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Catalyst 2960-S Switch Hardware Installation Guide
OL-19732-04
Chapter 3 Troubleshooting
Diagnosing Problems
10/100 or 10/100/1000 Port Connections
A port appears to malfunction:
• Use the Mode button to show the status for all ports. See Table 1-8 and Ta ble 1-9 for descriptions of
the LEDs and their meanings.
• Use the show interfaces privileged EXEC command to see if the port is error-disabled, disabled, or
shutdown. Re-enable the port if necessary.
10/100 or 10/100/1000 PoE Port Connections
A powered device connected to PoE port does not receive power:
• Use the Mode button to show the PoE status for all ports. See Table 1-8 and Table 1-9 for
descriptions of the LEDs and their meanings.
• Use the show interfaces privileged EXEC command to see if the port is in error-disabled, disabled,
or shutdown. Re-enable the port if necessary.
• Verify that the power supply installed in the switch meets the power requirements of your connected
devices. See the “10/100 PoE+ Ports” section on page 1-5 and the “10/100/1000 PoE+ Ports” section
on page 1-5.
• Verify the cable type. Many legacy powered devices, including older Cisco IP phones and access
points that do not fully support IEEE 802.3af, might not support PoE when connected to the switch
by a crossover cable. Replace the crossover cable with a straight-through cable.
Caution Noncompliant cabling or powered devices can cause a PoE port fault. Use only standard-compliant
cabling to connect Cisco prestandard IP Phones and wireless access points or IEEE 802.3af-compliant
devices. You must remove any cable or device that causes a PoE fault.
SFP and SFP+ Module
Use only Cisco SFP or SFP+ modules in the switch. Each Cisco module has an internal serial EEPROM
that is encoded with security information. This encoding provides a way for Cisco to identify and
validate 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. Re-enable the port if needed.
• Make sure that all fiber-optic connections are properly cleaned 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 re-enable the interface. Use the show interfaces privileged
EXEC command to see if the interface is error-disabled, disabled, or shutdown on either side of the
connection. If needed, re-enable the interface.