Systems and methods include receiving first power snapshot from a receiving end of a foreign controlled link of the one or more foreign controlled optical links when there are no faults thereon; responsive to obtaining second power snapshot from the receiving end of the foreign controlled link, detecting a fault on one of at least one channel and part of the spectrum traversing the foreign controlled link; correlating the second power snapshot with the first power snapshots; and raising an indication of fault for the foreign controlled link based on the correlating.