The EXFO advisor is present on the OX1 interface. What makes a 5-star and what makes a 1-star value?
As opposed to the threshold system that gives a pass or a fail in an objective manner, the EXFO advisor system gives a qualitative insight on the quality of the fiber being measured.
The insertion loss and ORL are looked at and compared with the link length according to industry norms and graded accordingly. Some other aspects are also looked at, such as spacing between splices/connections, as well as the size of reflectance and losses due to those events, as well as the attenuation in between.
This qualitative assessment may or may not be appropriate for the evaluation of your fiber, so please keep your thresholds in mind when testing, over the EXFO advisor. A 1 star rating may still pass and a 5 star rating may still fail your thresholds.
More details about the EXFO advisor are available on the attached PDF.