Clock Scheduler Cards; Switch Fabric Cards - Cisco Router XR 12416 Installation Manual

Chapter 1 Product Overview
Caution

Clock Scheduler Cards

Switch Fabric Cards

OL-17440-01
Do not remove the blank filler panel unless instructed to do so by a Cisco support
representative.
Clock scheduler cards provide the following functionality:
Scheduler—Handles all scheduling requests from the line cards for access to
•
the switch fabric.
System clock—Supplies the synchronizing signal to all SFCs, line cards, and
•
the RP. The system clock synchronizes data transfers between line cards or
between line cards and the RP through the switch fabric.
Switch fabric—Carries the user traffic between line cards or between the RP
•
and a line card. The switch fabric on the CSC is identical to the switch fabric
on the SFC.
The second CSC provides redundancy for the data path, scheduler, and reference
clock. Traffic between the line cards and the switch fabric is monitored constantly.
If the system detects a loss of synchronization (LOS), it automatically activates
the data paths on the redundant CSC so data flows across the redundant paths. The
switch to the redundant CSC occurs within sub-seconds (the actual switch time
depends on your configuration and its scale).
The switch fabric cards augment the traffic capacity of the router. SFCs contain
switch fabric circuitry that can only carry user traffic between line cards or
between the RP and the line cards. SFCs receive all scheduling information and
the system clock signal from the CSCs.
Cisco XR 12416 and Cisco XR 12816 Router Chassis Installation Guide
Switch Fabric Overview
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