Reg: GGSN support NAS and Freeradius.

Dear, I need clearification on freeradius and NAS (Coovachilli) with GGSN. It is possible to connect the NAS and FR to GGSN, NAS contact the FR through GGSN and NAS in between the internet and GGSN. I have some doubt especially on whether GGSN supports Coovachilli or not..? Please clearifiy my doubt .. Thanks & Best Regards, Malla.