scope:

Directory Service provides a means for locating essential information about network resources and their attributes. A directory service can avoid the cumbersome task of locating resources and services needed to handle the growth of interconnected networks, which are increasing in size, complexity, and diverse requirements. The ITU-T Recommendation X.500 Directory provides a general information sharing service utilizing a set of communication protocol facilities and a global name management infrastructure.

This standard specifies the usage of the ITU-T Recommendation X.500 Directory Service within the Telecommunications Management Network (TMN). The ITU-T Recommendation X.500 Directory operates in an Open Systems Interconnection (OSI) environment and uses the Association Control Service Element (ACSE) and Remote Operations Service Element (ROSE) of the OSI application layer. Additionally, implementations supporting replication use the Reliable Transfer Service Element (RTSE) of the OSI application layer.

This standard identifies the Directory Services needs of the TMN and addresses the Directory Service support for name to address mapping, specifically for an Application Entity (AE) title to facilitate association set up. This standard also examines some requirements for the Synchronous Optical Network (SONET) as a specific technology example in particular, including SONET transmission network elements (e.g., broadband cross-connects, wideband cross-connects, lightwave systems, add-drop multiplexers, repeaters, digital loop carriers, etc.) and SONET management systems (e.g., operation systems, mediation devices, element managers, etc.), that connect to the SONET Data Communications Network (DCN). Additional Directory Services needs for SONET and other specific technologies may be identified in the future. This standard serves as a basis for future extension of the usage of ITU-T Recommendation X.500 Directory Service for sharing information needed in the TMN for management of networks. This standard specifies Directory replication and use of Back-Up Directory Server (B-DS) as alternate methods for enhancing the reliability of the Directory Service.

This standard for Directory Service for TMN does not rely on any other profile, as no suitable International Standardized Profile (ISP) yet exists for the ITU-T X.500:2012 series of Recommendations upon which this standard is based. The model for the Directory Service for TMN is the model in International Telecommunication Union - Telecommunication Standardization Sector (ITU-T) Recommendation X.501, with the addition of a Registration Manager (RM) and Registration Agent (RA) to handle automatic registration of Network Element (NE) entries into the Directory under certain conditions.

The protocols for the TMN Directory Service are the Directory Access Protocol (DAP), Directory System Protocol (DSP), Directory Information Shadowing Protocol (DISP), and Directory Operational Binding Management Protocol (DOP) protocols specified in the X.500 series of ITU-T Recommendations. These protocols are to be used in conformance to the ITU-T X.500 Recommendations. Only the DAP is fully addressed in this standard, and its profile is provided in Annex B.1 The profiles for DSP, DISP, and DOP are planned to be added to this TMN Directory standard as needed in future expansions. A Registration Request Protocol (RRP) has been added for automatic registration. The application and profiling of DISP and DOP are for further study. This standard also does not fully address security.

The Directory object classes and attributes profiled for use in TMN are a subset of those defined in ITU-T Recommendations X.521 and X.520, plus a small number of TMN-specific objects and attributes defined here for the purposes of representing Network Elements and Operations Systems. This standard also identifies a set of structural object classes, their naming rules, and their naming attributes specified in the X.500 Recommendations. This is the minimum that shall be supported within the Directory Information Tree (DIT) commonly used within the TMN.