PM8621-BI PMC-Sierra, Inc., PM8621-BI Datasheet - Page 36

• 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 13: CAS Traffic Routing Across NSE/SBS Fabric
In-band Link Communication
In-band links are dedicated point-to-point communication links over LVDS. This in-band link
provides a clear channel for communication between devices located remotely from each other. It
is in place to facilitate shelf-to-shelf or rack-to-rack intercommunication. Sent at every frame
(125us), each message is 36 bytes long, with 2 bytes of header, 32 bytes for payload, and 2 bytes
for the CRC-16 trailer. The header bytes provide some near-realtime control signals between
devices to synchronize page switching, indicate switchover between working or protected links
and exchange three user defined signals (hardware) and 8 Auxiliary signals (software). The User
and Auxiliary signals can be used to indicate interrupts or can be used for handshaking between
the end point microprocessors. The CSD provides API for sending, receiving messages, and
manipulating the header bytes via the in-band links.
CAS reserved tributary
CAS DS0
destination tributary
(a)
soruce tributary
SPEx
SPEy
(b)
Fabric
NSE
Narrowband Chipset Device Driver Manual
SPEx
Narrowband Chipset Overview
(c)
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