Hello Sameer,
If I understand it correctly then by replicating you mean to bring in/pull all the master data from SAP to Ariba. If yes, then there are couple of ways/channels to bring in/pull the master data from SAP/ERP to Ariba. Generally we use File Channel (ITK) or Web Services to pull the master data from SAP/ERP to Ariba. You can find more information about these channel/web services in Ariba Spend Management Configuration/Customization guide. Kindly refer it.
Regards,
Sandeep Jain