H.323
H.323 is an ITU-T standard protocol suite for multimedia communication over packet-based networks, such as IP networks. It defines how audio, video, and data conferencing are transmitted and managed, including call setup, control, and teardown. Originally developed for video conferencing over LANs, it has been widely used in VoIP and unified communications systems.
Developers should learn H.323 when working on legacy or enterprise video conferencing systems, VoIP implementations, or interoperability projects with older telecommunication equipment. It is particularly relevant in scenarios requiring standardized communication across different vendors' devices, such as in corporate or educational settings, though it has been largely superseded by newer protocols like SIP in modern applications.