Cisco Gigabit Switch Router 12008 Installation And Configuration Manual page 68

Overview of the Cisco 12008
Table 1-7
Switch Card Type
One CSC
Second CSC
Three SFCs
1. Router equipped with one CSC and three SFCs.
2. Router equipped with two CSCs and three SFCs.
Switch Fabric Controller Functions of the CSC
In addition to providing one plane of switch fabric for the router, the CSC provides
numerous other functions and services essential to router operations. Figure 1-13 illustrates
the primary functional elements of the CSC.
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Cisco 12008 Gigabit Switch Router Installation and Configuration Guide
Switch Planes Provided by Switch Cards
Number
of Switch
Availability Planes
Standard 1
Optional 1
Optional 3
Description
A single CSC supports an OC-12 data rate
for the router, but provides no redundancy
in the router's switch fabric.
A second CSC supports an OC-12 data
rate for the router and also provides a
redundant plane of switch fabric. If one of
the CSCs fails, a fault recovery cutover to
the surviving CSC occurs, not only to
maintain the router's OC-12 data rate, but
also to preserve the system services
peculiar to the CSC.
The optional set of three SFCs enables the
router to support an OC-48 data rate. In an
1
OC-48 rate system, no redundancy exists
in the switch fabric. However, if a switch
plane failure occurs in a fully-redundant
system, a CSC can take over the functions
of either a failed CSC or a failed SFC, not
only to maintain the router's OC-48 data
rate, but also to preserve the essential CSC
system services.
2