Troubleshooting

Diagnosing with the LEDs

Tip

Problem

Solution

 

 

 

➏The network connection is not working properly.

Try the following procedures:

•For the indicated port, verify that both ends of the cabling, at the switch and the connected device, are connected properly.

•Verify the connected device and switch are both powered on and operating correctly.

•Verify you have used the correct cable type for the connection:

–For twisted-pair connections to the fixed 10/100 or 10/100/1000 ports, if the port is configured to “Auto” (auto negotiate), either straight-through or crossover cables can be used because of the switch’s “Auto-MDIX” feature and the Auto MDI/MDI- X feature of the 10/100/1000-T port.

Troubleshooting

Note: If the switch port configuration is changed to one of the fixed configuration options (for example, 100 Mbps/Full Duplex), then the port operates as MDI-X only and you must use the correct type of cable for the connection. In general, for connecting an end node (MDI port) to the switch, use straight-through cable; for connecting to MDI-X ports on hubs, other switches, and routers, use crossover cable.

–For fiber-optic connections, verify the transmit port on the switch is connected to the receive port on the connected device, and the switch receive port is connected to the transmit port on the connected device.

•For the dual-personality 10/100/1000-T ports, be sure a mini-GBIC is not installed in the associated slot.

•For 1000Base-T connections, verify the network cabling complies with the IEEE 802.3ab standard. The cable should be installed according to the ANSI/TIA/EIA-568-A-5 specifications. Cable testing should comply with the stated limitations for Attenuation, Near-End Crosstalk, Far-End Crosstalk, Equal-Level Far-End Crosstalk (ELFEXT), Multiple Disturber ELFEXT, and Return Loss.

The cable verification process must include all patch cables from any end devices, including the switch, to any patch panels in the cabling path.

•Verify the port has not been disabled through a switch configuration change. You can use the console interface, or, if you have configured an IP address on the switch, use the web browser interface to determine the state of the port and re-enable the port if necessary.

•Verify the switch port configuration matches the configuration of the attached device. For example, if the switch port is configured as “Auto”, the port on the attached device also MUST be configured as “Auto”. Depending on the port type, twisted-pair or fiber- optic, if the configurations don’t match, the results could be a very unreliable connection, or no link at all.

•If the other procedures don’t resolve the problem, try using a different port or a different cable.

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