Chapter 11

Troubleshooting

 


This chapter provides guidelines for users to identify and solve common problems. There are several ways to troubleshoot problems associated with the FS3-1600 installation and performance. The LEDs on the front panel are the quickest way to evaluate the operation of the switch. Detail traffic statistics provided by the management console. WebMan (Web-based Network Management) or SNMP management station can provide more details about the cause of connectivity and performance problems. The power-on self-test ensures that the switch is functioning properly at installation and when subsequently powered on.

If the switch does not operate properly or you are unable to access the management console, you can resolve these problems by using the management console described in “Switch Management Console Recovery Procedures.”

Frequent problems can be grouped into the following categories:


Power-on Self-test Failure

When the switch is first turned on and begins its Power-on Self-test, the power LED is turned on and diagnostic LED is off. After the Power-on Self-test completes successfully, the diagnostic LED stays on steadily, indicating that the switch is operational. If a test fails, the diagnostic LED stays off steadily.

When the Power-on Self-test completes successfully, Spanning-Tree Protocol (if enabled) immediately runs. Spanning-tree discovery takes approximately 30 seconds to complete, and no packet forwarding takes place during this time

Diagnosing Problems

Use Table 11-1 to identify your problem and resolve it.

Table 11-1: Symptoms and Resolutions

Symptom

Possible Cause

Resolution

All LEDs are off. Power failure or heat problems
  • The switch is not receiving AC power.
  • Fans are not operating, or blocked airflow is causing the unit to overheat.

 

Verify that the AC power is securely fastened at both ends and that power is available at the AC outlet.

Verify that sufficient space exists for adequate airflow at both sides of the switch.

Poor Performance or Excessive Errors Incorrect Full-Duplex Settings for Connections.
  • FCS and alignment errors on the port mean the switch port is configured for full duplex and the other device is a repeater of half-duplex device.
  • Late collisions mean the port is configured for half duplex and the attached device is full duplex

 

The FDX/COL LED on the front panel indicates a full-duplex setting. For more details, please check the Per Port Statistics in Switch Console Management.

Configure the port for half duplex.

Configure the port for full duplex.

Cabling Distance Exceeded.

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 100Base-TX cabling guidelines.

For 10BaseT connections:

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

 

Per Port Statistics show excessive FCS, late-collision, or alignment errors.

Reduce the cable length to within the recommended distances.

See your 100Base-TX repeater documentation for cabling guidelines.

Reduce the cable length to within the recommended distances.

Bad Adapter in Attached Device

 

Run adapter card diagnostic utility
No

Connectivity

 

Incorrect or Bad Cable.

The following are indicated by no link at both ends:

  • A crossover cable when straight-through was required, or vice-versa
  • Bad cable
See the “Connectors and Pin Assignment” in the Appendix A for the correct pinout and the proper use of crossover vs. straight-through cables.

Replace with tested good cable.

VLANs Misconfigured
  • Ports are assigned to different VLANs and cannot communicate.
Ensure the two nodes are connected to ports on the same VLAN. See the “VLAN Perspective” section in the “Working with the Console-Based Interface” chapter to list ports of a VLAN.
Diagnostic LED stay on or off Incorrect Software Code Attach a monitor to the serial port to display the diagnostic console. See the “Software Upgrade” section of chapter 5 for software upgrade instructions
No management console access
  • Configuration problems

 

  • Incorrect baud rate
Use the switch console management as described in the “Sofrware Upgrade” section of chapter 5 to reset the switch.

Reset the serial port parameters to their factory defaults with the switch console management.


Switch Management Console Recovery Procedures

The switch management console allows you to perform the following tasks:

If the switch software has become corrupted, you can access the switch to upgrade the software. For more details, follow the steps in the section “Upgrading Software” of Chapter 5.

If the current configuration prevents the switch from functioning properly, you can reload and reset the switch to the factory defaults. For more details, follow the steps in the section “Restore Default Settings” of Chapter 5.

For more details, follow the steps in the section “Changing the Console Baud Rate” of Chapter 5.

How you access the switch management console depends on which task you performing.

 

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