Cisco Systems GSR12-SFC=, GSR12-CSC= manual Clock and Scheduler Card, Switch Fabric Card

Product Overview

Clock and Scheduler Card

The Cisco 12012 requires that one clock and scheduler card be installed in the lower card cage. You can add one additional clock and scheduler card for redundancy and to increase the amount of data able to be transferred between line cards. The clock and scheduler card contains the following functionality:

•System clock—Sent to all line cards, RP, and switch fabric cards. The system clock synchronizes data transfers between line cards or line cards and the RP through the switch fabric. In systems with redundant clock and scheduler cards, the two system clocks are synchronized. Should one system clock fail, the other clock takes over.

•Scheduler—Handles requests from the line cards for access to the switch fabric. When the scheduler receives a request from a line card for switch fabric access, the scheduler determines when to allow the line card access to the switch fabric.

•Switch fabric—The circuitry that carries the user traffic between line cards or between the RP and a line card. The switch fabric on the clock and scheduler card is identical to the switch fabric on the switch fabric card.

Note In a system configured with only one clock and scheduler card, the clock and scheduler card is installed in the second slot from the top in the lower card cage.

Switch Fabric Card

The switch fabric card contains only the switch fabric circuitry that carries the user traffic between line cards or between the RP and the line cards. The card receives scheduling information and the system clock from the clock and scheduler card. The card is keyed to occupy slots 2, 3, and 4 (lower three slots) in the lower card cage. The system can run without any switch fabric cards installed.

However, if you want to maximize the bandwidth and switching capacity of the system, you must install three switch fabric cards in the lower card cage.

Cisco 12012 Gigabit Switch Router Switch Fabric Cards Replacement Instructions 3