Cisco Catalyst 3560-X Software Configuration Manual page 1411

Chapter 1 Troubleshooting
Troubleshooting Power over Ethernet (PoE)
Figure 1-1 Power Over Ethernet Troubleshooting Scenarios
Symptom or problem
No PoE on only one port.
Trouble is on only one switch port. PoE and
non-PoE devices do not work on this port, but
do on other ports.
OL-25303-03
Possible cause and solution
Verify that the powered device works on another PoE port.
Use the show run, show interface status, or show power inline detail
user EXEC commands to verify that the port is not shut down or error
disabled.
Most switches turn off port power when the port is shut down,
Note
even though the IEEE specifications make this optional.
Verify that the Ethernet cable from the powered device to the switch port
is good: Connect a known good non-PoE Ethernet device to the Ethernet
cable, and make sure that the powered device establishes a link and
exchanges traffic with another host.
Verify that the total cable length from the switch front panel to the
powered device is not more than 100 meters.
Disconnect the Ethernet cable from the switch port. Use a short Ethernet
cable to connect a known good Ethernet device directly to this port on
the switch front panel (not on a patch panel). Verify that it can establish
an Ethernet link and exchange traffic with another host, or ping the port
VLAN SVI. Next, connect a powered device to this port, and verify that
it powers on.
If a powered device does not power on when connected with a patch cord to
the switch port, compare the total number of connected powered devices
to the switch power budget (available PoE). Use the show inline power
and show inline power detail commands to verify the amount of
available power.
For more information, see
Catalyst 3750-X and 3560-X Switch Software Configuration Guide
No PoE On One Port on Cisco.com.
Troubleshooting Tables
1-31