H.323 is an ITU-T recommendation for multimedia conferencing over packet-based networks such as LANs and the Internet. H.323 is broad and comprehensive in its scope yet flexible and practical in its applicability. H.323 specifies components, protocols, and procedures for real-time point-to-point and multipoint multimedia communication over packet-based networks. It also sets interoperability guidelines for communication between H.323-enabled networks and the H.32X-based family of conferencing standards.
H.323 specifies protocols for real-time point-to-point audio communication between two terminals on a packet-based network that do not provide a guaranteed quality of service. The scope of H.323, however, is much broader and encompasses inter-network multipoint conferencing among terminals that support not only audio but also video and data communication.