How to control users traffic ?

Hi, Which is conventional way for checking online users traffic volume and disconnecting who reach to the limit of every user in freeradius: 1- using acct-interim packets to update output or input octets in sql and if user reach to the max of its accounting permission disconnect him/her.(Is there any patch to do this ?) 2- freeradius sends Session-Octets-Limit to the NAS and NAS can does this? 3- using billing softwares such as nibs . 4-other ways?