AT&T Fiber Cut Impacts Silicon Valley > services are out

said by elbm:

Diversity usually follows these kind outages. As another poster said most rings are collapsed rings e.g. all 4 fibers under one sheath. Gives the carriers some redundancy but no diversity.

Diverse entrance/route/pop/co builds are very expensive and end users (not individual users-- wireless providers, isps, big business...) often don't realize how vulnerable they are until a failure happens. I have spent the last several years on diversity projects for wireless carriers, large brokerage firms, back haul providers-- all of which are reacting to major outages because of fiber failures.