Cisco 12008 Environmental Monitoring Facility - Cisco Gigabit Switch Router 12008 Installation And Configuration Manual

Cisco 12008 Environmental Monitoring Facility

Cisco 12008 Environmental Monitoring Facility
An environmental monitoring facility, called the maintenance bus (MBus), supports a
variety of functions essential to router operations. These functions include the following:
•
System discovery (enabling the router to identify installed components)
•
Booting software images
•
Supporting console traffic, logging functions, and diagnostic functions
•
Monitoring the operational health of the router and reporting error conditions
The MBus facility in the router is interconnected by means of the backplane to the
following components:
•
GRP
•
Line cards
•
CSCs
•
SFCs
•
Power supplies
Each of the components listed here contains an onboard MBus module that incorporates
two separate transceivers (A and B). Each transceiver has a separate etch (communication
path) through the backplane. Consequently, all the MBus modules in the system are reliably
interconnected to each other by means of redundant busses. This redundancy enhances the
reliablity of the entire environmental monitoring system.
The MBus module on each component is powered by +5.2 VDC that it receives through the
backplane from the power supply. A single MBus firmware image executes on all the MBus
modules present in the system.
The master MBus module on the GRP monitors all the alarm conditions detected by the
MBus modules in the other components of the system. The master MBus module then
determines an appropriate response to the alarm condition.
The MBus modules on installed components perform the following functions:
•
Power-up/down control—When power is applied to the router, the MBus module on the
GRP and the CSC immediately receive +5.2 VDC through the backplane from the
power supply, causing each card to supply power to its circuitry.
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Cisco 12008 Gigabit Switch Router Installation and Configuration Guide