Chapter 4 Troubleshooting

Diagnosing Problems

Diagnosing Problems

Common switch problems fall into these categories:

Poor performance

No connectivity

Corrupted software

Table 4-1describes how to detect and resolve these problems.

 

 

 

 

Table 4-1

Common Problems and Solutions

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Symptom

 

 

Possible Cause

Resolution

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Poor performance or excessive

Duplex autonegotiation mismatch.

Refer to the switch software

 

 

 

 

 

errors

 

 

 

configuration guide for

 

 

 

 

 

 

 

 

 

information on identifying

 

 

 

 

 

 

 

 

 

autonegotiation mismatches.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Cabling distance exceeded

 

 

 

 

 

 

 

 

 

Port statistics show excessive

Refer to the switch software

 

 

 

 

 

 

 

 

frame check sequence (FCS),

configuration guide for

 

 

 

 

 

 

 

 

late-collision, or alignment

information on displaying

 

 

 

 

 

 

 

 

errors.

port statistics.

 

 

 

 

 

 

 

 

For SFP port connections:

Refer to your SFP

 

 

 

 

 

 

 

 

The distance between the

documentation for cabling

 

 

 

 

 

 

 

 

guidelines.

 

 

 

 

 

 

 

 

SFP port and the attached

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

device exceeds the SFP

 

 

 

 

 

 

 

 

 

cabling guidelines.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Bad adapter in attached device

 

 

 

 

 

 

 

 

 

Excessive errors found in port

Run adapter card diagnostic

 

 

 

 

 

 

 

 

statistics.

utility.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

No connectivity

 

 

Incorrect or bad cable

 

 

 

 

 

 

 

 

 

These are results of no link at both

 

 

 

 

 

 

 

 

 

ends:

 

 

 

 

 

 

 

 

 

A crossover cable was used

For the correct pinouts and

 

 

 

 

 

 

 

 

when a straight-through was

the proper application of

 

 

 

 

 

 

 

 

required, or the reverse.

crossover vs.

 

 

 

 

 

 

 

 

 

straight-through cables, see

 

 

 

 

 

 

 

 

 

the “Identifying a

 

 

 

 

 

 

 

 

 

Crossover Cable” section

 

 

 

 

 

 

 

 

 

on page B-2.

 

 

 

 

 

 

 

 

The cable is wired incorrectly.

Replace with a tested good

 

 

 

 

 

 

 

 

 

cable.

 

 

 

 

 

 

 

 

A crossover or straight-through

For 1000BASE-T

 

 

 

 

 

 

 

 

cable is wired incorrectly.

connections, be sure to use

 

 

 

 

 

 

 

 

 

a twisted four-pair,

 

 

 

 

 

 

 

 

 

Category 5 cable.

 

 

 

 

 

 

 

 

 

 

 

 

 

Cisco ME 4924-10GE Ethernet Switch Hardware Installation Guide

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

4-2

 

 

 

 

 

 

OL-10071-01

 

 

 

 

 

 

 

 

 

Page 54
Image 54
Cisco Systems ME 4924-10GE manual Diagnosing Problems, Symptom Possible Cause Resolution