Interim Accouting

[Ming-Ching Tiew]

May I know the common practise of radius accounting, it is 
common to expect the radius client to provide "interim" accounting,
ie it sends accounting info every so many seconds interval
before the session is closed ?

I just checked Coova chilli, it does it for the clients session
based on a configurable interval. But for the administrative
account of the NAS itself, it does not do any interim 
accounting.

Please comment.

Regards.