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Catalyst 2960 and 2960-S Switch Software Configuration Guide
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Chapter 38 Troubleshooting
Monitoring SFP Module Status
If you are using a non-Cisco SFP module, remove the SFP module from the switch, and replace it with
a Cisco module. After inserting a Cisco SFP module, use the errdisable recovery cause gbic-invalid
global configuration command to verify the port status, and enter a time interval for recoverin g from the
error-disabled state. After the elapsed interval, the switch brings the interface out of the error-disabled
state and retries the operation. For more information about the errdisable recovery command, see the
command reference for this release.
If the module is identified as a Cisco SFP module, but the system is unable to read vendor-data
information to verify its accuracy, an SFP module error message is generated. In this case, you should
remove and re-insert the SFP module. If it continues to fail, the SFP module might be defective.
Monitoring SFP Module Status
You can check the physical or operational status of an SFP module by using the show interfaces
transceiver privileged EXEC command. This command shows the operational status, such as the
temperature and the current for an SFP module on a specific interface and the alarm status. You can also
use the command to check the speed and the duplex settings on an SFP module. For more information,
see the show interfaces transceiver command in the command reference for this release.
Using Ping
These sections contain this information:
• Understanding Ping, page 38-14
• Executing Ping, page 38-15

Understanding Ping

The switch supports IP ping, which you can use to test connectivity to remote hosts. Ping sends an echo
request packet to an address and waits for a reply. Ping returns one of these responses:
• Normal response—The normal response (hostname is alive) occurs in 1 to 10 seconds, depending
on network traffic.
• Destination does not respond—If the host does not respond, a no-answe r message is returned.
• Unknown host—If the host does not exist, an unknown host message is returned.
• Destination unreachable—If the default gateway cannot reach the specified network, a
destination-unreachable message is returned.
• Network or host unreachable—If there is no entry in the route table for the host or network, a
network or host unreachable message is returned.