Installation guide

Chapter 3 Troubleshooting
Diagnosing Problems
3-4
Catalyst 3750 Switch Hardware Installation Guide
OL-6336-01
Table 3-1 Common Problems and Solutions
Symptom Possible Cause Resolution
Poor performance or excessive
errors
Duplex autonegotiation mismatch. See the switch software
configuration guide for
information on identifying
autonegotiation mismatches.
Verify that the autonegotiation
settings are the same at both
ends.
Cabling distance exceeded
•
Port statistics show excessive
frame check sequence (FCS),
late-collision, or alignment
errors.
• For 10/100 and
10/100/1000BASE-T
connections:
– The distance between the
port and the attached device
exceeds 328 feet (100
meters).
– If the switch is attached to a
repeater, the total distance
between the two end
stations exceeds the cabling
guidelines.
• XENPAK or SFP module
cabling guidelines exceeded.
• See the switch software
configuration guide for
information on displaying
port statistics.
• Reduce the cable length to
within the recommended
distances.
• See your repeater
documentation for cabling
guidelines.
• See your XENPAK or SFP
module documentation for
cabling guidelines.
Bad adapter in attached device
•
Excessive errors found in port
statistics.
• STP checking for possible
loops.
• Run adapter card diagnostic
utility.
• Wait 30 seconds for the port
LED to turn green.