Recommendation ITU-T X.518 | ISO/IEC 9594-4 specifies the procedures required for a distributed directory consisting of a mix of Directory System Agents (DSAs) and lightweight directory access protocol (LDAP) servers acting together to provide a consistent service to its users, independent of the point of access. It also describes procedures for protocol conversion between the directory access protocol/directory system protocol (DAP/DSP) protocols and the LDAP protocol.