Cisco Catalyst 2960 Software Configuration Manual page 919

Chapter 39 Troubleshooting
Table 39-6 Power Over Ethernet Troubleshooting Scenarios (continued)
Symptom or problem
No PoE on all ports or a group of ports.
Trouble is on all switch ports.
Nonpowered Ethernet devices cannot
establish an Ethernet link on any port, and
PoE devices do not power on.
OL-26520-01
Possible cause and solution
If there is a continuous, intermittent, or reoccurring alarm related to power,
replace the power supply if possible it is a field-replacable unit. Otherwise,
replace the switch.
If the problem is on a consecutive group of ports but not all ports, the power
supply is probably not defective, and the problem could be related to PoE
regulators in the switch.
Use the show log privileged EXEC command to review alarms or system
messages that previously reported PoE conditions or status changes.
If there are no alarms, use the show interface status command to verify that the
ports are not shut down or error-disabled. If ports are error-disabled, use the shut
and no shut interface configuration commands to re-enable the ports.
Use the show env power and show power inline privileged EXEC commands to
review the PoE status and power budget (available PoE).
Review the running configuration to verify that power inline never is not
configured on the ports.
Connect a nonpowered Ethernet device directly to a switch port. Use only a short
patch cord. Do not use the existing distribution cables. Enter the shut and no shut
interface configuration commands, and verify that an Ethernet link is established.
If this connection is good, use a short patch cord to connect a powered device to
this port and verify that it powers on. If the device powers on, verify that all
intermediate patch panels are correctly connected.
Disconnect all but one of the Ethernet cables from switch ports. Using a short
patch cord, connect a powered device to only one PoE port. Verify the powered
device does not require more power than can be delivered by the switch port.
Use the show power inline privileged EXEC command to verify that the powered
device can receive power when the port is not shut down. Alternatively, watch the
powered device to verify that it powers on.
If a powered device can power on when only one powered device is connected to
the switch, enter the shut and no shut interface configuration commands on the
remaining ports, and then reconnect the Ethernet cables one at a time to the
switch PoE ports. Use the show interface status and show power inline
privileged EXEC commands to monitor inline power statistics and port status.
If there is still no PoE at any port, a fuse might be open in the PoE section of the
power supply. This normally produces an alarm. Check the log again for alarms
reported earlier by system messages.
Catalyst 2960 and 2960-S Switches Software Configuration Guide, Release 15.0(1)SE
Troubleshooting Tables
39-31