Cisco Systems IE20004TSB 10/100 and 10/100/1000 Port Connections, SFP Module, Interface Settings

Chapter 3 Troubleshooting

Diagnosing Problems

10/100 and 10/100/1000 Port Connections

If a port appears to malfunction:

•Verify the status of all ports. See Table 1-9 on page 1-17for descriptions of the LEDs and their meanings.

•Use the show interfaces privileged EXEC command to see if the port is error-disabled, disabled, or shut down. Reenable the port if necessary.

•Verify the cable type. See Appendix B, “Cable and Connectors”.

SFP Module

Use only Cisco SFP modules. Each Cisco module has an internal serial EEPROM that is encoded with security information. This encoding verifies that the module meets the requirements for the switch.

•Inspect the SFP module. Exchange the suspect module with a known good module.

•Verify that the module is supported on this platform. (The switch release notes on Cisco.com list the SFP modules that the switch supports.)

•Use the show interfaces privileged EXEC command to see if the port or module is error-disabled, disabled, or shutdown. Reenable the port if needed.

•Make sure that all fiber-optic connections are clean and securely connected.

Interface Settings

Verify that the interface is not disabled or powered off. If an interface is manually shut down on either side of the link, it does not come up until you reenable the interface. Use the show interfaces privileged EXEC command to see if the interface is error-disabled, disabled, or shut down on either side of the connection. If needed, reenable the interface.

Ping End Device

Ping from the directly connected switch first, and then work your way back port by port, interface by interface, trunk by trunk, until you find the source of the connectivity issue. Make sure that each switch can identify the end device MAC address in its Content-Addressable Memory (CAM) table.

Spanning Tree Loops

STP loops can cause serious performance issues that look like port or interface problems.

A unidirectional link can cause loops. It occurs when the traffic sent by the switch is received by the neighbor, but the traffic from the neighbor is not received by the switch. A broken cable, other cabling problems, or a port issue can cause this one-way communication.

You can enable UniDirectional Link Detection (UDLD) on the switch to help identify unidirectional link problems. For information about enabling UDLD on the switch, see the “Understanding UDLD” section in the switch software configuration guide on Cisco.com.

Cisco IE 2000 Switch Hardware Installation Guide

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