Because dispersion is not usually measured in the field, it is
important to determine if attenuation is the most likely cause of
a link failure. Therefore, analyze the failing link environment before
proceeding with fault isolation.
The following questions can help isolate the error when performing
link failure analysis.
- What is the status of similar links and devices?
- Are there any substitute devices?
- Are there any spare optical fiber pairs?
- Is this the first time that the failing link or links have been
used?
- Has this cabling combination been used before?
- If it is an FDDI link, has an optical bypass switch been installed
in the link?
- Has this cabling combination been used for another application
that had a different wavelength?
- Is the cabling plant a new installation?
- Was the cabling plant installed to support an ATM, FICON®, or FDDI environment?
- Was the cabling plant installed over a period of time?
- Was the cabling plant previously used to support other applications?
- Is there a mixture of fiber types within the cabling plant?
- Is there a mixture of fiber types within the same distribution
panel?
- Is there a mixture of applications using the same distribution
panel?
- Is this the first time that part of the cabling plant was configured
in the link?
- Are the cabling plant lengths and specifications available?