Recommendation ITU-T H.350.4 describes a lightweight directory access protocol (LDAP) directory services architecture for multimedia conferencing using a session initiation protocol (SIP). In particular, it defines an LDAP schema to represent SIP user agents (UAs) on the network and associate those endpoints with users.

This Recommendation is intended to supplement the CommObject directory architecture as discussed in Recommendation ITU-T H.350, and not intended to be used as a stand-alone architecture. The implementation of this LDAP schema, together with the use of the ITU-T H.350 CommObject architecture, facilitates the integration of SIP user agents and conferencing devices into the existing enterprise directories; thus allowing the user to perform white page lookups and access clickable dialling supported by SIP devices. The primary reasons for implementing this schema are identical to those listed in Recommendation ITU-T H.350 (the CommObject class definition) as they apply specifically to the use of SIP UAs.

This revised version of Recommendation ITU-T H.350.4 introduces several enhancements and clarifications to the previous version, primarily the addition of ITU-T X.500 directories support.

This Recommendation includes an electronic attachment containing a schema configuration file for SIPIdentity.