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WTDC 2025

Directory Services for Multimedia

The H.350-series
The H.350-series describes a directory services architecture for multimedia conferencing and uses LDAP (Lightweight Directory Access Protocol) to store users’ voice, video and collaborative multimedia information in a way that integrates with directory and identity management systems already in place at universities, large enterprises and service provider networks. Extensions to support X.500 directory services are also available. H.350 enables providers to scale up video and VoIP operations from a few hundred endpoints to full enterprise and carrier level deployments. Account configuration details, authentication and authorization are linked to the enterprise directory using LDAP. Currently, the H.350-series comprises the following standards:
  • ITU-T Recommendation H.350 – Directory services architecture for multimedia conferencing - Describes a directory services architecture for multimedia conferencing using LDAP. Extensions have been made to also support X.500 directory services. Standardized directory services support association of individuals with endpoints, searchable directories (a.k.a. white pages), and clickable dialling. Directory services can also assist in the configuration of endpoints, and user authentication based on trusted data sources. H.350 also describes a standardized LDAP schema to represent endpoints on the network and associate those endpoints with users. It discusses design and implementation considerations for the interconnection of video- and voice-specific directories, enterprise directories, call servers and endpoints.
  • ITU-T Recommendation H.350.1 – Directory services architecture for H.323 – Describes LDAP and X.500 schemas to represent H.323 endpoints.
  • ITU-T Recommendation H.350.2 – Directory services architecture for H.235 - Describes LDAP and X.500 schemas to represent H.235 elements.
  • ITU-T Recommendation H.350.3 – Directory services architecture for H.320 - Describes LDAP and X.500 schemas to represent H.320 endpoints.
  • ITU-T Recommendation H.350.4 – Directory services architecture for SIP – Describes LDAP and X.500 schemas to represent SIP user agents.
  • ITU-T Recommendation H.350.5 – Directory services architecture for non-standard protocols – Describes LDAP and X.500 schemas to represent non-standard multimedia communications endpoints, and is meant to provide a very basic framework for representing these elements in a directory.
  • ITU-T Recommendation H.350.6 – Directory Services Architecture for Call Forwarding and Preferences - Describes simple LDAP and X.500 schemas to represent call forwarding and call preference information in an H.350 directory. It is intended to represent addresses to which calls should be forwarded in case an endpoint does not answer a call. It can also represent advanced functionality, such as directing a caller to a web page or email screen when the called endpoint is not available.
  • ITU-T Recommendation H.350.7 – Directory Services Architecture for XMPP - Describes LDAP and X.500 schemas to represent XMPP URIs and user information in the directory so that an organization can directory-enable and manage XMPP resources in the same way that other multimedia protocols (e.g. H.320, H.323, SIP) are managed in H.350.
  • ITU-T Recommendation H.351 - Semantic Web Interface for Multimedia Terminal and System Directories (SWIM-D) - Describes a semantic web interface in XHTML that can be used to provide directory lookup and menu capabilities for multimedia terminals and systems.
  • H.350-Series Implementer’s Guide – This document contains the latest updates, clarifications and defect fixes identified (but not yet formally incorporated) for the Recommendations of the H.350 Series.
Useful Links
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