3-3
Cisco ME 2400 Ethernet Access Switch Hardware Installation Guide
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Chapter 3 Troubleshooting
Diagnosing Problems
No connectivity Incorrect or bad cable
These are results of no link at both
ends:
• A crossover cable was used
when a straight-through was
required, or the reverse.
• The cable is wired incorrectly.
• A crossover or straight-through
cable is wired incorrectly.
• STP checking for possible
loops. STP is available only on
network node interfaces (NNIs).
• For the correct pinouts and
the proper application of
crossover instead of
straight-through cables, see
the “Two Twisted-Pair
Cable Pinouts” section on
page B-3.
• Enable the automatic
medium-dependent-
interface crossover
(auto-MDIX) feature.
• Replace with a tested good
cable.
• For 1000BASE-T
connections, be sure to use
a twisted four-pair,
Category 5 cable.
• Wait 30 seconds for the port
LED to turn green.
Unreadable characters on the
management console
Incorrect baud rate. Reset the emulation software to
9600 baud.
Amber system LED
Fatal POST error detected. Contact Cisco Systems.
The switch port is placed in
error-disabled state after SFP
module is inserted
Bad or non-Cisco-approved SFP
module.
Remove the SFP module from
the switch, and replace it with a
Cisco-approved module. Use the
errdisable recovery cause
gbic-invalid global
configuration command to
verify the port status, and enter a
time interval to recover from the
error-disabled state.
See the switch command
reference guide for information
on the errdisable recovery
command.
Table 3-1 Common Problems and Their Solutions (continued)
Symptom Possible Cause Resolution
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