Cisco Systems Cisco 12008 manual Clock and Scheduler Card

Overview of the Cisco 12008

Table 1-6	Switch Fabric Configurations
Switch Fabric		Number of	Number of	Planes of Switch
Bandwidth		CSCs	SFCs	Fabric
OC-12 nonredundant		11	0	1
OC-12 redundant		2	0	2
OC-48 nonredundant		1	3	4
OC-48 redundant		2	3	5

1. A CSC is a required router component.

A minimally configured router (one with a single CSC and no SFCs) supports an OC-12 data rate, but provides no redundancy of CSC functions. Adding a second CSC to a system, as well as the three optional SFCs, has the following effects:

•Increases the router’s bandwidth from an OC-12 rate to an OC-48 rate.

•Increases the number of planes of switch fabric available to the router from one to five (with the fifth serving as a redundant plane in the event of failure of a CSC or SFC.

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Provides full redundancy of CSC functions, such as the following:

—System clocking

—Resource allocation

—Scheduling

Provides full redundancy in the router’s fan power and alarm functions.

Clock and Scheduler Card

The CSC is a multi-function circuit board that can be installed in one or both of two reserved slots (CSC0 and CSC1) in the middle of the upper card cage (see Figure 1-2). The standard router configuration requires one CSC in either slot CSC0 or slot CSC1. If you configure your router with a single CSC, it is recommended that you install it in CSC1.

Each CSC is mounted on its own card carrier and incorporates an onboard power supply that takes the –48 VDC supplied by the backplane and converts it into the 3.3 VDC operating voltage required by the card’s electronics.

1-44Cisco 12008 Gigabit Switch Router Installation and Configuration Guide