Cisco Systems Cisco 12008 manual Housekeeping and Alarm Monitoring Functions of the CSC

Overview of the Cisco 12008

This single switch plane of the CSC can be used alone in a minimum router configuration, or it can be used in combination with another CSC and the three optional SFCs for full switching redundancy. In the latter case, the per line-card slot bandwidth of the router is increased from an OC-12 rate to an OC-48 rate, and the second CSC provides redundancy.

If any one switch plane fails in a fully redundant switch fabric, the failed plane is shut down, and the router’s full data bandwidth is carried by the surviving planes. The fault recovery cutover to another viable switch plane typically occurs without loss of data, because the data path defect is detected while redundancy information is still available, thus enabling error packets to be repaired “on the fly.”

Housekeeping and Alarm Monitoring Functions of the CSC

The section describes the following housekeeping and alarm monitoring facilities built into the CSC:

•MBus module— The MBus module on the CSC is a microprocessor-based subassembly that provides housekeeping services required during router power up and initialization. It also supports the alarm monitoring LEDs on the CSC faceplate, as described in the following section.

The MBus module on the CSC operates partly autonomously and partly under the control of the master MBus module on the RP.

A failed MBus module on the CSC is detected by an MBus polling algorithm running in the background on the RP.

A failed MBus module detected by this polling algorithm in a redundant CSC configuration causes the master MBus module to execute an administrative cutover to the MBus module on the surviving CSC. This cutover is accomplished with no disruption of normal system operations.

•Alarm monitoring and status functions—The CSC supports the router’s alarm and status monitoring functions. These functions are described in the following paragraphs. Figure 1-14 shows the location of the alarm contact connector and the various LEDs on the CSC faceplate through which the system accomplishes its alarm monitoring and status reporting functions.

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