Cisco MWR 1941-DC Hardware Installation Guide
Troubleshooting
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Troubleshooting

Table Of Contents

Troubleshooting

Problem Solving

Troubleshooting the Power and Cooling Systems

Environmental Reporting Features

Troubleshooting Modules, Cables, and Connections

Reading the LEDs


Troubleshooting


Your Cisco MWR 1941-DC router goes through extensive testing before leaving the factory. If you encounter problems, use the information in this appendix to help isolate problems or to eliminate the router as the source of the problem.

This appendix contains the following sections:

Problem Solving

Reading the LEDs

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 have taken to isolate the problem

Problem Solving

The key to problem solving is to isolate the problem to a specific subsystem by comparing what the router is doing to what it should be doing.

The LEDs on the front panel of the router enable you to determine router performance and operation. For a description of these LEDs, see Reading the LEDs.

When problem solving, consider the following router subsystems:

Power and cooling systems—External power source, power cable, router power supply and circuit breaker, and router blower and fan. Also consider inadequate ventilation or air circulation.

Modules—LEDs on the modules help identify a failure.

Cables—External cables that connect the router to the network.

Troubleshooting the Power and Cooling Systems

Both the power LED and the fans can help you troubleshoot a power problem. Check the following items to help isolate the problem:

Check the following items to help isolate problems with the power supply installation:

With the MWR 1941-DC router connected to the power source, is the power LED on the front panel on?

If not, check the DC input, DC source, and the power supply wiring.

Check the power supply connection to the motherboard.

If the power LED is still off, the problem might be a power supply failure.

Does the router shut down after being on a short time?

Check the fans. If the fans are not working, the router will overheat and shut itself down.

If the fans are not working, check the power supply connections to the fans.

Ensure that the chassis intake and exhaust vents are clear.

Check the environmental site requirements in the "System Specifications" section.

Does the router partially boot, but the LEDs do not go on?

Check for a power supply failure by inspecting the power LED on the front panel of the router. If the power LED is on, the power supply is functional.

If the power LED is not on, refer to the Cisco Information Packet for warranty information or contact customer service.

Environmental Reporting Features

The MWR 1941-DC router has a temperature sensor to detect over-temperature conditions inside the chassis. The over-temperature detection trips at 75°C +/- 5%. This condition is reported to the processor as an interrupt and software then takes action on this interrupt to generate the appropriate alarming. If the router reaches a temperature of 90°C, the power supply will cycle to prevent the box from exceeding that temperature in a powered up state.

If the router is operating at an abnormally high temperature, you see the following message on the console screen:

%SYS-1-OVERTEMP: System detected OVERTEMPERATURE condition. Please resolve cooling problem 
immediately!

Some causes of abnormally high router temperature are:

Fan failure

Air conditioner failure in the room

Air blockage to cooling vents

Take steps to correct the problem. For information about environmental operating conditions, see "System Specifications" section.

Troubleshooting Modules, Cables, and Connections

Network problems can be caused by a module, cables or cable connections, or external devices such as a modem, transceiver, hub, wall jack, WAN interface, or terminal. Check for the following symptoms to help isolate the problem:

Module is not recognized by the router.

Make sure the module is firmly seated in its slot.

Check the LEDs on the module. Each module has its own set of LEDs. For information on these LEDs, see Reading the LEDs.

Make sure you have a version of Cisco IOS software that supports the module.

Module is recognized, but interface ports do not initialize.

Make sure the module is firmly seated in its slot.

Check external cable connections.

Make sure you have a version of Cisco IOS software that supports the module.

Router does not boot properly, or constantly or intermittently reboots.

Make sure the module is firmly seated in its slot.

Check the router chassis or software. Refer to the Cisco Information Packet publication that shipped with your router for warranty information, or contact customer service.

Router boots, but the console screen is frozen.

Check the external console connection.

Verify that the parameters for your terminal are set as follows:

(a) The same data rate as configured for the router (9600 bps is the default)

(b) 8 data bits

(c) No parity generated or checked

(d) 2 stop bits

Router powers on and boots only when a particular module is removed.

Check the module. Refer to the Cisco Information Packet publication that accompanied your order for warranty information, or contact customer service.

Router powers on and boots only when a particular cable is disconnected.

There may be a problem with the module or cable. Refer to the Cisco Information Packet publication for warranty information, or contact customer service.

Reading the LEDs

The LEDs on the front panel of the router enable you to determine router performance and operation. Figure A-1 shows the locations of the LEDs.

Figure A-1 Front Panel of the MWR 1941-DC

Table A-1 Chassis LEDs

LED
Color
Status

Power

Green

Operating voltages on the mainboard are within acceptable ranges.

Off

The router is not connected to a power supply or an error condition has been detected in the operating voltages.

Status

Green

The router's software has booted up and the system is operational.

Off

The router has not yet booted or an error condition has been detected in the boot process.

Activity

Green

Packets or idle contexts are being processed by the PXF.

Off

No PXF activity is occurring.


Table A-2 Fast Ethernet Connector LEDs

LED
Color
Status

Activity

Green

Data is being transmitted on the link.

 

Off

No data is being transmitted.

Speed

Green

100 Mbps communication speed attained.

 

Off

10 Mbps communication speed attained, or no link established.

Link

Green

Ethernet link is established.

 

Off

No established link.


Table A-3 VWIC LEDs

LED
Color
Description

Loopback

Amber

A loopback or line state is detected or is manually set by the user.

Off

Normal operation.

Alarm

Amber

A local or remote alarm state.

Off

Normal operation.

Carrier Detect

Green

A carrier has been detected and the internal DSU/CSU in the WAN interface card is communicating with another DSU/CSU. This LED is on during normal operation.

Off

No carrier has been detected.



Note In a redundant configuration, when the relays of the VWIC close, the Carrier Detect LED on the T1 ports will remain lit and the Alarm LED will go off. When the router is inactive, the ALARM LED will be lit (due to no framing) and the Carrier Detect LED will be off.



Note For information about the LEDs of network modules and WICs not covered in this appendix, see the Cisco Network Module Installation Guide and the Cisco Interface Card Installation Guide.