PM8621-BI PMC-Sierra, Inc., PM8621-BI Datasheet - Page 35

• 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
Figure 12: Doubled SBS and NSE Fabric – 20Gbps Aggregate Bandwidth using Two NSE-20G
CAS Traffic Routing
When routing CAS traffic through the fabric, the DS0s has to be first packed into a tributary with
CAS processing enabled, (The assumption is the DS0s fills a T1/E1 virtual tributary. Multiple
tributaries are required if there are more DS0s than a tributary can hold) and then switched as a
whole across the NSE space switch fabric to the destination SBS. This is deemed necessary
because only SBS has the ability to process CAS. The concept of a CAS route across the fabric is
introduced as a result when routing CAS traffic across the fabric.
A CAS route can be viewed as a channel setup for CAS traffic between the two SBSs. All CAS
DS0 traffic is first routed to the CAS reserved tributaries (Figure 13) before going through the
NSE space switch to the same CAS reserved tributaries in the output SBS. The traffic is then
routed to the destination tributary from the reserved tributary on the output SBS side.
The CSD automatically handle all aspects of CAS traffic routing and is transparent to the user.
Currently, the CSD does not support a mixture of T1 and E1 CAS traffic in the fabric.
SBS #31A
SBS #31B
SBS #0A
SBS #0B
Transmit
Transmit
Transmit
Transmit
31
31
0
0
NSE-
NSE-
20G
20G
0
31
31
0
SBS #31A
SBS #31B
SBS #0A
SBS #0B
Receive
Receive
Receive
Receive
ODATA_A
other signals_A
ODATA_B
other signals_B
ODATA_A
other signals_A
ODATA_B
other signals_B
OPL_A
OPL_A
OPL_B
OPL_B
Narrowband Chipset Device Driver Manual
1
0
1
0
Narrowband Chipset Overview
MUX
MUX
other signals
other signals
ODATA
ODATA
OPL
OPL
35