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CiscoXR 12406 Router Installation Guide
OL-13831-01
Chapter1 Cisco XR 12406 Router Overview
Line Cards
The CSC contains the following functionality:
•System clock—The system clock synchronizes data transfers between line
cards or between the route processor and a line card, through the switch
fabric. In systems with redundant CSCs, the two system clocks ar e
synchronized so that if one system clock fails, the other clock takes over. The
system clock signal is sent to all line cards, the route processor, and switch
fabric cards.
•Scheduler—The scheduler handles requests from the line cards for a ccess 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 switch fabric carries the user traffic between line cards or
between the route processor and the line cards. The switch fabric card
contains only the switch fabric circuitry and receives scheduling information
and system clock information from the CSC.
The SFC contains only the switch fabric circuitry, which carries user traffic
between line cards or between the route processor and the line cards. The SFC
receives scheduling information and the system clock sent from the CSC.
Switch Fabric Switching Capacity and Router Type
The Cisco XR 12406 Router is based on a 10 -Gbps switch fabric, where each CSC
or SFC provides a 10-Gbps full-duplex connection to each line card in the system.
The 10-Gbps switch fabric consists of the Clock and Scheduler Card (product
number GSR6-CSC= for original fabrics, and 12406E-CSC= for enhance d fabric
versions) and the Switch Fabric Card (product number GSR6-SFC= for original
fabrics, and 12406E-SFC= for enhanced fabric versions). The 10-Gbps switch
fabric cards are labeled simply CSC and SFC.
Note You cannot mix 2.5-Gbps switch fabric cards and 10-Gbps switch fabric cards in
a chassis. The router will not operate with a mix of switch fabric card types.