Troubleshooting Using A Subsystem Approach; Normal Router Startup Sequence; Identifying Startup Issues - Cisco ASR 9001 Hardware Installation Manual

Troubleshooting Using a Subsystem Approach

Troubleshooting Using a Subsystem Approach
To solve a system problem, try to isolate the problem to a specific subsystem. Compare the current router
behavior with the expected router behavior. Because a startup issue is usually attributable to one component,
it is most efficient to examine each subsystem, rather than trying to troubleshoot each router component.
For troubleshooting purposes in this chapter, the router consists of these subsystems:
• Power subsystem—Router chassis is shipped with up to two AC-input or DC-input power supply modules
• Chassis backplane power distribution—System transfers +12 VDC power from the power modules to
• Processor subsystem—Includes the active Route Processor (RP) card with line card. The RP is equipped
• Cooling subsystem—Consists of one fan tray with 14 fans, which circulate cooling air through the

Normal Router Startup Sequence

You can generally determine when and where the router failed during the startup sequence by checking the
status LEDs on the power modules and RP.
In a normal router startup sequence, this sequence of events and conditions occur:
Procedure
Step 1 The fan in each power module receives power and begins drawing air through the power supply.
The power module input power and output power indicators are on.
Step 2 The fans in the fan tray receive power and begin drawing air through the chassis.
The fan tray OK indicator is on.
Step 3
As the power-on and boot process progresses for the RP, the status of the RP appears on the front panel of
the card.

Identifying Startup Issues

The following table shows the LED states on the power modules (AC or DC), RP, and the fan tray after a
successful system startup.
Cisco ASR 9001 and Cisco ASR 9001-S Routers Hardware Installation Guide
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installed in the Cisco ASR 9001 Router chassis.
the chassis backplane and distributes it to all the cards through the backplane connectors. The fan tray
receives power from the chassis backplane and communicate to the RP CAN Bus controller.
with onboard processors. The RP downloads a copy of the Cisco software image to the line card processor.
chassis.
Troubleshooting the Installation