Sfp Module; Interface Settings; Ping End Device; Spanning Tree Loops - Cisco IE-4000-4TC4G-E Hardware Installation Manual

Chapter 4 Troubleshooting
10/100/1000 Port Connections
If a port appears to malfunction:
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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.
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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.
Verify the status of all ports by checking the LEDs. For more information, see
page 4-2..
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
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.
Appendix C, "Cable and Connectors".
Cisco IE 4000 Switch Hardware Installation Guide
Diagnosing Problems
Switch LEDs,
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