Chapter 4 Troubleshooting the Installation
Problem-Solving with Subsystems
For troubleshooting purposes, the Cisco XR 12406 router consist of the following subsystems:
•Power subsystem—Includes the following components:
–AC-input or DC-input power distribution unit (PDU)
–AC or DC power entry modules (PEMs). The Cisco XR 12406 router can be configured for source AC or source DC power (you can not mix AC and DC power).
–Chassis backplane power distribution. The –48 VDC power from the power supplies is transferred to the chassis backplane, which distributes –48 VDC power to the cards in the card cages through the backplane connectors. The blower module receives power from the chassis backplane and passes MBus data back to the chassis backplane through a PDU connector.
DC-to-DC converters on the two alarm cards convert –48 VDC to
+5 VDC and put it back on the chassis backplane, where it is picked up to power the MBus modules on other cards and the blower module.
–DC-to-DC converters. Each card in the router is equipped with DC-to-DC converters. These converters are controlled by the MBus module on each card. The DC-to-DC converters take –48 VDC and convert it into the voltages required by the card circuitry.
•Processor subsystem—Includes the RP, up to five line cards (when no optional, redundant RP is installed) and two alarm cards. The RP downloads a copy of the Cisco XR IOS image to each line card processor. The system uses alphanumeric LED displays to display status and error messages, which can help in troubleshooting.
•Cooling subsystem—Consists of the blower module, which circulates air through the card cages to cool the cards, and the fan in each of the power modules, which circulates cooling air through the power module bays.
Caution Replace the blower module within 2 minutes of removing it from the chassis or the router will go into a critical failure mode and shutdown due to an overtemp condition.
| | Cisco XR 12406 Router Installation Guide | | |
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| OL-13831-01 | | | 4-5 |
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