3Com 4500G Series, Руководство по началу работы

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50 C
HAPTER
4: P
ROBLEM
S
OLVING
Solving Problems
Indicated by LEDs
If the LEDs on the switch indicate a problem, refer to the list of suggested
solutions below.
The PWR LED does not light
Check that the power cable is firmly connected to the switch and to the supply
outlet. If the connection is secure and there is still no power, you may have a faulty
power cord or an internal fault. Check the power cord by:
■
Testing it in another device.
■
Connecting a working power cord to the ‘problem’ device and contact your
supplier for advice.
On powering-up, the PWR LED lights Red
The switch unit has failed its Power On Self Test (POST) because of an internal
problem. The fault type will be indicated on the unit LEDs. Contact your supplier
for advice.
On powering-up, the PWR LED is flashing yellow
A port has failed and has been automatically disabled. You can verify this by
checking that the Port LED is quickly flashing Yellow. If a port fails, the switch
passes its Power On Self Test and continues to operate normally.
A Port LED is flashing yellow
The port has failed and has been automatically disabled. The switch passes its
Power On Self Test and continues to operate normally, even if one or more ports
are disabled.
A link is connected and yet the Port LED does not light
Check that:
■
The switch and the device at the other end of the link (or cable) are connected
securely.
■
The devices at both ends of the link are powered-up
■
The quality of cable is satisfactory
■
Auto-negotiation settings are the same at both ends.
Auto-negotiation problems will occur with 10BASE-T or 100BASE-T where
auto-negotiation is disabled and incorrect cables are being used (cross-over or
straight).
Auto-negotiation problems will occur with fiber if:
■
The Receiver (RX) and Transceiver (TX) cable connectors are swapped
■
Fibers are broken
■
Auto-negotiation differs at either end (a link appears at the ‘fixed’ end and
not at the auto-negotiation end)