Allied Telesis AT-DC2552XS, Installation Manual, Page: 88 / 96

Chapter 8: Troubleshooting
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
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 either the cable or the other network device.

Use the switch’s management software to verify that the port is
enabled. Refer to
AT-DC2552XS / L3 Management Software
Command Line Interface User’s Guide for information concerning
specific commands.

If the remote network device is a managed device, use its
management firmware to determine whether its port is enabled.

Test the attenuation on the fiber optic cable with a fiber optic tester
to determine whether the input optical signal is too weak
(sensitivity) or too strong (maximum input power).
Problem: The LINK/ACT LED for a QSFP+ transceiver is off.
Solutions: The fiber optic port on the module is unable to establish a link
to a network device. Try the following:

Verify that the network device connected to the fiber optic port is
operating properly.

Verify that the fiber optic cable is securely connected to the port on
the QSFP+ transceiver and to the port on the remote network
device.

Check that the QSFP module is fully inserted in the slot.

Verify that the operating specifications of the fiber optic ports on
the QSFP+ transceiver and the remote network device are
compatible.

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 either the cable or the other network device.

Use the switch’s management software to verify that the port is
enabled. Refer to
AT-DC2552XS / L3 Management Software
Command Line Interface User’s Guide for information concerning
specific commands.

If the remote network device is a managed device, use its
management firmware to determine whether its port is enabled.