Cisco Systems Cisco XR 12416 manual Clock Scheduler Cards, Switch Fabric Cards

Chapter 1 Product Overview

Switch Fabric Overview

Caution Do not remove the blank filler panel unless instructed to do so by a Cisco support representative.

Clock Scheduler Cards

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).

Switch Fabric Cards

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 Router Installation Guide
OL-13833-01		1-17