Traffic volume accounting

Hello everyone, I am trying to implement traffic volume accounting in my Radius server. Is it possible to have a counter setup to achieve this? I've tested a lot and it seems freeradius is just ignoring my counter. I have somewhat managed to do some traffic accounting relying on external scripts, but it doesn't work properly. I'd like to know if someone has implemented realtime upload/download limitations and what methods were used. Thank you all!