A former employer of mine tried to have redundant connections. They had two fibers from two different providers, going separate paths from their Dallas office,

A former employer of mine tried to have redundant connections. They had two fibers from two different providers, going separate paths from their Dallas office, etc. However, the 2nd provider utilized a 3rd provider as a regional carrier. And for about 100 miles between Dallas and Chicago, the fibers were run in conduits that were side by side. We discovered that when a single backhoe took down phones, data, etc, to all our southeast Region offices. (it also affected many others). Found out the hard way, that the 2nd providers redundant uplink also went through the same connection. Good luck tracing your fibers all the way from end to end.. Most of this stuff is all contracted to 3rd parties, and most don't want to give you detailed maps.