Configuring EMC DD in Netbackup

Hi All

I need your suggestion what is the difference and best way to configure Data Domain in NBU , as my media server is UNIX server so which option is best OST plugin or NFS share as per my understandings in both Data Domain will perform the duplication task ,than why EMC DD is having two different option for connecting the NBU

I know this is not EMC support forum , but I thought may be some will handel this situation .

Regards

Rohit S Nayal