Troubleshooting guide

3. Troubleshooting Functional Failures During Operation
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1. Checking the log
For details about the log, see the manual Message and Log Reference.
2. Isolating the cause of the problem according to the failure analysis method
Isolate the cause of the problem according to the failure analysis method described in the
following table.
Table 3-11: Failure analysis method for 100BASE-FX/1000BASE-X problems
No. Items to check Cause Action
1Use the
show
interfaces command to
display the failure
statistics, and check
whether there is a count for
the following item for the
target port. If there is a
count, see the Cause and
Action columns.
• Link down
• Signal detect errors
Line quality on
the receiving side
is degraded.
Check the type of the optical fiber. For the types, see the
Hardware Instruction Manual.
If an optical attenuator is used, check the attenuation value. For
the optical level, see the Hardware Instruction Manual.
Check the cable length. For the cable length, see the Hardware
Instruction Manual.
Check whether the cables are connected correctly (for
example, check for incomplete insertion). Make sure that the
end sections of the cables are clean. If they are dirty, clean
them.
Check whether the transceiver is connected correctly.
For the
speed and duplex configuration commands, specify
the same values that are on the remote device.
Comply with the segment standard of the remote device.
Check whether the optical level is correct. For the optical level,
see the Hardware Instruction Manual.
Perform a line test on the Switch and make sure that the
functionality of the receiving side has no problem. Check the
results of the
no test interfaces command, and take the
action described in Action. For the test types to be specified,
see 6.1 Testing a line.
2Use the
show
interfaces command to
display the failure
statistics for the receiving
side, and check whether
there are counts for the
following items for the
target port. If there is a
count, see the Cause and
Action columns.
• CRC errors
• Symbol errors
Line quality on
the receiving side
is degraded.
Check the type of the optical fiber. For the mode, see the
Hardware Instruction Manual.
If an optical attenuator is used, check the attenuation value. For
the optical level, see the Hardware Instruction Manual.