Cisco 2940 - Manual (Page 52)

3-4
Catalyst 2940 Switch Hardware Installation Guide
OL-6157-01
Chapter 3 Troubleshooting
Diagnosing Common Problems
Table 3-2 Poor Performance Problems and Their Solutions
Symptom Possible Cause Resolution
Poor performance or excessive
errors. Duplex autonegotiation
mismatch. See the switch software
configuration guide for
information about identifying
autonegotiation mismatches.
Cabling distance exceeded.
• Port statistics show
excessive frame check
sequence (FCS),
late-collision, or alignment
errors. • See the switch software
configuration guide for
information about
displaying port statistics.
• For 10BASE-T,
100BASE-TX, and
1000BASE-T connections:
– The distance between
the port and the attached
device exceeds 328 feet
(100 meters). • Reduce cable length to
within the recommended
distances.
– If the switch is attached
to a repeater, the total
distance between the
two end stations
exceeds the cabling
guidelines. • See your repeater
documentation for cabling
guidelines.
• For SFP module
connections: The distance
between the SFP module
and the attached device
exceeds the SFP cabling
guidelines. • See Table 1-3 for cabling
guidelines.
Bad adapter in attached
device.
• Excessive errors found in
port statistics. • Run adapter card diagnostic
utility.
• Spanning Tree Protocol
(STP) is checking for
possible loops. • Wait 30 seconds for port
status LED to turn green.