Primary administrative user
This ID is a member of the chosen repository, but also has special privileges in WebSphere Application Server. The privileges for this ID and the privileges that are associated with the administrative role ID are the same. The Primary administrative user name can access all of the protected administrative methods.
Bind dis name
This is the user who connects (bind) to LDAP. Should have enough permissions to read/write/search LDAP.
1. Both these users can be same
2. If you have multiple LDAPs connected then bind user name might be different on different LDPAs.