Chapter 10: Troubleshooting
Verify that the correct type of fiber optic cabling is being used.
Verify that the port is connected to the correct fiber optic cable. This is to eliminate the possibility that the port is connected to the wrong remote network device.
Try connecting another network device to the fiber optic port using a different cable. If the port is able to establish a link, then the problem is with the cable or other network device.
Use the switch’s management software to verify that the port is enabled.
If the remote network device is a managed device, use its management firmware to determine whether its port is enabled.
Test the attenuation of both directions on the fiber optic cable with a fiber optic tester to determine whether the optical signal is too weak (sensitivity) or too strong (maximum input power).
Problem 6: Network performance between a twisted pair port on the switch and a network device is slow.
Solution: There might be a duplex mode mismatch between the port and the network device. This can occur when a twisted pair port using auto- negotiation is connected to a remote device that has a fixed speed of 10 or 100 Mbps and a fixed duplex mode of full duplex. If this is the cause of the problem, adjust the duplex mode of the port on the network device or switch so that both ports are using the same duplex mode. You can use either the LEDs or management software on the switch to determine the duplex mode settings of the ports. The LEDs are described in Table 4 on page 31.
Problem 7: The switch functions intermittently.
Solutions: Check the system hardware status through the management software:
Use the SHOW SYSTEM ENVIRONMENT command in the Privileged Exec mode to verify that the input voltage from the power source to the switch is stable and within the approved operating range. The unit will shutdown if the input voltage fluctuates above or below the approved operating range.
Use the SHOW SYSTEM ENVIRONMENT command in the Privileged Exec mode to verify that the fan is operating correctly.
Verify that the location of the switch allows for adequate airflow. The unit will shutdown if it is in danger of overheating.
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