We recently added a redundant connection between two sites with ONS15454 chassis by adding two spans and an amplifier node in the middle. This was added to our existing five nodes. The original spans have stable span losses staying well within 1dB loss fluctuation. The new spans with the amplifier node are showing up to 8dB fluctuation in span loss. The new spans on either side of the amplifier node are 59 and 117km long. We have other spans of 112 and 123km which don't show any fluctuation. I noticed that the span loss looks to correlate to change in outside air temperature. Even if these spans are mostly aerial, should we expect this much change? We looked at a spec sheet from Corning fiber and according to their spec we should see less than 0.05dB/km across a 96degC temp range. We saw 8dB span loss change with a 33degC temp change on the 117km span.
I can't figure out why your system is responding the way it is. The need to add external attenuation on the MXPP definitely shows an issue.
As you mentioned earlier, you probably should contact the fiber's owner and see if they can troubleshoot or provide assistance. Maybe Cisco TAC can provide some insights.
I wish I had an answer.
if these spans are mostly aerial, should we expect this much change
Was reading ur message and saw mostly the cable is aerial. We shd not expect that much change.
Do you have any extra fiber where u can check power during the time it fluctuate in your 15454. Or can ask the vendore who is leasing you to check what is loss during that time.
Possible that aerial cable is experiencing something w.r.t temperature fluctuation .
As you said there are no alarms but if something is between the range of equipment why will it raise an alarm. Have you checked output power of all cards involved in between during that time.