JUNOS Internet Software Network Operations Guide: Hardware
The HCM has the following components:
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100-Mbps Fast Ethernet switch—Carries signals and monitoring data between router components.
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Two LEDs—Indicate HCM status. The green LED is labeled PWR and the blue
LED labeled MSTR . See “HCM LEDs” on page 435 for a description of the LED states.
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Alarm LEDs—Display alarm conditions, if any exist.
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PIC offline buttons—Relay a request to the CFEB, which prepares a PIC for removal from the router, or brings the PIC online when it is replaced.
Two HCMs are installed into the midplane from the front of the chassis, as shown in
Figure 174. 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.
Figure 174: M10i Router HCM Location
M10i front
HCM0
HCM1
The HCM is hot-pluggable.
HCMs
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Understanding the HCM
