Carrier Access Broadmore 1750 - Manual (Page 406)

Glossary-8 Broadmore 1750 - Release 4.6
Glossary
Quality of Service (QoS)
A QoS class can have specified performance parameters (specified QoS class) or no specified
performance parameters (unspecified QoS class). QoS classes are inherently associated with a
connection. A specified QoS class specifies a set of performance parameters and the objective
values for each performance parameter identified. Examples of performance parameters that
could be in a QoS class are:
1. Cell Loss Ratio
2. Cell Transfer Delay
3. Cell Delay Variation
A specified QoS class provides a quality of service to an ATM virtual connection (VCC or
VPC) in terms of a subset of ATM performance parameters defined in Section 3 of Appendix
A of the ATM Forum UNI v3.1 specifications. Initially, each service provider should define
objective values for a subset of the ATM performance parameters for at least one of the Service
Classes (Service Class A, B, C, or D) from ITU-T recommendation I.362 in a reference
configuration that may depend on mileage and other factors.
QoS Classes are currently defined as:
Class 1: supports a QoS that will meet Service Class A performance requirements
(circuit emulation, constant bit rate video). Should yield performance
comparable to current digital private line performance.
Class 2: supports a QoS that will meet Service Class B performance requirements
(variable bit rate audio and video). Intended for video and audio in
teleconferencing and multi-media applications using packets.
Class 3: supports a QoS that will meet Service Class C performance requirements
(connection-oriented data transfer). Intended for interoperation of
connection-oriented protocols, such as Frame Relay.
Class 4: supports a QoS that will meet Service Class D performance requirements
(connectionless data transfer). Intended for interoperation of
connectionless protocols, such as IP or SMDS.