Cisco Cisco IOS Software Release 12.2(8)T
SIP Media Inactivity Timer
Glossary
14
Cisco IOS Release 12.2(8)T and 12.2(11)T
Glossary
call—In SIP, a call consists of all participants in a conference invited by a common source. A SIP call
is identified by a globally unique call identifier. A point-to-point IP telephony conversation maps into a
single SIP call.
is identified by a globally unique call identifier. A point-to-point IP telephony conversation maps into a
single SIP call.
DSP—digital signal processor. Specialized computer chip designed to perform speedy and complex
operations on digitized waveforms. Useful in processing sound, such as voice phone calls, and video.
operations on digitized waveforms. Useful in processing sound, such as voice phone calls, and video.
Q.931—ITU-T Recommendation for signaling to establish, maintain, and clear ISDN network
connections. Recommendation for specifying the UNI signaling protocol in N-ISDN. Q.931 was
developed for out-of-band call control.
connections. Recommendation for specifying the UNI signaling protocol in N-ISDN. Q.931 was
developed for out-of-band call control.
QoS—quality of service. Measure of performance for a transmission system that reflects its transmission
quality and service availability.
quality and service availability.
RTCP—Real-Time Control Protocol. Monitors the QoS of an IPv6 RTP connection and conveys
information about the ongoing session.
information about the ongoing session.
RTP—Real-Time Transport Protocol. A network protocol used to carry packetized audio and video
traffic over an IP network.
traffic over an IP network.
session—A SIP session is a set of multimedia senders and receivers and the data streams flowing
between the senders and receivers. A SIP multimedia conference is an example of a session. The called
party can be invited several times by different calls to the same session.
between the senders and receivers. A SIP multimedia conference is an example of a session. The called
party can be invited several times by different calls to the same session.
SIP—Session Initiation Protocol. An application-layer protocol originally developed by the Multiparty
Multimedia Session Control (MMUSIC) working group of the Internet Engineering Task Force (IETF).
Their goal was to equip platforms to signal the setup of voice and multimedia calls over IP networks.
SIP features are compliant with IETF RFC 2543, published in March 1999.
Multimedia Session Control (MMUSIC) working group of the Internet Engineering Task Force (IETF).
Their goal was to equip platforms to signal the setup of voice and multimedia calls over IP networks.
SIP features are compliant with IETF RFC 2543, published in March 1999.
TDM—time-division multiplexing. A technique for transmitting a number of separate data, voice, and
video signals simultaneously over one communications medium by quickly interleaving a piece of each
signal one after the other.
video signals simultaneously over one communications medium by quickly interleaving a piece of each
signal one after the other.
VAD—voice activity detection. When enabled on voice port or a dial peer, silence is not transmitted over
the network, only audible speech. When VAD is enabled, the sound quality is slightly degraded, but the
connection monopolizes much less bandwidth.
the network, only audible speech. When VAD is enabled, the sound quality is slightly degraded, but the
connection monopolizes much less bandwidth.