PM8621-BI PMC-Sierra, Inc., PM8621-BI Datasheet - Page 29

• 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
Fabric Wiring Topology
The CSD is designed to take into account arbitrary wiring topologies between SBS devices and
the NSE core (Figure 6) in the system. However, designer should try to use the default, or
standard SBS/NSE wiring in the system. Non-standard wiring topologies increase the processing
overhead of the CSD.
In the case of a 3-stage fabric, the physical wiring between all NSE devices cannot be arbitrary
and must follow the “PMC-standard” NSE/NSE wiring scheme. This wiring standard is outlined
as follows: For the NSE switching core, the interconnection between all NSE devices is defined
below. The mapping specifies the core (stage 1) NSE connection associated with a given edge
(stage 0 or stage 2) NSE connection.
For the SBS-to-NSE connections, a SBS device must connect to the same port number of the two
NSE devices that are at the same depth.
For instance, if it is a 3-stage fabric made up of NSE-20Gs with depth 2, here is the “standard"
connection. NSE(x,y) specifies the NSE devices in the fabric with x denotes the stage and y
denotes the depth. SBS(z) specifies the SBS devices attached to the 3-stage NSE core.
NSE(1,0) incoming ports(0-15) connects to NSE(0,0) outgoing ports(0-15)
NSE(1,0) incoming ports(16-31) connects to NSE(0,1) outgoing ports(0-15)
NSE(1,0) outgoing ports(0-15) connects to NSE(2,0) incoming ports(0-15)
NSE(1,0) outgoing ports(16-31) connects to NSE(2,1) incoming ports(0-15)
NSE(1,1) incoming ports(0-15) connects to NSE(0,0) outgoing ports(16-31)
NSE(1,1) incoming ports(16-31) connects to NSE(0,1) outgoing ports(16-31)
NSE(1,1) outgoing ports(0-15) connects to NSE(2,0) incoming ports(16-31)
NSE(1,1) outgoing ports(16-31) connects to NSE(2,1) incoming ports(16-31)
SBS(0) transmit LVDS link connects to NSE(1,0) port 5
SBS(0) receive LVDS link connects to NSE(3,0) port 5
SBS(1) transmit LVDS link connects to NSE(1,1) port 20
SBS(1) receive LVDS link connects to NSE(3,1) port 20
depth(core) = NSEport(edge) / portsPerNSE
NSEport(core) = depth(edge) * portsPerNSE + NSEport(edge) / portsPerNSE
where portsPerNSE = NSEports / Depth. All divisions are integer division.
Narrowband Chipset Device Driver Manual
Narrowband Chipset Overview
29