Cisco ASR 901S Series Operating instructions

Troubleshooting
If you encounter problems while the router is in operation, use the information in this appendix to help isolate
problems or to eliminate the router as the source of the problem.
If you cannot locate the source of the problem, contact a customer service representative for information on
how to proceed. For technical support information, see the Cisco Information Packet publication that shipped
with your router. Before you call, have the following information ready:
•Chassis type and serial number
•Maintenance agreement or warranty information
•Type of software and version number
•Date you received the new chassis
•Brief description of the problem
•Brief explanation of the steps you took to isolate the problem
Ensure you provide the customer service representative with any upgrade or maintenance information that
was performed on the router after your initial installation.
Note
This appendix contains the following sections.
•Problem Solving , page 1
•Reading LEDs , page 4
Problem Solving
To solve a problem, isolate the problem to a specific subsystem by comparing the current router activity to
the expected router activity.
The LEDs on the bottom panel of the router enable you to determine router performance and operation. For
a description of these LEDs, see Reading LEDs , on page 4.
When solving a problem, check the following router subsystems:
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•Power and cooling systems—External power source, power cable, router power supply, and circuit
breaker. Also check for inadequate ventilation or air circulation.
•Modules—Checking the LEDs on the modules can help you to identify a failure.
•Cables—Ensure that the external cables connecting the router to the network are all secure.
Troubleshooting the Power and Cooling Systems
Corrective ActionPossible CauseSymptom
Check for an environmentally
induced shutdown. (See
Environmental Reporting Features,
on page 2.)
The cause is environmental.The System LED on the bottom
panel is not on.
Check the light pipe connection.Light pipe is not connected
properly.
•Check the DC or AC input.
•Check the DC or AC source.
The power source is not connected
properly.
The router shuts down after being
on for only a short time.
Check the chassis intake and heat
sink fins for obstructions. Clear any
obstructions.
The chassis intake and heat sink
fins are obstructed.
Check the environmental
specifications table in Table 3.
Installation does not meet
environmental site requirements.
Check the Management LED on
the front panel of the router. If the
LED is on, the power supply is
functional. If the LED is off, refer
to the Cisco Information Packet for
warranty information or contact
customer service.
There is a possible power supply
failure.
The router partially boots, but the
LEDs do not come on.
Environmental Reporting Features
The router has a temperature sensor to detect over temperature conditions inside the chassis. When over
temperature is detected it is reported to the processor as an interrupt, where the software generates the
appropriate alarms. If the router reaches a temperature of 248°F (120°C), the power supply cycles itself to
prevent the router from exceeding the maximum temperature while being powered up.
See the following table for help in interpreting environmental reporting features.
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Troubleshooting
Troubleshooting the Power and Cooling Systems

Corrective ActionPossible CauseSymptom
Take corrective steps. See the
environmental specifications table
in Product Specifications.
For over temperature alert settings,
see Environmental Monitoring
Temperature Sensor.
The air flow to the heat sink fins is
blocked.
The router operates at an
abnormally high temperature. The
following message appears on the
console screen:
%SYS-1-OVERTEMP: System
detected OVERTEMPERATURE
condition. Please resolve
cooling problem immediately!
Troubleshooting Cables and Connections
Network problems can be caused by a cable or cable connection, or external device such as a modem,
transceiver, hub, wall jack, WAN interface, or terminal. See the following table for information to help you
isolate the problem.
Corrective ActionPossible CauseSymptom
Check the router chassis or
software. For warranty information,
refer to the Cisco Information
Packet publication that shipped
with your router or contact
customer service.
The router does not boot properly.
The router constantly or
intermittently reboots.
The router is experiencing network
problems.
Verify that the parameters for your
terminal are set as follows:
•The terminal should have the
same data rate as the router
(9600 bps is the default).
•8 data bits.
•No parity generated or
checked.
•2 stop bits.
The router boots, but the console
screen is frozen.
There may be a problem with the
module or cable. For warranty
information, refer to the Cisco
Information Packet publication that
shipped with your order or contact
customer service.
The router powers on and boots
only when a particular cable is
disconnected.
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Troubleshooting
Troubleshooting Cables and Connections

Reading LEDs
The following table summarizes the LEDs on the chassis of the router. These LEDs are common to all chassis
models, however, these LEDs may be turned off using Cisco IOS CLIs. By default all three LEDs are enabled.
DescriptionColor/StateFunctionLED Label
System is in ROM Monitor
(ROMMON) mode
OffSystem status1
No hardware failure detected;
system is in Cisco IOS prompt
mode
Green
Minor hardware failure
detected
Amber
Major hardware failure (critical
temperature or voltage)
detected
Red
No powerOffManagement status2
System booted fine and is in
Cisco IOS prompt mode
Green
Software upgrade is in progress
(MCU or ROMMON)
Amber
Cisco IOS boot in progress or
in ROMMON mode
Red
Fast Ethernet port and slot not
connected
OffNetwork status3
Fast Ethernet port and
slot—link and line protocol is
up.
Green
Fast Ethernet port and
slot—administration is down
Amber
Fast Ethernet port and
slot—line protocol is down
Red
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Troubleshooting
Reading LEDs