S/UNI®-ATLAS-3200 Telecom Standard Product Data Sheet
Preliminary
5
Application Examples
The S/UNI®0 ATLAS-3200 device is an integrated circuit that implements the ATM Layer
functions that include header translation, cell rate policing, performance management and fault
management. The S/UNI-ATLAS-3200 device is a uni-directional part. When used in the ingress
direction, it is intended to be situated between the physical layer (PHY) devices and a traffic
manager (which schedules traffic into the switch fabric). When used in the egress direction, it is
intended to be situated between a traffic manager (which shapes traffic out of the switch fabric)
and the PHY devices. This application is shown in the figure below.
Figure 1 S/UNI-ATLAS-3200 Application
UTOPIA or POS-PHY (Level 3)
Ingress Direction
Ingress Mode
Traffic
S/UNI-ATLAS-3200
Manager
(+SRAM)
Switch
16 bit SCI PHY (Backward
Cell Interface)
PHY
Fabric
Egress Mode
S/UNI-ATLAS-3200
(+SRAM)
Traffic
Manager
Egress Direction
5.1
Cascading
Multiple S/UNI-ATLAS-3200 devices can be cascaded when more than 64K VCs are required.
In a configuration with “n” cascaded devices, each device is configured (using the per-PHY
Processing register) to only process cells from some of the 48 possible PHYs (the PHYs meant
for that device). Cells from the other PHYs (which the device has been told to not process) will
be passed through. A passed through cell will have already been processed by an upstream device
in the cascade, or will be processed by a downstream device. When cascading, each PHYs cells
will be processed in exactly one device and will be passed through all the other devices.
Such cascading allows the total number of VCs supported to be “n” times 64K where “n” is the
number of cascaded devices (and the 48 available PHYs are partitioned among the “n” devices).
In each device, the 64K VCs that it has available are shared between all the PHYs that it is
processing. Cascading does not result in an increase in aggregate throughput.
Proprietary and Confidential to PMC-Sierra, Inc., and for its Customers’ Internal Use
Document ID: PMC-1990553, Issue 4
32
PMC [ PMC-SIERRA, INC ]
