Is paying for "protected circuits" actually worth it. Or are you better off just buying two circuits and using both during normal conditions. Use switching at layer 3 to the remaining circuit during abnormal conditions. Most of the time, you get twice the capacity for only twice the price instead of a "protected circuit" where you only get the once the capacity for twice the price.
Of course, there is still the problem some facility provider will "groom" both your circuits on to the same cable. If you are buying pre-emptable circuits, hopefully you understand what that means.
I've seen diverse protected circuits groomed, onto the same fiber bundle. One backhoe hit took out the first half of the cable, but the digger realized he goofed and stopped. The fiber company then cut the rest of the bundle to cleanly fix the cut... without warning anyone who was running on their failover protected circuit that something might be about to happen. Major collaboration vendor outage root-caused to that one... -george william herbert gherbert@retro.com