Reference: ASCP and ATP Functionality (Doc ID 813231.1)
Understanding DB Links Setup for APS Applications - ASCP and ATP Functionality (Doc ID 813231.1)
This doc is recommending to create PUBLIC DATABASE link using APPS account, which is a security issue. I tried setting up the database links as PRIVATE under APPS account on both EBS and ASCP instances, and the collections are working just fine. So, wondering why this doc is recommending PUBLIC link with huge security hole. With PUBLIC link, any user has full access to do whatever on the other instance through the link.