Network Router User Manual

For information about the pinouts for the connectors, see “Cable Connector
Pinouts” on page 199.
High-Availability Chassis Manager (HCM)
The High-Availability Chassis Manager (HCM) works with its companion Routing
Engine to provide control and monitoring functions for router components. The HCM
also displays alarm status and takes PICs online and offline.
Two HCMs are installed into the midplane from the front of the chassis, as shown
in Figure 1. The master HCM performs all functions and provides PIC removal buttons
for the first FPC. The standby HCM provides PIC removal buttons for the second FPC.
The HCM in the slot labeled HCM0 is paired with the Routing Engine in the slot labeled
RE0. Likewise, the HCM in the slot labeled HCM1 is paired with the Routing Engine
in the slot labeled RE1. By default, the HCM in the slot labeled HCM0 is the master.
NOTE: When HCM mastership changes because of failure, Routing Engine mastership
will change as well. For a description of Routing Engine mastership, see “Routing
Engine” on page 14.
The HCM performs the following functions:
■ Monitoring and control of router components—The HCM collects statistics from
all sensors in the system. When it detects a failure or alarm condition, it sends
a signal to the Routing Engine, which generates control messages or sets an
alarm. The HCM also relays control messages from the Routing Engine to the
router components.
■ Controlling component power-up and power-down—The HCM controls the
power-up sequence of router components as they start and powers down
components when their offline buttons are pressed.
■ Signaling of mastership—In a router with more than one Routing Engine, the
HCM signals to all router components which Routing Engine is the master and
which is the standby.
■ Alarm display—If an alarm exists, the HCM displays the alarm condition. For
more information, see “Alarm LEDs” on page 18.
■ PIC removal—If a PIC offline button is pressed, the HCM relays the request to
the CFEB, which takes the PIC offline and informs the Routing Engine. Other
PICs are unaffected, and system operation continues. For more information, see
“PIC Offline Buttons” on page 19.
HCM Components
Each HCM (shown in Figure 6) has the following components:
High-Availability Chassis Manager (HCM) ■ 17
Chapter 2: Hardware Component Overview