CHAPTER
3-1
Catalyst2940 Switch Hardware Installation Guide
OL-6157-01
3
Troubleshooting
The front-panel LEDs provide troubleshooting information about the switch. They show power-on
self-test (POST) failures, port-connectivity problems, and overall switch performance. For a full
description of the LEDs, see the “LEDs” section on page 1-6.
You can also get statistics from the device manager, the Network Assistant application, the
command-line interface (CLI), or a Simple Network Management Protoc ol (SNMP) workstation. See the
switch software configuration guide, the switch command reference , or the documentation that came
with your SNMP application for details.
This chapter provides these topics for troubleshooting proble ms:
•Understanding POST Results, page 3-1
•Diagnosing Common Problems, page 3-1

Understanding POST Results

While the switch powers on, it automatically begins POST, a series of tests that verifies that the switch
functions properly. POST lasts approximately 1 minute.
If POST passes successfully, only the SYST and STAT LEDs, as shown in Figure1 -3 on page 1-6,
remain on.
If POST fails, the SYST LED turns amber. Table3-3 on page 3-5 lists two causes and resolutions for a
POST failure. POST failures are usually fatal. Contact your Cisco representative if your switch does not
pass POST.

Diagnosing Common Problems

Common switch problems fall into these categories:
•Connectivity problems (Table 3- 1)
•Poor performance (Tabl e 3-2)
•Corrupted software (Table 3- 3)