H.323

(redirected from H.323 protocol)

H.323

(communications, standard)
The ITU-T standard for sending voice (audio) and video using IP on a LAN without QoS.

H.323 includes Q.931 for call setup, H.225 for call signalling, H.245 for exchanging terminal capabilities, RTP/RTCP for packet streaming, G.711/G.712 for CODECs, and several other protcols, many of which need to be negotiated to setup a simple voice call.

The complexity of H.323 has lead to the IETF proposing the simpler alternatives SIP and MGCP/Megaco.

H.323

An ITU standard for real-time voice and videoconferencing over packet networks, including LANs, WANs and the Internet. Although H.323 is a very comprehensive standard that supports voice, video, data, application sharing and whiteboarding, the parts relating to audio protocols have been widely used for IP telephony applications.

H.323 defines various elements including media gateways for conversion to packets, gatekeepers for call control and multipoint control units (MCUs) for conferencing. Following are the various protocols referenced under the H.323 umbrella. See videoconferencing, codec, H.225, H.245, IP telephony, gatekeeper, SIP and MGCP/MEGACO.

Standard Function

   G.711      Audio codec
   G.722      Audio codec
   G.723      Audio codec
   G.728      Audio codec
   G.729      Audio codec

   H.261      Video codec
   H.263      Video codec
   H.264      Video codec

   H.225      Call control
   H.245      Control messages
   Q.931      Connection messages
   RAS        Control channel

   T.120      Data collaboration
References in periodicals archive ?
RADVISION (Nasdaq:RVSN), an industry leader in providing a wide range of development solutions for voice, video, and data collaboration over IP and 3G, recently announced the general availability of its new H.
323 and SIP-functionality in the eConf products were developed using RADVISION's Development Platforms and underlying SIP and H.
RADVISION (Nasdaq:RVSN), the industry leader in providing a wide range of development solutions for voice, video, and data collaboration over IP and 3G, today announced the general availability of its new H.
Based on usage feedback, RADVISION enhanced its new H.
The PSTN card and the IP card with support for the H.
Siemens Enterprise Networks, a subsidiary of Siemens AG (NYSE:SI) and a leading provider of converged voice and data solutions, today announced that its HiPath(TM) enterprise convergence architecture will support the industry standard Session Initiation Protocol (SIP) in addition to continuing support for the popular H.
Open H323 is an Open Source implementation of the ITU H.
The OpenH323 is a highly regarded, commercial-quality open-source H.
Founded in 1999, SoftJoys Labs develops a full range of products targeted at VOIP and Internet Telecommunications software, including ITU H.
The product, result of the Hughes Software Systems (HSS) partnerhsip, uses HSS's Protoquick H.