X.500

An international standard (1988) developed jointly by the International Organization for Standardization (ISO) and the ITU-T to support the e-mail name and address lookup requirements of X.400.

X.500 provides for global directory services that theoretically enable network managers to store information about all users, machines, and applications in a distributed fashion. X.500 is a very robust global directory standard that requires significant computational resources to implement and, therefore, is criticized for being over-engineered. See also e-mail, ISO, ITU-T, LDAP, X.400, and X Series.

• PSE (Power Sourcing Equipment)
• pseudonoise (PN)
• pseudoquaternary coding
• pseudorandom noise (PN)
• pseudowire
• pseudowire emulation edge to edge (PWE3)
• pseudowire emulation (PWE)
• PSK (Phase-Shift Keying)
• PSP (Payphone Service Provider)
• PSQM (Perceptual Speech Quality Measurement)
• PSQM+ (Perceptual Speech Quality Measurement plus)
• PSS1 (Private Signaling System No. 1)
• PSTN (Public Switched Telephone Network)
• PSTS (Public Switched Telephone System)
• PTE (Path Terminating Equipment)
• PTI (Payload Type Indicator)
• PTT
• PTT
• public data network (PDN)
• public domain
• public IP address
• public key encryption
• public key infrastructure (PKI)
• Public Safety Access Point (PSAP)
• Public Service Commission (PSC)