Cisco Systems OL-6157-01 manual Symptom Possible Cause Resolution, B-5 through

Chapter 3 Troubleshooting

Diagnosing Common Problems

Table 3-1 Common Connectivity Problems and Their Solutions

Symptom	Possible Cause	Resolution
No connectivity to 10/100 ports	Incorrect or bad cable.
or 10/100/1000 port.
	These are the results of no link at
	both ends:
	• Cable not properly installed	• Remove and reconnect cable
		to switch and PC. Wait 30
	between switch and PC.
		seconds for port status LED
		on switch to turn green.
	• A crossover cable was used	• To identify a crossover
	when a straight-through was	cable, see Figure B-12 on
	required, or vice-versa.	page B-9.
	• The cable is wired	• Verify that the cable is wired
	incorrectly.	correctly. See Figure B-6 on
		page B-5through
		Figure B-9 on page B-6for
		the correct pinouts of 10/100
		cables. For the proper
		application of crossover and
		straight-through cables, see
		the “Cable and Adapter
		Specifications” section on
		page B-5.
		• Replace it with a tested good
		cable.
	• STP is checking for possible	• Wait 30 seconds for port
	network loops.	status LED to turn green.
No connectivity to	An SFP module was installed in	Remove the SFP module, and
100BASE-FX port.	the switch at power on.	reboot the switch.
	Note The SFP module slots	Note See the “Connecting to
	and the 100BASE-FX	an SFP Module” section
	port cannot both be used	on page 2-12and the
	at the same time. If an	Cisco Small
	SFP module is installed	Form-Factor Pluggable
	when the switch is	Modules Installation
	powered on, the	Notes (order number
	100BASE-FX port is	DOC-7815160=) for
	disabled.	procedures on removing
		an SFP module.

Catalyst 2940 Switch Hardware Installation Guide

3-2 OL-6157-01