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A structured repository of informationon people and resources within an organisation, facilitatingmanagement and communication.On a LAN or WAN the directory service identifies allaspects of the network including users, software, hardware,and the various rights and policies assigned to each. As aresult applications can access information without knowingwhere a particular resource is physically located, and usersinteract oblivious to the network topology and protocols.To allow heterogeneous networks to share directoryinformation the ITU proposed a common structure calledX.500. However, its complexity and lack of seamlessInternet support led to the development of LightweightDirectory Access Protocol (LDAP) which has continued toevolve under the aegis of the IETF. Despite its name LDAPis too closely linked to X.500 to be "lightweight".LDAP was adopted by several companies such as NetscapeCommunications Corporation (Netscape Directory Server) andhas become a de facto standard for directory services.Other LDAP compatible offerings include Novell, Inc.'sNovell Directory Services (NDS) and MicrosoftCorporation's Active Directory. The Netscape and Novellproducts are available for Windows NT and Unixplatforms. Novell Directory Services also run on Novellplatforms. Microsoft Corporation's Active Directory is anintegral part of Microsoft's Windows 2000 and although itcan interface with directory services running on other systemsit is not available for other platforms.