Cisco Systems OL-6157-01 manual Poor performance or excessive

Chapter 3 Troubleshooting

Diagnosing Common Problems

Table 3-2 Poor Performance Problems and Their Solutions

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

Catalyst 2940 Switch Hardware Installation Guide

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