Ericsson HL950 Administrator's Manual page 148

Multi Service Edge Device HL950
Administrator's Guide
BAS – Broadband Access Server
BER – Bit Error Rate
In a digital transmission, BER is the percentage of bits with errors divided by the total number of bits
that have been transmitted, received or processed over a given time period. The rate is typically
expressed as 10 to the negative power. BER is the digital equivalent to signal-to-noise ratio in an
analog system.
BLES – Broadband Loop Emulation Service
BRI – Basic-Rate Interface
The basic ISDN configuration, which consists of two B-channels that can carry voice or data at a rate
of 64 Kbps, and one D-channel, which carries call-control information. See also PRI.
CA – Certificate Authority
A trusted third-party organization or company that issues digital certificates used to create digital
signatures and public-private key pairs. CAs are a critical component in data security and electronic
commerce because they guarantee that the two parties exchanging information are really who they
claim to be.
CAS – Channel Associated Signaling
A form of circuit state signaling in which the circuit state is indicated by one or more bits of signaling
status sent repetitively and associated with that specific circuit
CBID – Circuit Bundle IDentifier
CBR – Constant Bit Rate
An ATM service category that supports a constant or guaranteed rate to transport services such as
video or voice as well as circuit emulation that requires rigorous timing control and performance
parameters
.
CDV – Cell Delay Variation
CDV is a component of cell transfer delay, induced by buffering and cell scheduling. Peak-to-peak
CDV is a QoS delay parameter associated with CBR and VBR services. The peak-to- peak CDV is the
((1-a) quantile of the CTD) minus the fixed CTD that could be experienced by any delivered cell on a
connection during the entire connection holding time. The parameter "a" is the probability of a cell
arriving late. See CDVT
CDVT – Cell Delay Variation Tolerance
ATM layer functions may alter the traffic characteristics of ATM connections by introducing Cell
Delay Variation. When cells from two or more ATM connections are multiplexed, cells of a given
ATM connection may be delayed while cells of another ATM connection are being inserted at the
output of the multiplexer. Similarly, some cells may be delayed while physical layer overhead or
OAM cells are inserted. Consequently, some randomness may affect the inter-arrival time between
consecutive cells of a connection as monitored at the UNI. The upper bound on the "clumping"
measure is the CDVT.
EN/LZT 108 5995 R3
June 2003
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B
C
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