User Administration 
The user administrator performs all tasks that are relevant to user management and role assignments. In the portal, all user management functions related to users and groups are provided by the user management engine (UME). The UME is integrated in SAP NetWeaver Application Server (AS) Java and full documentation on the administration functions of the UME is available in the AS Java documentation.
For more information, see Administration of Users and Roles.
In this section, you can find information about concepts and functions that are unique or need additional clarification in an SAP NetWeaver Portal context.
Features
In a portal installation, the UME provides you with tools for performing user management tasks in a set of iViews and worksets integrated in the User Administration role in the portal