 |
 |
 |
 |
 |
|
|
|
|
|
Glossary
A nickname for a domain or host computer on the Internet.
A device that converts analog voice signals to a digital form and vice versa. In this context, analog signals are converted into the payload of UDP packets for transmission over the internet. The codec also performs compression and decompression on a voice stream.
Specifies messages for call control including signaling, Registration Admission and Status (RAS), and the packetization and synchronization of media streams.
A mode where the setup message contains all the information required by the network to process the call, such as the called party address information.
H.245 is a standard that provides the call control mechanism that allows H.323-compatible terminals to connect to each other. H.245 provides a standard means for establishing audio and video connections. It specifies the signaling, flow control, and channeling for messages, requests, and commands. H.245 enables codec selection and capability negotiation within H.323. Bit rate, frame rate, picture format, and algorithm choices are some of the elements negotiated by H.245.
Translates communication procedures and formats between networks, for example the interface between an IP network and the circuit-switched network (PSTN).
Manages a collection of H.323 entities (terminals, gateway, multipoint control units) in an H.323 zone.
The H.255.0 standard defines a layer that formats the transmitted audio, video, data, and control streams for output to the network, and retrieves the corresponding streams from the network.
H.323 is an ITU recommendation for a standard for interoperability in audio, video and data transmissions as well as Internet phone and voice-over-IP (VoIP). H.323 addresses call control and management for both point-to-point and multipoint conferences as well as gateway administration of IP Media traffic, bandwidth and user participation.
An endpoint that support conferences between three or more endpoints.
One or several digits dialed in front of a phone number, usually to indicate something to the phone system. For example, dialing a zero in front of a long distance number in the United States indicates to the phone company that you want operator assistance on a call.
The Q.931 protocol defines how each H.323 layer interacts with peer layers, so that participants can interoperate with agreed upon formats. The Q.931 protocol resides within H.225.0. As part of H.323 call control, Q.931 is a link layer protocol for establishing connections and framing data.
Real-time Transport Protocol. Provides end-to-end network transport functions suitable for applications transmitting real-time data such as audio, video or simulation data, over multicast or unicast network services. RTP does not address resource reservation and does not guarantee quality-of-service for real-time services.
RTP Control Protocol (RTCP). Works in conjunction with RTP to allow the monitoring of data delivery in a manner scalable to large multicast networks, and to provide minimal control and identification functionality. RTCP is based on the periodic transmission of control packets to all participants in the session, using the same distribution mechanism as the data packets.
See Voice Activation Detection (VAD).
In a SIP context, user agents (UAs) are appliances or applications, such as, SIP phones, residential gateways and software that initiate and receive calls over a SIP network.
Session Initiated Protocol. An ASCII-based, peer-to-peer protocol designed to provide telephony services over the Internet.
An IP telephony software architecture in which call control is done separately from IP Media stream control, for example, call control is done on the host and IP Media stream control is done on the board.
The encapsulation of H.245 messages within Q.931/H.225 messages so that H.245 media control messages can be transmitted over the same TCP port as the Q.931/H.225 signaling messages.
Voice Activation Detection. In Voice over IP (VoIP), voice activation detection (VAD) is a technique that allows a data network carrying voice traffic over the Internet to detect the absence of audio and conserve bandwidth by preventing the transmission of silent packets over the network.
|
|
|
|
|
Click here to contact Telecom Support Resources
Copyright 2003, Intel Corporation