Rural phone calls lost in web of 'least-cost-routing' services. (Milwaukee Journal Sentinel, 8/23/2014)
Sounds more like rural call incompletion to me. The problem happens largely in rural areas because that's where long-distance or wireless carriers pay higher-than-average fees to the local phone company to complete calls, according to the FCC. Those fees help pay for the rural networks. But to reduce their own costs, some long-distance or wireless companies today will contract with third-party "least-cost-routing" services to connect those types of calls at the lowest price possible.
TransNexus, a software development company specializing in applications for managing wholesale VoIP networks, sez least cost routing is a simple practice that finds the most inexpensive way to route phone calls.
Simple and, apparently, 80% effective.
So effective that West Virginia's Twin Valley Telephone provides this diagram and explanation for its customers on its homepage. (So you know it's happening frequently.)
In layman’s terms, the carrier of the person who makes the call is trying to the find the absolute least cost to get the call from point A, the caller, to point B, you. Think of it like a car driving across the nation taking only back country roads to avoid paying tollways to use interstate. The end result is less than satisfactory. The call might be very poor quality by the time it has taken all those “back roads,” or worse, not get to you at all.