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Troubleshooting

Troubleshooting

There are several ways to troubleshoot problems associated with installation and performance. For instance, the LEDs on the front panel are the quickest way to evaluate the operation of the switch. The statistics provided by the management console or SNMP management station can provide more details about the cause of connectivity and performance problems. In addition, the power-on self-test (POST) determines if the switch is functioning properly when powered up. If the switch does not operate properly or you are unable to access the management console, you can try to resolve these problems by using the diagnostic console.

Potential problems are discussed under the following topics in this chapter:

Understanding POST Failures

The 13 tests in POST detects nonfatal and fatal failures when the switch is powered up. Additional information about how the switch runs POST is provided in the "Verifying Your Installation Using the Power-On Self-Test" section in the "Installation" chapter.

If your switch has a fatal failure, the switch is not operational and the management console is not available. Contact your Cisco sales representative.

If a nonfatal failure occurs, the SYSTEM LED turns amber. A POST failure message, such as the one in Figure 4-1, is displayed on the Management Console Logon Screen. In this example, the switch indicates that ports 1x to 8x and port Ax (or port A) failed POST
test 1 (nonfatal--port loopback test).


Figure 4-1: Example of a POST Failure Message
Catalyst 2820 Management Console
Copyright (c) Cisco Systems, Inc.  1993-1997
All rights reserved.
Ethernet address:      00-E0-1E-7E-B4-40
PCA Number: 73-2239-01
PCA Serial Number: SAD01200001
Model Number: WS-C2822-EN
System Serial Number: FAA01200001
-------------------------------------------------
*** Power On Self Test (POST) failed ***
*** Failed Test(s): 1
*** Failed Port(s): 1 2 3 4 5 6 7 8 A
1 user(s) now active on Management Console.
Press any key to continue.

Table 4-1 lists the individual POST tests that are executed by the switch. This table also describes the failures (nonfatal and fatal) that can be detected during POST and provides information on what the switch does or what you can do if a fatal or nonfatal failure is detected.


Table 4-1: POST Test Descriptions
Port Status
LEDs
Post Tests
16x Fatal--ECU DRAM test. Switch is not operational. Contact Cisco Systems.
15x Not used during POST.
14x Not used during POST.
13x Not used during POST.
12x Fatal--Forwarding engine test. Switch is not operational. Contact Cisco Systems.
11x Fatal--Forwarding engine SRAM test. Switch is not operational. Contact Cisco Systems.
10x Fatal--Packet DRAM test. Switch is not operational. Contact Cisco Systems.
9x Fatal--ISLT ASIC test. Switch is not operational. Contact Cisco Systems.
8x Fatal--Port control/status test. Switch is not operational. Contact Cisco Systems.
7x Fatal--System timer interrupt test. Switch is not operational. Contact Cisco Systems.
6x Fatal--CAM SRAM test. Switch is not operational. Contact Cisco Systems.
5x Nonfatal--Real-time clock test.

If this test failed, the switch will forward packets. However, should the switch unexpectedly shut down, the switch will be unable to restart itself automatically.

4x Nonfatal--Console port test.

If this test failed, you cannot access the management console through the console port. You can, however, Telnet to the management console.

3x Fatal--Content addressable memory test. Switch is not operational. Contact Cisco Systems.
2x Nonfatal--Built-in address test.

If this test failed, the switch uses the default Ethernet address of the switch and begins forwarding packets.

1x Nonfatal--Port loopback test.

If this test failed, it means some port functionality to one or more ports is lost. The switch disables any port(s) that failed this test, and the POST failure message on the Management Console Logon Screen indicates which port(s) did not pass this test. You should connect only to ports that have passed this test.

Diagnosing Problems

Table 4-2 lists symptoms, possible causes, and corrective actions associated with


Table 4-2: Common Problems and Their Solutions
Symptom Possible Cause Resolution

Poor performance or excessive errors

Incorrect full-duplex settings for 10BaseT and 100BaseT connections

Full-duplex status is shown with the Mode button and the FDUP LED.

Check the port statistics:

  • FCS and alignment errors on the port mean the switch port is configured for full-duplex operation and the other device is a repeater or half-duplex device.

  • Late collisions mean the port is configured for half-duplex operation and the attached device is full duplex.



Configure the port for half-duplex operation.



Configure the port for full-duplex operation.

Cabling distance exceeded

Port statistics show excessive FCS, late-collision, or alignment errors. For 100BaseTX connections:

  • The distance between the port and the attached device exceeds 100 meters.

  • If attached to a repeater, the total distance between the two end stations exceeds the 100BaseT cabling guidelines.

  • For 10BaseT connections: The distance between the port and the attached device exceeds 100 meters.


Reduce the cable length to within the recommended distances.

See your 100BaseT repeater documentation for cabling guidelines.

Reduce the cable length to within the recommended distances.

Bad adapter in attached device

Excessive errors found in port statistics.

Run the adapter card diagnostic utility.

No connectivity

Incorrect or bad cable

  • A crossover cable was used when straight-through was required, or vice-versa.

Bad cable

See the "Connectors and Cables" appendix for the correct pinouts and the proper use of crossover vs. straight-through cables.

Replace with a known good cable.

No management console access

Configuration problems Use the Diagnostic Console - Systems Engineering Menu to reset the switch.
Incorrect baud rate Reset the modem parameters to their factory defaults with the Diagnostic Console - System Debug Interface Menu.
Expansion Slot A or B LEDs off Incorrect Catalyst 2820 module installation See the Troubleshooting chapter in the Catalyst 2820 Modules User Guide.
RPS LED solid amber RPS not operational Verify that the RPS is connected properly to the switch, and is connected to a DC power outlet.
RPS LED flashing green

RPS and internal power supply both powered up Only one power source can be supplying power to the switch.

If you are using the RPS, the AC power cord of the switch must not be plugged in. If you are using the internal power supply, the RPS can be connected but must be powered down.
SYSTEM LED off Power cord not connected Plug in both ends of the power cord.
SYSTEM LED amber; port status LEDs off Corrupt firmware See the "Recovering from Corrupted Firmware" section of this chapter for firmware upgrade instructions.

Port status LED off

Devices not powered up Ensure both devices have power.
Cable connection loose Verify the connection at both ends of cable.
Wrong cable type Verify the cable type (crossover vs. straight-through).
Incorrect wiring See the "Connectors and Cables" appendix for pinout information.
Faulty cable Replace the cable with a known good one.
Port status LED alternating green and amber Link fault

Errors (such as excessive collisions, CRC errors, and alignment and jabber errors) could be affecting connectivity.
Verify port termination and check integrity of the connected devices.
Port status LED solid amber Port not forwarding

The port might be disabled by management, suspended due to an address violation, or suspended by Spanning-Tree Protocol due to the presence of network loops.

  • Investigate the device that is connected to the disabled port on the switch.

  • Enable the port through in-band or out-of-band management.

Using the Diagnostic Console

The diagnostic console is a menu-drive interface that you can use to perform the following tasks:

How you access the diagnostic console depends on which task you are performing.


Note Access to the Diagnostic Console - System Debug Interface Menu requires physical access to the switch. Remote users cannot display the password.

Diagnostic Console Logon Screen

To display the Diagnostic Console Logon Screen, follow these steps:

Step 1 Configure the physical characteristics of the management station or modem to match those of the console port (9600 baud, 8 data bits, 1 stop bit, no parity, no flow control), connect the console port to the management station or modem, and then start up your terminal emulation program.


Figure 4-2: Diagnostic Console Logon Screen
-------------------------------------------------
Cisco Systems Diagnostic Console
Copyright(c) Cisco Systems, Inc. 1997
All rights reserved.
Ethernet Address: 00-E0-1E-7E-B4-40
-------------------------------------------------
Press enter to continue.

Diagnostic Console - Systems Engineering Menu

To display the Diagnostic Console - Systems Engineering Menu (see Figure 4-3), press Return on the Diagnostic Console Logon Screen. Use the Diagnostic Console - Systems Engineering Menu to troubleshoot firmware problems and then bring up the firmware as usual.


Figure 4-3: Diagnostic Console - Systems Engineering Menu
Diagnostic Console  - Systems Engineering
Operation firmware version:  6.00 Status: valid
Boot firmware version:  3.02
[C] Continue with standard system start up
[U] Upgrade operation firmware (XMODEM)
[S] System Debug Interface
Enter Selection:

Operation firmware version--The current version of the switch firmware.

Status--Valid or invalid. If the firmware is not valid, the [C] option is not displayed, and the following warning is displayed:

WARNING!!! Operation Firmware is invalid
Upgrade firmware to enable switch operation.

Boot firmware version--Current version of the write-protected part of the firmware that supports the diagnostic console.

[C] Continue with standard system start up--Use this option after you have resolved the firmware problems with options [U] or [S]. The system exits the diagnostic console and brings up the firmware as usual.

[U] Upgrade operation firmware--Use this option to initiate a firmware upgrade. This option works with XMODEM and uses the default RS-232 parameters: 9600 baud,
8 data bits, 1 stop bit, no parity. You are prompted to choose a baud rate of 9600 or 57600 for the download. The console baud rate returns to 9600 immediately after the download.

Instead of using XMODEM, you can use 1KXMODEM to reduce download time significantly.

[S] System Debug Interface--Use this option to display the Diagnostic Console - System Debug Interface Menu shown in Figure 4-4.

Diagnostic Console - System Debug Interface Menu

To display the Diagnostic Console - System Debug Interface Menu (see Figure 4-4), select the [S] option from the Diagnostic Console - Systems Engineering Menu. Use this menu to reset the console port or the entire switch to the factory defaults. You can also use this menu to display the factory-installed management console password.


Note Access to the Diagnostic Console - System Debug Interface Menu requires physical access to the switch. Remote users cannot display the password.

Figure 4-4: Diagnostic Console - System Debug Interface Menu
Diagnostic Console  - System Debug Interface
[G] Generic I/O
[M] Memory (CPU) I/O
[F] Return system to factory defaults
[R] Reset main console RS232 interface to 9600,8,1,N
[V] View Management Console password
[P] POST diagnostic console
[X] Exit to Previous Menu
Enter Selection:

[G] Generic I/O--For Cisco personnel only.

[M] Memory (CPU) I/O--For Cisco personnel only.

[F] Return system to factory defaults--Use this option to return the switch to its factory settings. All static and dynamic addresses are removed, as are the IP address and all other configurations. Enter Y (yes) or N (no) and press Return. The changes take effect the next time the switch is reset.

[R] Reset main console RS232 interface to 9600, 8, 1, N--Use this option if you have lost the management console connection because of an improper modem configuration. The next time the switch is reset, the default RS-232 configuration is used.

[V] View Management Console password--Use this option to display the password set for the management console.

[P] POST diagnostic console--For Cisco personnel only.

Recovering from Corrupted Firmware

If the switch firmware has become corrupted, you can access the switch to upgrade the firmware. To recover from corrupted firmware, follow these steps:

Step 1 From the Diagnostic Console - Systems Engineering Menu (Figure 4-3), select the [U] option.

Step 2 Enter Y (yes) at the prompt to confirm the download:

It can take up to 1 minute to erase the existing firmware.


You are then prompted to choose a transmission speed. Enter 9 (for 9600) or
5 (for 57600) at the prompt:


The following prompt appears:


Step 3 Start the XMODEM transfer from the application you are running (make sure you have changed the baud rate on the application to match your selection).

The Diagnostic Console Logon Screen is displayed and the switch returns to 9600 baud when the upgrade is complete.


Press Return to display the Diagnostic Console - Systems Engineering Menu, and then select the [C] option to restart the switch using the upgraded firmware.


Recovering from a Lost or Forgotten Password

If you have forgotten the password set for the management console, you can view the password from the Diagnostic Console - System Debug Interface Menu (see Figure 4-4).

To display the password, select the [S] option on the Diagnostic Console - Systems Engineering Menu, and then select the [V] option on the Diagnostic Console - System Debug Interface Menu to display the management console password.

If you want to change the password, select the [M] option on the Console Settings Menu (see Figure 3-4).

Resetting the Switch to Factory Defaults

There can be times when you need the diagnostic console even though the firmware is valid. This could happen, for example, if the switch configuration prevents the firmware from executing properly and you cannot display the management console.

To reset to the switch to the factory defaults, select the [F] option from the Diagnostic Console - Systems Engineering Menu, and press Return. Then select the [C] option from the Diagnostic Console - Systems Engineering Menu to continue with system start up.

Resetting the Management Console to Factory Defaults

To reset to the management console to the factory defaults, follow these steps:

Step 1 Select the [S] option from the Diagnostic Console - Systems Engineering Menu, and press Return to display the Diagnostic Console - System Debug Interface Menu.

Step 2 Select the [R] option from the Diagnostic Console - System Debug Interface Menu, and press Return.

The following are the console port settings for normal operation: 9600 baud,
8 data bits, 1 stop bit, no parity, no flow control.


Step 3 Select the [C] option from the Diagnostic Console - Systems Engineering Menu to continue with system start up.

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