Allied Telesis AT-8518, Installation Manual

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3-1
Chapter 3
Troubleshooting
If you encounter problems when using the switch, this chapter may be helpful. If you
have a problem not listed here or in the AT-9108, AT-8518, AT-8525, and AT-8550
User’s Guide, contact your local technical support representative.
LEDs
Power LED does not light:
Check that the power cable is firmly connected to the device and to the supply outlet.
Check the unit fuse. For information on changing the fuse, see Appendix A.
On powering-up, the DIAG LED (AT-9108, AT-8218) or MGMT LED
(AT-8525, AT-8550) lights yellow:
The device has failed its Power On Self Test (POST) and you should contact your
supplier for advice.
A link is connected, but the Status LED does not light:
Check that:
"
All connections are secure.
"
Cables are free from damage.
"
The devices at both ends of the link are powered-up.
"
Both ends of the gigabit link are set to the same auto-negotiation state.
Both sides if the gigabit link must be enabled or disabled. If the two are differently
enabled, typically the side with auto-negotiation disabled will have the LINK LED
on, and the LINK LED on the side with auto-negotiation enabled will not light. The
default configuration for a gigabit port is auto-negotiation enabled. This can be
verified by entering the following command:
show port config