NEC UNIVERGE SV9100 Manual page 35

Part 1: VoIP Reference Manual 35
PCM
Pulse Coded modulation.
QoS
Quality of Service. Measure of performance for a transmission system that reflects its transmission
quality and service availability. Standards based QOS for VoIP usually involves the implementation of
Ethernet standards 802.1p and 802.1q at layer 2 across an Ethernet. At layer 3, the IP standard
Diffserv defines bits settings in the TOS (type of service) in the IP header which will identify packets
as being associated with a specific service.
RSVP
Resource Reservation Protocol. Protocol that supports the reservation of resources across an IP
network. Applications running on IP end systems can use RSVP to indicate to other nodes the
nature (bandwidth, jitter, maximum burst, and so forth) of the packet streams they want to receive.
RSVP depends on IPv6. Also known as Resource Reservation Setup Protocol.
RTP
Real-Time Transport Protocol. Real-Time Transport Protocol. One of the IPv6 protocols. RTP is
designed to provide end-to-end network transport functions for applications transmitting real-time
data, such as audio, video, or simulation data, over multicast or unicast network services. RTP
provides services such as payload type identification, sequence numbering, time-stamping, and
delivery monitoring to real-time applications.
RTCP
RTP Control Protocol. Protocol that monitors the QOS of an IPv6 RTP connection and conveys
information about the on-going session. See also RTP.
SIP
Session Initiation Protocol; A protocol that provides telephony services similar to H.323, but is less
complex and uses less resources.
TCP (Transmission Control Protocol)
Connection-oriented transport layer protocol that provides reliable full-duplex data transmission. TCP
is part of the TCP/IP protocol stack.
TOS
Type of Service; A method of setting precedence for a particular type of traffic for QoS.
Trunk
A communications channel between two points, typically referring to large-bandwidth telephone
channels between switching centres that handle many simultaneous voice and data signals.
TDM
Time-division multiplexing. In TDM, information from each data Channel is allocated bandwidth based
on preassigned time slots, Regardless of whether there is data to transmit.
TOS
Type of Service.
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