can try this patched version to limit session based on traffic: http://www.foggy.ru/soft/mpd/