McDATA Sphereon 4500 User Manual page 90

Monitoring and Managing the Switch
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McDATA® Sphereon™ 4500 Fabric Switch Product Manager User Manual
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• Discarded frames
A received frame could not be routed and was discarded because
the frame timed out (insufficient buffer-to-buffer credit) or the
destination device was not logged into the switch.
• Invalid transmission words
The number of times that the switch detected invalid
transmission words from the attached device. This indicates that
a frame or primitive sequence arrived at the switch's port
corrupted. This corruption can be due to the attached device
performing a reset, plugging or unplugging the link, bad optics at
either end of the cable, bad cable, or a dirty or poor connection.
Moving the connection around or replacing cables can isolate the
problem.
Some number of invalid transmission words are expected and
acceptable. Invalid transmission words within a frame are used to
produce the bit-error threshold link incident. If one or more
invalid transmission words are detected in 12 separate 1.5-second
samples within five minutes, a bit-error threshold link incident is
generated.
• CRC errors
A received frame failed a cyclic redundancy check (CRC)
validation, indicating the frame arrived at the switch's port
corrupted. Frame corruption may be caused by device
disconnection, an optical transceiver failure at the device, a bad
fiber-optic cable, or a poor cable connection.
• Delimiter errors
The number of times that the switch detected an unrecognized
start-of-frame (SOF), an unrecognized end-of-frame (EOF)
delimiter, or an invalid class of service. This indicates that the
frame arrived at the switch's port corrupted. This corruption can
be due to plugging/unplugging the link, bad optics at either end
of the cable, bad cable, or dirty or poor connections. Moving the
connection around or replacing cables can isolate the problem.
• Address ID errors
A received frame had an unavailable or invalid Fibre Channel
destination address, or an invalid Fibre Channel source address.
This typically indicates the destination device is unavailable.