ADC AVIDIA SWD4573I1, User Manual

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ATM
20 Avidia System Configuration and Management User Manual
ATM
The following sections provide information on setting up an ATM network.
ATM Traffic Configuration
ATM traffic profiles are preconfigured combinations of traffic descriptors and related
parameters, which define the traffic Quality of Service (QoS) contract. Traffic profiles are used
to configure virtual circuits (VCCs and VPCs). During virtual circuit configuration you assign
a traffic profile to each circuit. Therefore, you must configure the ATM traffic profiles prior to
configuring any virtual circuits.
Adding an ATM Traffic Descriptor Profile requires you to specify a traffic type. The following
table provides an explanation of the traffic types currently supported by the Avidia system.
Traffic Type Description
Unspecified Bit Rate (UBR) UBR is a best-effort service that is best suited for LAN traffic. When
traffic congestion occurs, data is dropped. The Avidia system also
offers UBR service that includes a peak cell rate.
Constant Bit Rate (CBR) CBR is the highest quality of service, with a guaranteed constant
bandwidth. It is best suited for applications that transmit at a fixed
bandwidth, such as uncompressed voice and video, and circuit
emulation. When configuring CBR traffic, the specified peak cell rate
applies to both tagged and non-tagged cells. This traffic type does not
set the Cell Loss Priority (CLP) bit on transmitted cells that do not
conform to the quality of service contract.
Real-time VBR (rt-VBR) rt-VBR carries a variable bandwidth. It is well suited for real-time
services such as compressed voice and video which require stringent
cell transfer latency and less bursty traffic. It is not well suited for LAN
traffic due to the unpredictability of LAN traffic burst size.
Non-real-time VBR
(nrt-VBR) nrt-VBR carries variable bandwidth. It is well suited for data services
such as frame relay over ATM which requires guaranteed bandwidth
and lower Quality of Service. It is not well suited for LAN traffic due to
the unpredictability of LAN traffic burst size.