5-3
Catalyst 3650 Switch Hardware Installation Guide
OL-29734-01
Chapter 5 Troubleshooting
Diagnosing Problems
•
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
PoE and PoE+ Port Connections
A powered device connected to a PoE port does not receive power:
•
Verify the status of all ports. See and 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
shut down. Reenable the port if necessary.
•
Verify that the power supply installed in the switch meets the power requirements of your connected
devices. See the for more information.
•
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 compliant cabling to
connect Cisco prestandard IP phones, wireless access points, or IEEE 802.3af-compliant devices.
Note
The output of the PoE circuit has been evaluated as a limited power source (LPS) per IEC 60950.
SFP Modules
Use only Cisco SFP modules.
•
Inspect the uplink port and 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 and 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 shut down. Reenable the port if needed.
•
Make sure that all fiber connections are clean and securely connected.
•
For CX1 module connections and fiber connections, make sure that cable routing does not violate
the minimum allowed cable bend radius. See the module documentation for specific cabling
requirements.
Note
When ordering or using CX1 cables, ensure that the version identifier is 2 or higher.
•
For long wave SFP+ modules, a mode conditioning patch might improve performance over
maximum link distances with MMF connections.
