Chapter 3. H.323

H.323 is a standard for communication protocols from the International Telecommunications Union Telecommunication Standardization Sector (ITU-T); Version 4 is the current version. H.323 was created to provide multimedia communication across a packet network. The protocol can handle video and data, in addition to audio. H.323 interoperates well with the public switched telephone network (PSTN) in translating between call setup and control signals used in an IP network and those used in a switched-circuit network. H.323 is widely used in video conferencing deployments.

Gateways that use H.323 do not depend on a call agent, as with Media Gateway Control Protocol (MGCP). H.323 is the default gateway protocol on Cisco routers. This ...

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