Cisco Systems Cisco 12008 manual Switch Fabric of the Cisco

Overview of the Cisco 12008

Note The transmission speed of the Ethernet ports is auto-sensing by default and is user configurable.

Switch Fabric of the Cisco 12008

The heart of the Cisco 12008 is the switch fabric circuitry, which provides synchronized gigabit speed interconnections between the line cards and the RP. The switch fabric circuitry for the router is incorporated into two cards:

•Clock and scheduler card (CSC)—One CSC installed in the upper card cage is a standard (required) router component. The CSC represents one plane of switch fabric in the router. This card is described in greater detail in the section entitled “Clock and Scheduler Card.”

•Switch fabric card (SFC)—You can install a set of three optional SFCs in the lower card cage to increase its switching (data-handling) capacity). Each SFC card represents one plane of switch fabric in the router. This card is described in greater detail in the section entitled “Switch Fabric Cards.”

To achieve a fully redundant switch fabric with a switching capacity of 40 Gbps, you can install two CSCs and three SFCs in the router; the second CSC provides redundancy of CSC functions, as well as redundant switch fabric in the event of CSC or SFC failure.

Each CSC or SFC supports an OC-12 switching rate for the router (622 Mbps). By adding the set of three optional SFC cards, you can increase the switching capacity of the router to an OC-48 rate (2.4 Gbps).

Table 1-6 lists the switch fabric bandwidth and the switch card configurations needed to support an OC-12 switching rate or an OC-48 switching rate.

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