It is common to find a directories, in an administrative role, deployed within a single organization. These include network resource directories, such as an LDAP-based directory like Microsoft® Active Directory® directory service, Microsoft Windows® 2000 operating system directory service, and Novell NetWare Directory Services (NDS), as well as application-specific directories, such as Microsoft Exchange.
Multiple directories in the organization pose complex challenges to users, administrators, and developers. These problems have limited wide-directory deployment. End users face multiple logons and a variety of interfaces to information across multiple directories. Administrators face the complexity of managing multiple directories. End users and administrators want application developers to use an existing administrative directory, but developers face a dilemma about which one to use. Each directory offers unique application interfaces. A developer must choose a specific directory implementation, or support multiple versions of their application. As a result, developers rarely use existing directory services.