H.323

H.323
H.323 is an industry-wide open standard for real-time audio, video, and data over
packet networks. H.323 is an International Telecommunication Union
Telecommunication Standardization Sector (ITU-T) standard and is part of the
H.32x family of protocols. H.320, transmissions over Integrated Services Digital
Network (ISDN), were discussed in Chapter 1. H.323 was built upon this protocol,
allowing video and audio transmissions to be supported over packet-based
networks such as Ethernet. Cisco’s IP telephony architecture can use H.323 to
communicate with IP phones, gateways, and, because it is an open protocol, it
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32 Chapter 2 • New World Technologies
can be used to communicate with dissimilar systems such as PBXs and other
vendors’ equipment. H.323 gateways will be discussed later in this chapter.