PM8621-BI PMC-Sierra, Inc., PM8621-BI Datasheet - Page 24

• Manufacturer Part Number: PM8621-BI
• Description: Driver, NSE/SBS Narrowband Chipset Driver
• Manufacturer: PMC-Sierra, Inc.

Proprietary and Confidential to PMC-Sierra, Inc., and for its Customers’ Internal Use
Document ID: PMC-2021248, Issue 1
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Scalability
The CSD is designed to support 1- or 3-stage fabrics for applications that require higher
bandwidth (Figure 3 illustrates a 3-stage, and 2-depth fabric composed of NSE-20G and SBS lite
devices). The maximum bandwidth for a 3-stage fabric is 640 Gbps for NSE-20G fabric and 96
Gbps for NSE-8G fabric. There is no real theoretical limitation to a large switching core other
than physical limitation such as board size or heat dissipation. Please refer to Table 1 (NSE-20G)
and Table 2 (NSE-8G) for other possible configurations for a switching fabric with DS0
granularity. The current CSD implementation supports only 1-stage fabric.
Figure 3: Stage-3 Switch Fabric: 64 SBSLITEs, 6 NSE-20G, Bandwidth = 40 Gbps
Table 1: Narrowband Chipset Scalable Fabric with NSE-20G
Stage
1
3
3
It is important to note that typically, only one CSD instance should be configured to run the
OPA. (One exception is in the case of a 1+1 redundant fabric system where a second
(standby) copy of the OPA is allowed to run in parallel with the working copy.) The OPA
schedules calls in the fabric and keeps the record of all existing calls. It therefore acts as the
central repository for all the records. Since this CSD/OPA has to be aware of all devices in the
fabric, devices that are not local to this CSD/OPA must be added as “logical” devices. This
allows the CSD/OPA to properly recognize the existence of the SBS or NSE devices in the
fabric, though not directly under its control.
SBS-lite
SBS-lite
SBS-lite
SBS-lite
Depth
1
2
4
NSE-20G
NSE-20G
NSE-20G
1
6
12
(1,1)
(1,2)
Stage
NSE-20G
NSE-20G
(2,1)
(2,2)
SBS
32
64
128
NSE-20G
NSE-20G
Narrowband Chipset Device Driver Manual
(3,1)
(3,2)
Bandwidth (Gbps)
20
40
80
Narrowband Chipset Overview
SBS-lite
SBS-lite
SBS-lite
SBS-lite
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