The portal user management is very flexible and allows you to use a variety of repositories for storing and retrieving user data. In particular, it allows you to leverage existing user repositories in your system rather than having to set up a new user repository.

For example, if you are using your portal in a system landscape that includes many non-SAP systems, you can provide a central user base using an LDAP directory and configure the portal to use the LDAP directory as its user repository.

On the other hand, if you are using your portal in a system landscape that consists of SAP systems only, you can set up Central User Administration (CUA) on one of the ABAP-based systems and configure your portal to use the ABAP user management as its user repository.